Search

Background: Phelan-McDermid syndrome (PMS) is caused by monoallelic loss or inactivation at the SHANK3 gene, located in human chr 22q13.33, and is often associated with Autism Spectrum Disorder (ASD). Objectives: To assess the clinical and developmental phenotype in a novel sample of PMS patients, including for the first time auxometric trajectories and serotonin blood levels. Methods: 70 Italian PMS patients were clinically characterized by parental report, direct medical observation, and a thorough medical and psychodiagnostic protocol. Serotonin levels were measured in platelet-rich plasma by HPLC. Results: Our sample includes 59 (84.3%) cases with chr. 22q13 terminal deletion, 5 (7.1%) disruptive SHANK3 mutations, and 6 (8.6%) ring chromosome 22. Intellectual disability was present in 69 (98.6%) cases, motor coordination disorder in 65 (92.9%), ASD in 20 (28.6%), and lifetime bipolar disorder in 12 (17.1%). Prenatal and postnatal complications were frequent (22.9%-48.6%). Expressive and receptive language were absent in 49 (70.0%) and 19 (27.1%) cases, respectively. Decreased pain sensitivity was reported in 56 (80.0%), hyperactivity in 49 (80.3%), abnormal sleep in 45 (64.3%), congenital dysmorphisms in 35 (58.3%), chronic stool abnormalities and especially constipation in 29 (41.4%). Parents reported noticing behavioral abnormalities during early childhood immediately after an infective episode in 34 (48.6%) patients. Brain MRI anomalies were observed in 53 (79.1%), EEG abnormalities in 16 (23.5%), kidney and upper urinary tract malformations in 18 (28.1%). Two novel phenotypes emerged: (a) a subgroup of 12/44 (27.3%) PMS patients displays smaller head size at enrollment (mean age 11.8 yrs) compared to their first year of neonatal life, documenting a deceleration of head growth (p < 0.001); (b) serotonin blood levels are significantly lower in 21 PMS patients compared to their 21 unaffected siblings (P < 0.05), and to 432 idiopathic ASD cases (p < 0.001). Conclusions: We replicate and extend the description of many phenotypic characteristics present in PMS, and report two novel features: (1) growth trajectories are variable and head growth appears to slow down during childhood in some PMS patients; (2) serotonin blood levels are decreased in PMS, and not increased as frequently occurs in ASD. Further investigations of these novel features are under way. [ABSTRACT FROM AUTHOR]

Zinc and RING finger 3 (ZNRF3) is a negative-feedback regulator of Wnt/β-catenin signaling, which plays an important role in human brain development. Although somatically frequently mutated in cancer, germline variants in ZNRF3 have not been established as causative for neurodevelopmental disorders (NDDs). We identified 12 individuals with ZNRF3 variants and various phenotypes via GeneMatcher/Decipher and evaluated genotype-phenotype correlation. We performed structural modeling and representative deleterious and control variants were assessed using in vitro transcriptional reporter assays with and without Wnt-ligand Wnt3a and/or Wnt-potentiator R-spondin (RSPO). Eight individuals harbored de novo missense variants and presented with NDD. We found missense variants associated with macrocephalic NDD to cluster in the RING ligase domain. Structural modeling predicted disruption of the ubiquitin ligase function likely compromising Wnt receptor turnover. Accordingly, the functional assays showed enhanced Wnt/β-catenin signaling for these variants in a dominant negative manner. Contrarily, an individual with microcephalic NDD harbored a missense variant in the RSPO-binding domain predicted to disrupt binding affinity to RSPO and showed attenuated Wnt/β-catenin signaling in the same assays. Additionally, four individuals harbored de novo truncating or de novo or inherited large in-frame deletion variants with non-NDD phenotypes, including heart, adrenal, or nephrotic problems. In contrast to NDD-associated missense variants, the effects on Wnt/β-catenin signaling were comparable between the truncating variant and the empty vector and between benign variants and the wild type. In summary, we provide evidence for mirror brain size phenotypes caused by distinct pathomechanisms in Wnt/β-catenin signaling through protein domain-specific deleterious ZNRF3 germline missense variants. [Display omitted] Boonsawat et al. establish germline missense variants in the tumor suppressor gene ZNRF3 as a cause of neurodevelopmental disorders (NDDs) with microcephaly or macrocephaly, depending on the functional/domain-specific effects of the variants on Wnt/β-catenin signaling. This study finds that ZNRF3 haploinsufficiency does not cause NDDs but rather other phenotypes. [ABSTRACT FROM AUTHOR]

Background/Objectives: Identifying novel variants in very rare disease genes can be challenging when patients exhibit a complex phenotype that expands the one described, and we provide such an example here. A few terminal truncating variants in KIDINS220 cause spastic paraplegia (SP), intellectual disability (ID), nystagmus, and obesity (SINO, MIM #617296). Prompted by the result of next-generation sequencing on a patient referred for SP associated with complex brain dysmorphisms, we reviewed the phenotype of SINO patients focusing on their brain malformations, mainly described in prenatal age and first years of life, and tried to understand if the predicted effect of the mutant kidins220 may have caused them. Methods: We performed whole exome sequencing (WES) and a literature and mutation databases review. Results: We report a young adult with SP, severe ID, strabismus, and macrocephaly exhibiting brain malformations at follow-up, partially overlapping with those described in TUBB3 tubulinopathy. WES analysis of the proband and parents identified the heterozygous de novo variant (NM_020738.4: c. 4144G > T) p. Glu 1382* in KIDINS220 that was predicted to be causative of SINO. Conclusions: The progression of myelination and the development of brain structures turned out to be crucial for identifying, at follow-up, the whole KIDINS220-related brain malformations. The truncated proteins associated with SINO lack a portion fundamental for the interaction of kidins220 with tubulins and microtubule-associated proteins. The complexity of the brain malformations displayed by our patient, and possibly by other reported SINO patients, could result from an impaired dynamic modulation of the microtubule cytoskeleton during embryogenesis. Brain malformations must be considered as part of the SINO spectrum phenotype. [ABSTRACT FROM AUTHOR]

The etiology of neurodevelopmental disorders and epilepsy is very heterogeneous and partly still unknown, and the research of causative genes related to these diseases is still in progress. In 2020, pathogenic variants of the TET3 gene were associated with Beck–Fahrner syndrome, which is characterized by neurodevelopmental delay, intellectual and learning disabilities of variable degree, growth abnormalities, hypotonia and seizures. Variants of TET3 have been described having both an autosomal dominant with a milder phenotype and an autosomal recessive pattern. To date, in the literature, only 28 patients are reported with pathogenic variants of the TET3 gene, and only 9 of them have epilepsy. We describe a 31-year-old woman with macrocephaly, mild neurodevelopmental delay and a long history of epilepsy. Trio-based exome sequencing identified a de novo heterozygous TET3 variant, c.2867G>A p.(Arg956Gln), never described before, absent in the general population and predicted to be potentially pathogenetic by bioinformatics tools. This report aims to describe the clinical history of our patient, the pharmacological treatment and clinical response, as well as the biological characteristics of this new variant. [ABSTRACT FROM AUTHOR]

Imagawa-Matsumoto syndrome (IMMAS; MIM #618786) is an autosomal dominant syndrome characterized by overgrowth, dysmorphic features, musculoskeletal abnormalities, developmental delay, and intellectual disability. The first case was reported in 2017 and has subsequently been diagnosed in only another 12 patients. We also present the first IMMAS patient from Turkey. A 19-year-old female was admitted to the neurology outpatient clinic due to a behavioral disorder and intellectual disability. Her physical examination revealed macrocephaly and dysmorphic features like a round face, broad forehead, hypertelorism, and variable skeletal anomalies such as flat feet, clinodactyly, and macrocephaly. Cranial magnetic resonance imaging (MRI) showed agenesis of the corpus callosum and polymicrogyria. Chromosomal analysis results were consistent with a normal constitutional female karyotype and microarray analysis showed a de novo 1.5-MB size deletion on the long arm of chromosome 17; band q11.2 encompassing the Polycomb Repressive Complex 2 Subunit (SUZ12 gene, MIM *606245). This report will contribute to the limited information in the literature. [ABSTRACT FROM AUTHOR]

Abstract Background Phelan-McDermid syndrome (PMS) is caused by monoallelic loss or inactivation at the SHANK3 gene, located in human chr 22q13.33, and is often associated with Autism Spectrum Disorder (ASD). Objectives To assess the clinical and developmental phenotype in a novel sample of PMS patients, including for the first time auxometric trajectories and serotonin blood levels. Methods 70 Italian PMS patients were clinically characterized by parental report, direct medical observation, and a thorough medical and psychodiagnostic protocol. Serotonin levels were measured in platelet-rich plasma by HPLC. Results Our sample includes 59 (84.3%) cases with chr. 22q13 terminal deletion, 5 (7.1%) disruptive SHANK3 mutations, and 6 (8.6%) ring chromosome 22. Intellectual disability was present in 69 (98.6%) cases, motor coordination disorder in 65 (92.9%), ASD in 20 (28.6%), and lifetime bipolar disorder in 12 (17.1%). Prenatal and postnatal complications were frequent (22.9%-48.6%). Expressive and receptive language were absent in 49 (70.0%) and 19 (27.1%) cases, respectively. Decreased pain sensitivity was reported in 56 (80.0%), hyperactivity in 49 (80.3%), abnormal sleep in 45 (64.3%), congenital dysmorphisms in 35 (58.3%), chronic stool abnormalities and especially constipation in 29 (41.4%). Parents reported noticing behavioral abnormalities during early childhood immediately after an infective episode in 34 (48.6%) patients. Brain MRI anomalies were observed in 53 (79.1%), EEG abnormalities in 16 (23.5%), kidney and upper urinary tract malformations in 18 (28.1%). Two novel phenotypes emerged: (a) a subgroup of 12/44 (27.3%) PMS patients displays smaller head size at enrollment (mean age 11.8 yrs) compared to their first year of neonatal life, documenting a deceleration of head growth (p

Fetal intracranial teratoma presents a rare and devastating diagnosis. Typically, this condition is first detected during routine prenatal ultrasounds, appearing as an irregular heterogeneous lesion. Further insights are gained through fetal magnetic resonance imaging (MRI), better characterizing the anomaly. The combination of these modalities provides detail-oriented high resolution MRI images, while follow-up ultrasounds capture dynamic growth changes, serving as a cost-effective and easily accessible adjunct. This fast-growing tumor leads to macrocephaly and ventriculomegaly, causing severe distortion of the brain parenchyma. Early detection is crucial for effective fetal management and preventing maternal complications. Unfortunately, treatment options are limited due to the tumor's aggressive nature, typically resulting in fetal demise shortly after birth. Here, we present the sonographic and MRI findings of a congenital intracranial teratoma, reaching massive proportions and replacing the entire cerebral hemisphere.

Eukaryotic translation elongation factor 2 (eEF2), encoded by the gene EEF2, is an essential factor involved in the elongation phase of protein translation. A specific heterozygous missense variant (p.P596H) in EEF2 was originally identified in association with autosomal dominant adult-onset spinocerebellar ataxia-26 (SCA26). More recently, additional heterozygous missense variants in this gene have been described to cause a novel, childhood-onset neurodevelopmental disorder with benign external hydrocephalus. Herein, we report two unrelated individuals with a similar gene-disease correlation to support this latter observation. Patient 1 is a 7-year-old male with a previously reported, de novo missense variant (p.V28M) who has motor and speech delay, autism spectrum disorder, failure to thrive with relative macrocephaly, unilateral microphthalmia with coloboma and eczema. Patient 2 is a 4-year-old female with a novel de novo nonsense variant (p.Q145X) with motor and speech delay, hypotonia, macrocephaly with benign ventricular enlargement, and keratosis pilaris. These additional cases help to further expand the genotypic and phenotypic spectrum of this newly described EEF2-related neurodevelopmental syndrome.

Protein phosphatase 2 regulatory subunit B56δ related neurodevelopmental disorder (PPP2R5D‐related NDD) is largely caused by de novo heterozygous missense PPP2R5D variants. We report medical characteristics, longitudinal adaptive functioning, and in‐person neurological, motor, cognitive, and electroencephalogram (EEG) activity for PPP2R5D‐related NDD. Forty‐two individuals (median age 6 years, range = 0.8–25.3) with pathogenic/likely pathogenic PPP2R5D variants were assessed, and almost all variants were missense (97.6%) and de novo (85.7%). Common clinical symptoms were developmental delay, hypotonia, macrocephaly, seizures, autism, behavioral challenges, and sleep problems. The mean Gross motor functional measure‐66 was 60.2 ± 17.3% and the mean Revised upper limb module score was 25.9 ± 8.8. The Vineland‐3 adaptive behavior composite score (VABS‐3 ABC) at baseline was low (M = 61.7 ± 16.8). VABS‐3 growth scale value scores increased from baseline in all subdomains (range = 0.6–5.9) after a mean follow‐up of 1.3 ± 0.3 years. EEG beta and gamma power were negatively correlated with VABS‐3 score; p < 0.05. Individuals had a mean Quality‐of‐life inventory‐disability score of 74.7 ± 11.4. Twenty caregivers (80%) had a risk of burnout based on the Caregiver burden inventory. Overall, the most common clinical manifestations of PPP2R5D‐related NDD were impaired cognitive, adaptive function, and motor skills; and EEG activity was associated with adaptive functioning. This clinical characterization describes the natural history in preparation for clinical trials. [ABSTRACT FROM AUTHOR]

Background: Macrocephaly is described in almost 15% of children with Autism Spectrum Disorder (ASD). Relationships between head growth trajectories and clinical findings in ASD children show a high degree of variability, highlighting the complex heterogeneity of the disorder. Objectives: The aim of this study was to measure differences of the early growth trajectory of head circumference (HC) in children with ASD and macrocephaly compared to ASD normocephalic children, examining clinical correlates in the two groups of patients. Methods: HC data were collected from birth to 5 years of age in a sample of children with a confirmed diagnosis of ASD. Participants were classified into two groups: ASD macrocephaly (ASD-M, Z-scores =1.88 in at least two consecutive HC measurements), and ASD non-macrocephaly (ASD-N). Based on the distribution of HC measurements (Z-scores), five age groups were identified for the longitudinal study. Developmental and behavioral characteristics of the ASD-M children compared to the ASD-N group were compared by using standardized scores. Results: 20,8% of the children sample met criteria for macrocephaly. HC values became indicative of macrocephaly in the ASD-M group at the age range from 1 to 6 months, and persisted thereafter throughout the first five years of age. ASDM children showed significantly higher developmental quotients of Griffiths III B and D subscales compared to ASD-N group. No significant differences in the severity of ASD symptoms assessed by ADOS-2 were observed between ASD-M and ASD-N groups. Conclusion: In this study HC size from birth to 5 years links to accelerated HC growth rate as early as the first 6 months of age in children with ASD and macrocephaly, preceding the onset and diagnosis of ASD. We found that in early childhood, children with ASD-M may exhibit some advantages in language and social communication and emotional skills without differences in autism severity, when compared with age-matched normocephalic ASD children. Longitudinal analyses are required to catch-up prospectively possible relationships between head size as proxy measure of brain development and neuro-developmental and behavioral features in children with ASD. [ABSTRACT FROM AUTHOR]

Tubulinopathies are associated with malformations of cortical development but not Walker–Warburg Syndrome. Intensive monitoring of a Croatian infant presenting as Walker–Warburg Syndrome in utero began at 21 weeks due to increased growth of cerebral ventricles and foetal biparietal diameter. Monitoring continued until Caesarean delivery at 34 weeks where the infant was eutrophic. Clinical assessment of a progressive neurological disorder of unknown aetiology found a macrocephalic head and markedly hypoplastic genitalia with a micropenis. Neurological examination showed generalized hypotonia with very rare spontaneous movements, hypotonia-induced respiratory insufficiency and ventilator dependence, and generalized myoclonus intensifying during manipulation. With clinical features of hypotonia, lissencephaly, and brain malformations, Walker–Warburg Syndrome was suspected; however, eye anomalies were absent. Genetic trio analysis via whole-exome sequencing only identified a novel de novo mutation in the TUBA1A gene (NM_006009.4:c.848A>G; NP_006000.2:p.His283Arg) in the infant, who died at 2 months of age, as the likely cause. We report a previously unpublished, very rare heterozygous TUBA1A mutation with clinical features of macrocephaly and hypoplastic genitalia which have not previously been associated with the gene. The absence of eye phenotypes or mutations in Walker–Warburg-associated genes confirm this as not a new presentation of Walker–Warburg Syndrome but a novel TUBA1A tubulinopathy for neonatologists to be aware of. [ABSTRACT FROM AUTHOR]

Tatton–Brown–Rahman syndrome is a rare autosomal dominant hereditary disease caused by pathogenic variants in the DNMT3A gene, which is an important participant in epigenetic regulation, especially during embryonic development, and is highly expressed in all tissues. The main features of the syndrome are high growth, macrocephaly, intellectual disability, and facial dysmorphic features. We present a clinical case of Tatton–Brown–Rahman syndrome in a ten-year-old boy with macrocephaly with learning difficulties, progressive eye impairment, and fatigue suspected by a deep learning-based diagnosis assistance system, Face2Gene. The proband underwent whole-exome sequencing, which revealed a recurrent nonsense variant in the 12th exon of the DNMT3A, leading to the formation of a premature stop codon—NM_022552.5:c.1443C>A (p.Tyr481Ter), in a heterozygous state. This variant was not found in parents, confirming its de novo status. The patient case described here contributes to the understanding of the clinical diversity of Tatton–Brown–Raman syndrome with a mild clinical presentation that expands the phenotypic spectrum of the syndrome. We report the first recurrent nonsense variant in the DNMT3A gene, suggesting a mutational hot-spot. Differential diagnoses of this syndrome with Sotos syndrome, Weaver syndrome, and Cowden syndrome, as well as molecular confirmation, are extremely important, since the presence of certain types of pathogenic variants in the DNMT3A gene significantly increases the risk of developing acute myeloid leukemia. [ABSTRACT FROM AUTHOR]

Thanatophoric dysplasia is a lethal form of skeletal dysplasia seen in neonates. The word ‘thanatophoric’ is derived from the Greek word thanatophorus meaning death bringing. Thanatophoric dysplasia results from mutations within the Fibroblast Growth Factor Receptor 3 (FGFR3) gene which is located on chromosome 4p16.3. A female neonate with dysmorphic features such as macrocephaly, frontal bossing, periorbital swelling and depressed nasal bridge was delivered to a 35year old woman. The upper and lower limbs were short with excessive skin folds. A case of female neonate with thanatophoric dysplasia is hereby reported to raise awareness of this condition and to describe the features of thanatophoric dysplasia seen in this patient .

Tatton–Brown–Rahman syndrome is a rare autosomal dominant hereditary disease caused by pathogenic variants in the DNMT3A gene, which is an important participant in epigenetic regulation, especially during embryonic development, and is highly expressed in all tissues. The main features of the syndrome are high growth, macrocephaly, intellectual disability, and facial dysmorphic features. We present a clinical case of Tatton–Brown–Rahman syndrome in a ten-year-old boy with macrocephaly with learning difficulties, progressive eye impairment, and fatigue suspected by a deep learning-based diagnosis assistance system, Face2Gene. The proband underwent whole-exome sequencing, which revealed a recurrent nonsense variant in the 12th exon of the DNMT3A, leading to the formation of a premature stop codon—NM_022552.5:c.1443C>A (p.Tyr481Ter), in a heterozygous state. This variant was not found in parents, confirming its de novo status. The patient case described here contributes to the understanding of the clinical diversity of Tatton–Brown–Raman syndrome with a mild clinical presentation that expands the phenotypic spectrum of the syndrome. We report the first recurrent nonsense variant in the DNMT3A gene, suggesting a mutational hot-spot. Differential diagnoses of this syndrome with Sotos syndrome, Weaver syndrome, and Cowden syndrome, as well as molecular confirmation, are extremely important, since the presence of certain types of pathogenic variants in the DNMT3A gene significantly increases the risk of developing acute myeloid leukemia.

We present a case of Bannayan-Riley-Ruvalcaba syndrome (BRRS) diagnosed during the treatment of recurrent iron deficiency anemia (IDA). IDA is the most common hematological disorder in children and is often caused by dietary problem or obesity. However, in relatively rare cases, it is caused by gastrointestinal (GI) disease. BRRS is a rare genetic disorder characterized by macrocephaly, multiple noncancerous tumors, intestinal hamartomatous polyps, and penile freckling due to a defect in the PTEN gene. GI polyps can cause chronic GI bleeding, leading to IDA development. We recommend active GI evaluation, including esophagogastroduodenoscopy, for children with recurrent IDA.

Abstract Background Clinicians diagnosing autism rely on diagnostic criteria and instruments in combination with an implicit knowledge based on clinical expertise of the specific signs and presentations associated with the condition. This implicit knowledge influences how diagnostic criteria are interpreted, but it cannot be directly observed. Instead, insight into clinicians’ understanding of autism can be gained by investigating their diagnostic certainty. Modest correlations between the certainty of an autism diagnosis and symptom load have been previously reported. Here, we investigated the associations of diagnostic certainty with specific items of the ADOS as well as other clinical features including head circumference. Methods Phenotypic data from the Simons Simplex Collection was used to investigate clinical correlates of diagnostic certainty in individuals diagnosed with Autistic Disorder (n = 1511, age 4 to 18 years). Participants were stratified by the ADOS module used to evaluate them. We investigated how diagnostic certainty was associated with total ADOS scores, age, and ADOS module. We calculated the odds-ratios of being diagnosed with the highest possible certainty given the presence or absence of different signs during the ADOS evaluation. Associations between diagnostic certainty and other cognitive and clinical variables were also assessed. Results In each ADOS module, some items showed a larger association with diagnostic certainty than others. Head circumference was significantly higher for individuals with the highest certainty rating across all three ADOS modules. In turn, head circumference was positively correlated with some of the ADOS items that were associated with diagnostic certainty, and was negatively correlated with verbal/nonverbal IQ ratio among those assessed with ADOS module 2. Limitations The investigated cohort was heterogeneous, e.g. in terms of age, IQ, language level, and total ADOS score, which could impede the identification of associations that only exist in a subgroup of the population. The variability of the certainty ratings in the sample was low, limiting the power to identify potential associations with other variables. Additionally, the scoring of diagnostic certainty may vary between clinicians. Conclusion Some ADOS items may better capture the signs that are most associated with clinicians’ implicit knowledge of Autistic Disorder. If replicated in future studies, new diagnostic instruments with differentiated weighting of signs may be needed to better reflect this, possibly resulting in better specificity in standardized assessments.

Abstract Background Thousand and one amino-acid kinase 1 (TAOK1) encodes the MAP3K protein kinase TAO1, which has recently been displayed to be essential for neuronal maturation and cortical differentiation during early brain development. Heterozygous variants in TAOK1 have been reported in children with neurodevelopmental disorders, with or without macrocephaly, hypotonia and mild dysmorphic traits. Literature reports lack evidence of neuronal migration disorders in TAOK1 patients, although studies in animal models suggest this possibility. Case presentation We provide a clinical description of a child with a neurodevelopmental disorder due to a novel TAOK1 truncating variant, whose brain magnetic resonance imaging displays periventricular nodular heterotopia. Conclusions To our knowledge, this is the first report of a neuronal migration disorder in a patient with a TAOK1-related neurodevelopmental disorder, thus supporting the hypothesized pathogenic mechanisms of TAOK1 defects.

Macrocephaly, characterized by an abnormally large head circumference, often co-occurs with distinctive finger changes, presenting a diagnostic challenge for clinicians. This review aims to provide a current synthetic overview of the main acquired and genetic etiologies associated with macrocephaly and finger changes. The genetic cause encompasses several categories of diseases, including bone marrow expansion disorders, skeletal dysplasias, ciliopathies, inherited metabolic diseases, RASopathies, and overgrowth syndromes. Furthermore, autoimmune and autoinflammatory diseases are also explored for their potential involvement in macrocephaly and finger changes. The intricate genetic mechanisms involved in the formation of cranial bones and extremities are multifaceted. An excess in growth may stem from disruptions in the intricate interplays among the genetic, epigenetic, and hormonal factors that regulate human growth. Understanding the underlying cellular and molecular mechanisms is important for elucidating the developmental pathways and biological processes that contribute to the observed clinical phenotypes. The review provides a practical approach to delineate causes of macrocephaly and finger changes, facilitate differential diagnosis and guide for the appropriate etiological framework. Early recognition contributes to timely intervention and improved outcomes for affected individuals. [ABSTRACT FROM AUTHOR]

Mutations in CHD8 are one of the highest genetic risk factors for autism spectrum disorder. Studies in mice that investigate underlying mechanisms have shown Chd8 haploinsufficient mice display some trait disruptions that mimic clinical phenotypes, although inconsistencies have been reported in some traits across different models on the same strain background. One source of variation across studies may be the impact of Chd8 haploinsufficiency on maternal‐offspring interactions. While differences in maternal care as a function of Chd8 genotype have not been studied directly, a previous study showed that pup survival was reduced when reared by Chd8 heterozygous dams compared with wild‐type (WT) dams, suggesting altered maternal care as a function of Chd8 genotype. Through systematic observation of the C57BL/6 strain, we first determined the impact of Chd8 haploinsufficiency in the offspring on WT maternal care frequencies across preweaning development. We next determined the impact of maternal Chd8 haploinsufficiency on pup care. Compared with litters with all WT offspring, WT dams exhibited less frequent maternal behaviors toward litters consisting of offspring with mixed Chd8 genotypes, particularly during postnatal week 1. Dam Chd8 haploinsufficiency decreased litter survival and increased active maternal care also during postnatal week 1. Determining the impact of Chd8 haploinsufficiency on early life experiences provides an important foundation for interpreting offspring outcomes and determining mechanisms that underlie heterogeneous phenotypes. [ABSTRACT FROM AUTHOR]

Background: Thousand and one amino-acid kinase 1 (TAOK1) encodes the MAP3K protein kinase TAO1, which has recently been displayed to be essential for neuronal maturation and cortical differentiation during early brain development. Heterozygous variants in TAOK1 have been reported in children with neurodevelopmental disorders, with or without macrocephaly, hypotonia and mild dysmorphic traits. Literature reports lack evidence of neuronal migration disorders in TAOK1 patients, although studies in animal models suggest this possibility. Case presentation: We provide a clinical description of a child with a neurodevelopmental disorder due to a novel TAOK1 truncating variant, whose brain magnetic resonance imaging displays periventricular nodular heterotopia. Conclusions: To our knowledge, this is the first report of a neuronal migration disorder in a patient with a TAOK1-related neurodevelopmental disorder, thus supporting the hypothesized pathogenic mechanisms of TAOK1 defects. [ABSTRACT FROM AUTHOR]

BackgroundMacrocephaly is described in almost 15% of children with Autism Spectrum Disorder (ASD). Relationships between head growth trajectories and clinical findings in ASD children show a high degree of variability, highlighting the complex heterogeneity of the disorder.ObjectivesThe aim of this study was to measure differences of the early growth trajectory of head circumference (HC) in children with ASD and macrocephaly compared to ASD normocephalic children, examining clinical correlates in the two groups of patients.MethodsHC data were collected from birth to 5 years of age in a sample of children with a confirmed diagnosis of ASD. Participants were classified into two groups: ASD macrocephaly (ASD-M, Z-scores ≥1.88 in at least two consecutive HC measurements), and ASD non-macrocephaly (ASD-N). Based on the distribution of HC measurements (Z-scores), five age groups were identified for the longitudinal study. Developmental and behavioral characteristics of the ASD-M children compared to the ASD-N group were compared by using standardized scores.Results20,8% of the children sample met criteria for macrocephaly. HC values became indicative of macrocephaly in the ASD-M group at the age range from 1 to 6 months, and persisted thereafter throughout the first five years of age. ASD-M children showed significantly higher developmental quotients of Griffiths III B and D subscales compared to ASD-N group. No significant differences in the severity of ASD symptoms assessed by ADOS-2 were observed between ASD-M and ASD-N groups.ConclusionIn this study HC size from birth to 5 years links to accelerated HC growth rate as early as the first 6 months of age in children with ASD and macrocephaly, preceding the onset and diagnosis of ASD. We found that in early childhood, children with ASD-M may exhibit some advantages in language and social communication and emotional skills without differences in autism severity, when compared with age-matched normocephalic ASD children. Longitudinal analyses are required to catch-up prospectively possible relationships between head size as proxy measure of brain development and neuro-developmental and behavioral features in children with ASD.

BackgroundGLI3 encodes a zinc finger transcription factor that plays a role in the sonic hedgehog pathway. Germline pathogenic GLI3 variants are associated with Greig cephalopolysyndactyly and Pallister-Hall syndromes, two syndromes involving brain malformation and polydactyly.MethodsWe identified patients with pathogenic GLI3 variants and brain malformations in the absence of polydactyly or other skeletal malformation.ResultsTwo patients were identified. Patient #1 is a 4-year-old boy with hypotonia and global developmental delay. Brain MRI showed a focal cortical dysplasia, but he had no history of seizures. Genetic testing identified a de novo likely pathogenic GLI3 variant: c.4453A>T, p.Asn1485Tyr. Patient #2 is a 4-year-old boy with hypotonia, macrocephaly, and global developmental delay. His brain MRI showed partial agenesis of the corpus callosum, dilatation of the right lateral ventricle, and absent hippocampal commissure. Genetic testing identified a de novo pathogenic GLI3 variant: c.4236_4237del, p.Gln1414AspfsTer21. Neither patient had polydactyly or any apparent skeletal abnormality.ConclusionsThese patients widen the spectrum of clinical features that may be associated with GLI3 pathogenic variants to include hypotonia, focal cortical dysplasia, and other brain malformations, in the absence of apparent skeletal malformation. Further study is needed to determine if GLI3 pathogenic variants are a more common cause of focal cortical dysplasia or corpus callosum agenesis than presently recognized.

Background: Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare, inherited disorder that causes epilepsy, intellectual disorders, and early onset macrocephaly. MLC1 has been identified as a main pathogenic gene. Methods: Clinical data such as magnetic resonance imaging (MRI), routine blood tests, and physical examinations were collected from proband. Trio whole‐exome sequencing (WES) of the family was performed, and all variants with a minor allele frequency (<0.01) in the exon and canonical splicing sites were selected for further pathogenic evaluation. Candidate variants were validated using Sanger sequencing. Results: Here, we report a new homozygous variant identified in two children from the same family in the MLC1 gene [NM_015166.4: c.838_843delinsATTTTA, (p.Ser280_Phe281delinsIleLeu)]. This variant is classified as variant of uncertain significance (VUS) according to the ACMG guidelines. Further experiments demonstrate that the newly identified variant causes a decrease of MLC1 protein levels when expressed in a heterologous expression system. Conclusion: Our case expands on this genetic variation and provides new evidence for the clinical diagnosis of MLC1‐related MLC. [ABSTRACT FROM AUTHOR]

Cyclin D2 (CCND2) stabilization underpins a range of macrocephaly-associated disorders through mutation of CCND2 or activating mutations in upstream genes encoding PI3K-AKT pathway components. Here, we describe three individuals with overlapping macrocephaly-associated phenotypes who carry the same recurrent de novo c.179G>A (p.Arg60Gln) variant in Myc-associated factor X (MAX). The mutation, located in the b-HLH-LZ domain, causes increased intracellular CCND2 through increased transcription but it does not cause stabilization of CCND2. We show that the purified b-HLH-LZ domain of MAXArg60Gln (Max∗Arg60Gln) binds its target E-box sequence with a lower apparent affinity. This leads to a more efficient heterodimerization with c-Myc resulting in an increase in transcriptional activity of c-Myc in individuals carrying this mutation. The recent development of Omomyc-CPP, a cell-penetrating b-HLH-LZ-domain c-Myc inhibitor, provides a possible therapeutic option for MAXArg60Gln individuals, and others carrying similar germline mutations resulting in dysregulated transcriptional c-Myc activity. Harris et al. describe three individuals with overlapping macrocephaly-associated phenotypes carrying a recurrent de novo c.179G>A (p.Arg60Gln) variant in Myc-associated factor X (MAX). MAXArg60Gln binds its target E-box sequence with a lower affinity, meaning more efficient heterodimerization with c-Myc and dysregulated transcriptional activity. c-Myc inhibitors provide a possible therapeutic option for individuals carrying this variant. [ABSTRACT FROM AUTHOR]

Key Clinical Message: We report the first multigenerational family with NFIA‐related disorder from a missense variant. This case highlights the condition's phenotypic variability and the need for genetic testing when an initial diagnosis fails to explain all symptoms. [ABSTRACT FROM AUTHOR]

Abstract Background Macrocephaly is present in 2.3% of children with important neurosurgical conditions in the differential diagnosis. The objective of this study was to identify clinical associations with actionable imaging findings among children with head imaging for macrocephaly. Methods We conducted a case-control study of head imaging studies ordered for macrocephaly among children 24 months and younger in a multistate children’s health system. Four neurosurgeons reviewed the images, determining cases to be a ‘concern’ if neurosurgical follow-up or intervention was indicated. Electronic health records were reviewed to collect patient-level data and to determine if surgery was performed. Controls were matched 3:1 to cases of ‘concern’ in a multivariate model using conditional logistic regression. Results In the study sample (n = 1293), 46 (4%) were concern cases, with 15 (1%) requiring surgery. Significant clinical factors associated with neurosurgical concern were bulging fontanel [aOR 7.47, (95% CI: 2.28–24.44), P

Abstract Background Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare, inherited disorder that causes epilepsy, intellectual disorders, and early onset macrocephaly. MLC1 has been identified as a main pathogenic gene. Methods Clinical data such as magnetic resonance imaging (MRI), routine blood tests, and physical examinations were collected from proband. Trio whole‐exome sequencing (WES) of the family was performed, and all variants with a minor allele frequency (

Key Clinical Message We report the first multigenerational family with NFIA‐related disorder from a missense variant. This case highlights the condition's phenotypic variability and the need for genetic testing when an initial diagnosis fails to explain all symptoms.

Background: Macrocephaly is present in 2.3% of children with important neurosurgical conditions in the differential diagnosis. The objective of this study was to identify clinical associations with actionable imaging findings among children with head imaging for macrocephaly. Methods: We conducted a case-control study of head imaging studies ordered for macrocephaly among children 24 months and younger in a multistate children's health system. Four neurosurgeons reviewed the images, determining cases to be a 'concern' if neurosurgical follow-up or intervention was indicated. Electronic health records were reviewed to collect patient-level data and to determine if surgery was performed. Controls were matched 3:1 to cases of 'concern' in a multivariate model using conditional logistic regression. Results: In the study sample (n = 1293), 46 (4%) were concern cases, with 15 (1%) requiring surgery. Significant clinical factors associated with neurosurgical concern were bulging fontanel [aOR 7.47, (95% CI: 2.28–24.44), P < 0.001], prematurity [aOR 21.26, (95% CI: 3.76–120.21), P < 0.001], any delay [aOR 2.67, (95% CI: 1.13–6.27), P = 0.03], and head-weight Z-score difference (W_diff, defined as the difference between the Z-scores of head circumference and weight) [aOR 1.70, (95% CI: 1.22–2.37), P = 0.002]. Conclusions: Head imaging for macrocephaly identified few patients with findings of concern and fewer requiring surgery. A greater head-weight Z-score difference appears to represent a novel risk factor for neurosurgical follow-up or intervention. [ABSTRACT FROM AUTHOR]

KPTN -related disorder is an autosomal recessive disorder associated with germline variants in KPTN (previously known as kaptin), a component of the mTOR regulatory complex KICSTOR. To gain further insights into the pathogenesis of KPTN -related disorder, we analysed mouse knockout and human stem cell KPTN loss-of-function models. Kptn −/− mice display many of the key KPTN -related disorder phenotypes, including brain overgrowth, behavioural abnormalities, and cognitive deficits. By assessment of affected individuals, we have identified widespread cognitive deficits (n = 6) and postnatal onset of brain overgrowth (n = 19). By analysing head size data from their parents (n = 24), we have identified a previously unrecognized KPTN dosage-sensitivity, resulting in increased head circumference in heterozygous carriers of pathogenic KPTN variants. Molecular and structural analysis of Kptn −/− mice revealed pathological changes, including differences in brain size, shape and cell numbers primarily due to abnormal postnatal brain development. Both the mouse and differentiated induced pluripotent stem cell models of the disorder display transcriptional and biochemical evidence for altered mTOR pathway signalling, supporting the role of KPTN in regulating mTORC1. By treatment in our KPTN mouse model, we found that the increased mTOR signalling downstream of KPTN is rapamycin sensitive, highlighting possible therapeutic avenues with currently available mTOR inhibitors. These findings place KPTN -related disorder in the broader group of mTORC1-related disorders affecting brain structure, cognitive function and network integrity. [ABSTRACT FROM AUTHOR]

Metabolites of the Amyloid-β precursor protein (APP) proteolysis may underlie brain overgrowth in Autism Spectrum Disorder (ASD). We have found elevated APP metabolites (total APP, secreted (s) APPα, and α-secretase adamalysins in the plasma and brain tissue of children with ASD). In this review, we highlight several lines of evidence supporting APP metabolites’ potential contribution to macrocephaly in ASD. First, APP appears early in corticogenesis, placing APP in a prime position to accelerate growth in neurons and glia. APP metabolites are upregulated in neuroinflammation, another potential contributor to excessive brain growth in ASD. APP metabolites appear to directly affect translational signaling pathways, which have been linked to single gene forms of syndromic ASD (Fragile X Syndrome, PTEN, Tuberous Sclerosis Complex). Finally, APP metabolites, and microRNA, which regulates APP expression, may contribute to ASD brain overgrowth, particularly increased white matter, through ERK receptor activation on the PI3K/Akt/mTOR/Rho GTPase pathway, favoring myelination. [ABSTRACT FROM AUTHOR]

Copyright of Revista Pediatría de Atención Primaria is the property of LUA Ediciones 3.0 S.L. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Metabolites of the Amyloid-β precursor protein (APP) proteolysis may underlie brain overgrowth in Autism Spectrum Disorder (ASD). We have found elevated APP metabolites (total APP, secreted (s) APPα, and α-secretase adamalysins in the plasma and brain tissue of children with ASD). In this review, we highlight several lines of evidence supporting APP metabolites’ potential contribution to macrocephaly in ASD. First, APP appears early in corticogenesis, placing APP in a prime position to accelerate growth in neurons and glia. APP metabolites are upregulated in neuroinflammation, another potential contributor to excessive brain growth in ASD. APP metabolites appear to directly affect translational signaling pathways, which have been linked to single gene forms of syndromic ASD (Fragile X Syndrome, PTEN, Tuberous Sclerosis Complex). Finally, APP metabolites, and microRNA, which regulates APP expression, may contribute to ASD brain overgrowth, particularly increased white matter, through ERK receptor activation on the PI3K/Akt/mTOR/Rho GTPase pathway, favoring myelination.

Introduction: Shashi-Pena syndrome is characterized by macrocephaly, intellectual disability and epilepsy, which is confirmed by genetic studies. Case presentation: 15-year-old male patient, with a history of being preterm at 36 weeks of gestation, weight 1,900 grams. From birth he was detected with peripheral hypotonia and swallowing problems. At the age of three he presented status epilepticus. Currently with learning difficulties. Physical examination revealed macrocephaly and facial anomalies. A skull MRI identified septum cavum vergae. IQ was 53 points. In a molecular study, a variant in the ASXL2 gene, c.2843C>T (p.Ala948Val), was reported. Conclusions: variants in the ASXL2 gene are associated with Shashi-Pena syndrome. The diagnosis of this syndrome could result from the detection of patients with macrocephaly associated with other comorbidities. [ABSTRACT FROM AUTHOR]

PurposeDetermination of genotypic/phenotypic features of GATAD2B-associated neurodevelopmental disorder (GAND).MethodsFifty GAND subjects were evaluated to determine consistent genotypic/phenotypic features. Immunoprecipitation assays utilizing in vitro transcription-translation products were used to evaluate GATAD2B missense variants' ability to interact with binding partners within the nucleosome remodeling and deacetylase (NuRD) complex.ResultsSubjects had clinical findings that included macrocephaly, hypotonia, intellectual disability, neonatal feeding issues, polyhydramnios, apraxia of speech, epilepsy, and bicuspid aortic valves. Forty-one novelGATAD2B variants were identified with multiple variant types (nonsense, truncating frameshift, splice-site variants, deletions, and missense). Seven subjects were identified with missense variants that localized within two conserved region domains (CR1 or CR2) of the GATAD2B protein. Immunoprecipitation assays revealed several of these missense variants disrupted GATAD2B interactions with its NuRD complex binding partners.ConclusionsA consistent GAND phenotype was caused by a range of genetic variants in GATAD2B that include loss-of-function and missense subtypes. Missense variants were present in conserved region domains that disrupted assembly of NuRD complex proteins. GAND's clinical phenotype had substantial clinical overlap with other disorders associated with the NuRD complex that involve CHD3 and CHD4, with clinical features of hypotonia, intellectual disability, cardiac defects, childhood apraxia of speech, and macrocephaly.

Abstract Background Modern human brains and skull shapes differ from other hominids. Brain growth disorders as micro- (ASPM, MCPH1) and macrocephaly (NFIX, GLI3) have been highlighted as relevant for the evolution in humans due to the impact in early brain development. Genes associated with macrocephaly have been reported to cause this change, for example NSD1 which causes Sotos syndrome. Results In this study we performed a systematic literature review, located the reported variants associated to Sotos syndrome along the gene domains, compared the sequences with close primates, calculated their similarity, Ka/Ks ratios, nucleotide diversity and selection, and analyzed the sequence and structural conservation with distant primates. We aimed to understand if NSD1 in humans differs from other primates since the evolution of NSD1 has not been analyzed in primates, nor if the localization of the mutations is limited to humans. Our study found that most variations causing Sotos syndrome are in exon 19, 22 and 10. In the primate comparison we did not detect Ka/Ks ratios > 1, but a high nucleotide diversity with non-synonymous variations in exons 10, 5, 9, 11 and 23, and sites under episodic selection in exon 5 and 23, and human, macaque/colobus/tarsier/galago and tarsier/lemur/colobus. Most of the domains are conserved in distant primates with a particular progressive development from a simple PWWP1 in O. garnetti to a complex structure in Human. Conclusion NSD1 is a chromatin modifier that suggests that the selection could influence brain development during modern human evolution and is not present in other primates; however, nowadays the nucleotide diversity is associated with Sotos syndrome.

Abstract Background 2q37 deletion syndrome is a rare autosomal dominant disorder caused by deletions in the 2q37 cytobands leading to developmental delay, intellectual disability, behavioral abnormalities and dysmorphic craniofacial features with more than 115 patients described worldwide. Case presentation We describe a Colombian 3-year-old patient with verbal communication delay, umbilical hernia, facial dysmorphic features, hypotonia, and macrocephaly with normal magnetic resonance imaging. Microarray-based comparative genomic hybridization revealed a 5.9 Mb deletion in the 2q37.2 and 2q37.3 regions, eliminating 60 protein-coding genes in one of her chromosomes 2 and allowing the diagnosis of 2q37 deletion syndrome in this patient. Therapeutic interventions so far were the surgical correction of the umbilical hernia. Conclusions Genetic tests are important tools for the diagnosis of clinically complex and infrequent conditions but also for timely diagnosis that allows appropriate surveillance, interventions, and genetic counseling. This case also provides information for expanding the phenotypical and genetic characterization of 2q37 deletion syndrome.

Phelan–McDermid syndrome (PMS) is a multisystem disorder that is associated with deletions of the 22q13 genomic region or pathogenic variants in the SHANK3 gene. Notable features include developmental issues, absent or delayed speech, neonatal hypotonia, seizures, autism or autistic traits, gastrointestinal problems, renal abnormalities, dolichocephaly, and both macro- and microcephaly. Assessment of the genetic factors that are responsible for abnormal head size in PMS has been hampered by small sample sizes as well as a lack of attention to these features. Therefore, this study was conducted to investigate the relationship between head size and genes on chromosome 22q13. A review of the literature was conducted to identify published cases of 22q13 deletions with information on head size to conduct a pooled association analysis. Across 56 studies, we identified 198 cases of PMS with defined deletion sizes and head size information. A total of 33 subjects (17%) had macrocephaly, 26 (13%) had microcephaly, and 139 (70%) were normocephalic. Individuals with macrocephaly had significantly larger genomic deletions than those with microcephaly or normocephaly (p < 0.0001). A genomic region on 22q13.31 was found to be significantly associated with macrocephaly with CELSR1, GRAMD4, and TBCD122 suggested as candidate genes. Investigation of these genes will aid the understanding of head and brain development. [ABSTRACT FROM AUTHOR]

Introduction: Luscan-Lumish syndrome (LLS) is currently recognized as a rarelyobserved condition featured with overgrowth, macrocephaly, obesity, type I Chiari malformation, and linguistic retardation. So far, there have been only a few LLS cases registered worldwide, but with none of them reported from China. To acquire a deeper understanding on the clinical and genetic features of this disease, a Chinese boy with LLS caused by a heterozygous variant in SETD2 gene was investigated in the present study. Methods: The patient was clinically examined and the medical history of his family was collected. Genetic testing was performed to determine the genetic etiology. Results: The proband was a boy aged 5-year-7-month-old, who was referred to our hospital due to "being a slow learner in kindergarten". The child had a history of delayed motor and language development in comparison to his peers. After admission, physical examination revealed tall stature and macrocephaly as the major manifestation, in addition to a relatively lower rating in intelligence assessment as well as abnormal MRI images showing a slightly shorter corpus callosum accompanied by a mildly thinner corpus callosum body. Whole exome sequencing (WES) revealed a heterozygous c.2514_2516delTAG (p.Ser838del) variant in SETD2 gene, which was subsequently identified as a novel de novo variant. According to the standardized genetic variant classification published by the American College of Medical Genetics and Genomics (ACMG), the variant, with a pathogenicity analysis result indicating PS2 + PM2_Supporting + PM4, was determined to be likely pathogenic. Through literature review, the clinical phenotypes of the 15 LLS cases were summarized, including 8 cases of overgrowth (53%), 13 cases of macrocephaly (87%), 11 cases of developmental delay (73%), 8 cases of autism (53%), and 7 cases of special facial features (47%). Besides, abnormal craniocerebral MRI findings were noticed in 7 cases. Despite that the mutation sites of the 15 patients varied from case to case, they showed a uniformly distributed pattern throughout the whole SETD2 gene, including 5 missense mutations, 5 frameshift mutations and 5 non-sense mutations. Conclusion: LLS, not having been recognized till recent years, is identified as an autosomal dominant syndrome triggered by SETD2 gene mutation. As the first report of LLS in China, the case in our study was proved to be associated with a unique type of SETD2 gene mutation that has never been reported previously, which is believed to enrich the mutation spectrum of SETD2 gene and also, deepening the clinicians' understanding on the disease. [ABSTRACT FROM AUTHOR]

Biallelic variants in the kaptin gene KPTN were identified recently in individuals with a novel syndrome referred to as autosomal recessive intellectual developmental disorder 41 (MRT41). MRT41 is characterized by developmental delay, predominantly in language development, behavioral abnormalities, and epilepsy. Only about 15 affected individuals have been described in the literature, all with primary or secondary macrocephaly. Using exome sequencing, we identified three different biallelic variants in KPTN in five affected individuals from three unrelated families. In total, two KPTN variants were already reported as a loss of function variants. A novel splice site variant in KPTN was detected in two unrelated families of this study. The core phenotype with neurodevelopment delay was present in all patients. However, macrocephaly was not present in at least one patient. In total, two patients exhibited developmental and epileptic encephalopathies with generalized tonic-clonic seizures that were drug-resistant in one of them. Thus, we further delineate the KPTN-related syndrome, especially emphasizing the severity of epilepsy phenotypes and difficulties in treatment in patients of our cohort. [ABSTRACT FROM AUTHOR]

Fetal brain tumors are a rare entity with an overall guarded prognosis. About 10% of congenital brain tumors are diagnosed during fetal life. They differ from the postnatally encountered pediatric brain tumors with respect to location and tumor type. Fetal brain tumors can be benign or malignant and infiltrate or displace adjacent brain structures. Due to their high mitotic rate, they can show rapid growth. Outcome depends on age of diagnosis, size, and histological tumor type. Findings like polyhydramnios and macrocephaly encountered on routine ultrasound are frequently associated. Detailed prenatal anomaly scan and subsequent fetal magnetic resonance imaging (MRI) may identify the brain tumor and its severity. Both maternal and fetal prognosis should be included in prenatal counselling and decision making. [ABSTRACT FROM AUTHOR]

PPP2R1A-related neurodevelopmental disorder (NDD) is expressed with autosomal dominant inheritance and is typically caused by a pathogenic de novo PPP2R1A mutation. It is characterized by the predominant features of hypotonia, developmental delay, moderate-to-severe intellectual disability, agenesis of corpus callosum (ACC), ventriculomegaly, and dysmorphic features; however, none of these anomalies have been diagnosed prenatally. We report on the prenatal diagnosis of PPP2R1A-related NDD in two fetuses by whole exome sequencing. Fetus 1 had partial ACC and severe lateral ventriculomegaly; the pathogenic heterozygous c.544C > T (p. Arg182Trp) de novo missense variant in PPP2R1A was detected. Fetus 2 had severe enlargement of the lateral and third ventricles and macrocephaly; they showed a heterozygous likely pathogenic mutation in PPP2R1A gene (c.547C > T, p. Arg183Trp). Both variants were de novo. This was the first study to use trio WES to prenatally analyze fetuses with PPP2R1A variants. Prenatal diagnosis will not only expand the fetal phenotype of this rare genetic condition but also allow for an appropriate counseling of prospective parents regarding pregnancy outcomes. [ABSTRACT FROM AUTHOR]

Background: Modern human brains and skull shapes differ from other hominids. Brain growth disorders as micro- (ASPM, MCPH1) and macrocephaly (NFIX, GLI3) have been highlighted as relevant for the evolution in humans due to the impact in early brain development. Genes associated with macrocephaly have been reported to cause this change, for example NSD1 which causes Sotos syndrome. Results: In this study we performed a systematic literature review, located the reported variants associated to Sotos syndrome along the gene domains, compared the sequences with close primates, calculated their similarity, Ka/Ks ratios, nucleotide diversity and selection, and analyzed the sequence and structural conservation with distant primates. We aimed to understand if NSD1 in humans differs from other primates since the evolution of NSD1 has not been analyzed in primates, nor if the localization of the mutations is limited to humans. Our study found that most variations causing Sotos syndrome are in exon 19, 22 and 10. In the primate comparison we did not detect Ka/Ks ratios > 1, but a high nucleotide diversity with non-synonymous variations in exons 10, 5, 9, 11 and 23, and sites under episodic selection in exon 5 and 23, and human, macaque/colobus/tarsier/galago and tarsier/lemur/colobus. Most of the domains are conserved in distant primates with a particular progressive development from a simple PWWP1 in O. garnetti to a complex structure in Human. Conclusion: NSD1 is a chromatin modifier that suggests that the selection could influence brain development during modern human evolution and is not present in other primates; however, nowadays the nucleotide diversity is associated with Sotos syndrome. [ABSTRACT FROM AUTHOR]

Macrocephaly frequently occurs in single-gene disorders affecting the PI3K-AKT-MTOR pathway; however, epigenetic mutations, mosaicism, and copy number variations (CNVs) are emerging relevant causative factors, revealing a higher genetic heterogeneity than previously expected. The aim of this study was to investigate the role of rare CNVs in patients with macrocephaly and review genomic loci and known genes. We retrieved from the DECIPHER database de novo <500 kb CNVs reported on patients with macrocephaly; in four cases, a candidate gene for macrocephaly could be pinpointed: a known microcephaly gene–TRAPPC9, and three genes based on their functional roles–RALGAPB, RBMS3, and ZDHHC14. From the literature review, 28 pathogenic CNV genomic loci and over 300 known genes linked to macrocephaly were gathered. Among the genomic regions, 17 CNV loci (~61%) exhibited mirror phenotypes, that is, deletions and duplications having opposite effects on head size. Identifying structural variants affecting head size can be a preeminent source of information about pathways underlying brain development. In this study, we reviewed these genes and recurrent CNV loci associated with macrocephaly, as well as suggested novel potential candidate genes deserving further studies to endorse their involvement with this phenotype. [ABSTRACT FROM AUTHOR]

The NFIA (nuclear factor I/A) gene encodes for a transcription factor belonging to the nuclear factor I family and has key roles in various embryonic differentiation pathways. In humans, NFIA is the major contributor to the phenotypic traits of "Chromosome 1p32p31 deletion syndrome". We report on two new cases with deletions involving NFIA without any other pathogenic protein-coding gene alterations. A cohort of 24 patients with NFIA haploinsufficiency as the sole anomaly was selected by reviewing the literature and public databases in order to analyze all clinical features reported and their relative frequencies. This process was useful because it provided an overall picture of the phenotypic outcome of NFIA haploinsufficiency and helped to define a cluster of phenotypic traits that can facilitate clinicians in identifying affected patients. NFIA haploinsufficiency can be suspected by a careful observation of the dysmorphisms (macrocephaly, craniofacial, and first-finger anomalies), and this potential diagnosis is strengthened by the presence of intellectual and developmental disabilities or other neurodevelopmental disorders. Further clues of NFIA haploinsufficiency can be provided by instrumental tests such as MRI and kidney urinary tract ultrasound and confirmed by genetic testing. [ABSTRACT FROM AUTHOR]

ObjectiveTo compare the proportion of female and male fetuses classified as microcephalic (head circumference [HC] 97th percentile) by commonly used sex-neutral growth curves.MethodsFor fetuses evaluated at a single center, we retrospectively determined the percentile of the first fetal HC measurement between 16 and 0/7 and 21–6/7 weeks using the Hadlock, Intergrowth-21st, and NICHD growth curves. The association between sex and the likelihood of being classified as microcephalic or macrocephalic was evaluated with logistic regression.ResultsFemale fetuses (n = 3,006) were more likely than male fetuses (n = 3,186) to be classified as microcephalic using the Hadlock (0.4% male, 1.4% female; odds ratio female vs. male 3.7, 95% CI [1.9, 7.0], p

Biallelic variants in the kaptin gene KPTN were identified recently in individuals with a novel syndrome referred to as autosomal recessive intellectual developmental disorder 41 (MRT41). MRT41 is characterized by developmental delay, predominantly in language development, behavioral abnormalities, and epilepsy. Only about 15 affected individuals have been described in the literature, all with primary or secondary macrocephaly. Using exome sequencing, we identified three different biallelic variants in KPTN in five affected individuals from three unrelated families. In total, two KPTN variants were already reported as a loss of function variants. A novel splice site variant in KPTN was detected in two unrelated families of this study. The core phenotype with neurodevelopment delay was present in all patients. However, macrocephaly was not present in at least one patient. In total, two patients exhibited developmental and epileptic encephalopathies with generalized tonic-clonic seizures that were drug-resistant in one of them. Thus, we further delineate the KPTN-related syndrome, especially emphasizing the severity of epilepsy phenotypes and difficulties in treatment in patients of our cohort.

The nuclear factor I (NFI) family of transcription factors play an important role in normal development of multiple organs. Three NFI family members are highly expressed in the brain, and deletions or sequence variants in two of these, NFIA and NFIX, have been associated with intellectual disability (ID) and brain malformations. NFIB, however, has not previously been implicated in human disease. Here, we present a cohort of 18 individuals with mild ID and behavioral issues who are haploinsufficient for NFIB. Ten individuals harbored overlapping microdeletions of the chromosomal 9p23-p22.2 region, ranging in size from 225 kb to 4.3 Mb. Five additional subjects had point sequence variations creating a premature termination codon, and three subjects harbored single-nucleotide variations resulting in an inactive protein as determined using an in vitro reporter assay. All individuals presented with additional variable neurodevelopmental phenotypes, including muscular hypotonia, motor and speech delay, attention deficit disorder, autism spectrum disorder, and behavioral abnormalities. While structural brain anomalies, including dysgenesis of corpus callosum, were variable, individuals most frequently presented with macrocephaly. To determine whether macrocephaly could be a functional consequence of NFIB disruption, we analyzed a cortex-specific Nfib conditional knockout mouse model, which is postnatally viable. Utilizing magnetic resonance imaging and histology, we demonstrate that Nfib conditional knockout mice have enlargement of the cerebral cortex but preservation of overall brain structure and interhemispheric connectivity. Based on our findings, we propose that haploinsufficiency of NFIB causes ID with macrocephaly.