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Contains fulltext : 243955.pdf (Publisher’s version ) (Open Access) PURPOSE: Pathogenic variants in SETD1B have been associated with a syndromic neurodevelopmental disorder including intellectual disability, language delay, and seizures. To date, clinical features have been described for 11 patients with (likely) pathogenic SETD1B sequence variants. This study aims to further delineate the spectrum of the SETD1B-related syndrome based on characterizing an expanded patient cohort. METHODS: We perform an in-depth clinical characterization of a cohort of 36 unpublished individuals with SETD1B sequence variants, describing their molecular and phenotypic spectrum. Selected variants were functionally tested using in vitro and genome-wide methylation assays. RESULTS: Our data present evidence for a loss-of-function mechanism of SETD1B variants, resulting in a core clinical phenotype of global developmental delay, language delay including regression, intellectual disability, autism and other behavioral issues, and variable epilepsy phenotypes. Developmental delay appeared to precede seizure onset, suggesting SETD1B dysfunction impacts physiological neurodevelopment even in the absence of epileptic activity. Males are significantly overrepresented and more severely affected, and we speculate that sex-linked traits could affect susceptibility to penetrance and the clinical spectrum of SETD1B variants. CONCLUSION: Insights from this extensive cohort will facilitate the counseling regarding the molecular and phenotypic landscape of newly diagnosed patients with the SETD1B-related syndrome.

In pleiotropic diseases, multiple organ systems are affected causing a variety of clinical manifestations. Here, we report a pleiotropic disorder with a unique constellation of neurological, endocrine, exocrine, and haematological findings that is caused by biallelic MADD variants. MADD, the mitogen-activated protein kinase (MAPK) activating death domain protein, regulates various cellular functions, such as vesicle trafficking, activity of the Rab3 and Rab27 small GTPases, tumour necrosis factor-α (TNF-α)-induced signalling and prevention of cell death. Through national collaboration and GeneMatcher, we collected 23 patients with 21 different pathogenic MADD variants identified by next-generation sequencing. We clinically evaluated the series of patients and categorized the phenotypes in two groups. Group 1 consists of 14 patients with severe developmental delay, endo- and exocrine dysfunction, impairment of the sensory and autonomic nervous system, and haematological anomalies. The clinical course during the first years of life can be potentially fatal. The nine patients in Group 2 have a predominant neurological phenotype comprising mild-to-severe developmental delay, hypotonia, speech impairment, and seizures. Analysis of mRNA revealed multiple aberrant MADD transcripts in two patient-derived fibroblast cell lines. Relative quantification of MADD mRNA and protein in fibroblasts of five affected individuals showed a drastic reduction or loss of MADD. We conducted functional tests to determine the impact of the variants on different pathways. Treatment of patient-derived fibroblasts with TNF-α resulted in reduced phosphorylation of the extracellular signal-regulated kinases 1 and 2, enhanced activation of the pro-apoptotic enzymes caspase-3 and -7 and increased apoptosis compared to control cells. We analysed internalization of epidermal growth factor in patient cells and identified a defect in endocytosis of epidermal growth factor. We conclude that MADD deficiency underlies multiple cellular defects that can be attributed to alterations of TNF-α-dependent signalling pathways and defects in vesicular trafficking. Our data highlight the multifaceted role of MADD as a signalling molecule in different organs and reveal its physiological role in regulating the function of the sensory and autonomic nervous system and endo- and exocrine glands.

EIF2AK1 and EIF2AK2 encode members of the eukaryotic translation initiation factor 2 alpha kinase (EIF2AK) family that inhibits protein synthesis in response to physiologic stress conditions. EIF2AK2 is also involved in innate immune response and the regulation of signal transduction, apoptosis, cell proliferation, and differentiation. Despite these findings, human disorders associated with deleterious variants in EIF2AK1 and EIF2AK2 have not been reported. Here, we describe the identification of nine unrelated individuals with heterozygous de novo missense variants in EIF2AK1 (1/9) or EIF2AK2 (8/9). Features seen in these nine individuals include white matter alterations (9/9), developmental delay (9/9), impaired language (9/9), cognitive impairment (8/9), ataxia (6/9), dysarthria in probands with verbal ability (6/9), hypotonia (7/9), hypertonia (6/9), and involuntary movements (3/9). Individuals with EIF2AK2 variants also exhibit neurological regression in the setting of febrile illness or infection. We use mammalian cell lines and proband-derived fibroblasts to further confirm the pathogenicity of variants in these genes and found reduced kinase activity. EIF2AKs phosphorylate eukaryotic translation initiation factor 2 subunit 1 (EIF2S1, also known as EIF2α), which then inhibits EIF2B activity. Deleterious variants in genes encoding EIF2B proteins cause childhood ataxia with central nervous system hypomyelination/vanishing white matter (CACH/VWM), a leukodystrophy characterized by neurologic regression in the setting of febrile illness and other stressors. Our findings indicate that EIF2AK2 missense variants cause a neurodevelopmental syndrome that may share phenotypic and pathogenic mechanisms with CACH/VWM.

BackgroundVariants in HECW2 have recently been reported to cause a neurodevelopmental disorder with hypotonia, seizures and impaired language; however, only six variants have been reported and the clinical characteristics have only broadly been defined.MethodsMolecular and clinical data were collected from clinical and research cohorts. Massive parallel sequencing was performed and identified individuals with a HECW2-related neurodevelopmental disorder.ResultsWe identified 13 novel missense variants in HECW2 in 22 unpublished cases, of which 18 were confirmed to have a de novo variant. In addition, we reviewed the genotypes and phenotypes of previously reported and new cases with HECW2 variants (n=35 cases). All variants identified are missense, and the majority of likely pathogenic and pathogenic variants are located in or near the C-terminal HECT domain (88.2%). We identified several clustered variants and four recurrent variants (p.(Arg1191Gln);p.(Asn1199Lys);p.(Phe1327Ser);p.(Arg1330Trp)). Two variants, (p.(Arg1191Gln);p.(Arg1330Trp)), accounted for 22.9% and 20% of cases, respectively. Clinical characterisation suggests complete penetrance for hypotonia with or without spasticity (100%), developmental delay/intellectual disability (100%) and developmental language disorder (100%). Other common features are behavioural problems (88.9%), vision problems (83.9%), motor coordination/movement (75%) and gastrointestinal issues (70%). Seizures were present in 61.3% of individuals. Genotype-phenotype analysis shows that HECT domain variants are more frequently associated with cortical visual impairment and gastrointestinal issues. Seizures were only observed in individuals with variants in or near the HECT domain.ConclusionWe provide a comprehensive review and expansion of the genotypic and phenotypic spectrum of HECW2 disorders, aiding future molecular and clinical diagnosis and management.

1. Maura R.Z. Ruzhnikov, MD*,† 2. Elise Brimble, MS, MSc* 3. Rachel E. Hickey, MS‡ 4. on behalf of the Leukodystrophy Care Network 1. *Department of Neurology and Neurological Sciences and 2. †Division of Medical Genetics, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA. 3. ‡Department of Medical Genetics, Ann & Robert H. Lurie Children's Hospital, Chicago, IL. * Abbreviations: CNS: : central nervous system HSCT: : hematopoietic stem cell transplant MLD: : metachromatic leukodystrophy MRI: : magnetic resonance imaging PMD: : Pelizaeus-Merzbacher disease X-ALD: : X-linked adrenoleukodystrophy 1. Clinicians should be familiar with leukodystrophies as a distinct disease group and with symptoms suggestive of a leukodystrophy requiring prompt evaluation and referral. 2. Clinicians should recognize the urgency of diagnosis for leukodystrophies that have time-sensitive therapies. 3. Clinicians should be knowledgeable about the initial evaluation, recommended referrals, and resources for patients and families with a suspected leukodystrophy. After completing this article, readers should be able to: 1. Recognize symptoms of the more common leukodystrophies, including X-linked adrenoleukodystrophy, metachromatic leukodystrophy, Krabbe disease, and Pelizaeus-Merzbacher disease. 2. Describe the importance and limitations of brain magnetic resonance imaging for recognition and diagnosis of a leukodystrophy. 3. Be aware of the commonly used biochemical and genetic tests when considering a leukodystrophy diagnosis. 4. Formulate a plan for prompt evaluation and referral to appropriate specialists for children with a suspected leukodystrophy. 5. Support families with a diagnosis of a leukodystrophy by providing disease-specific resources. Leukodystrophies are inherited white matter disorders of the central nervous system (CNS) that are often characterized by progressive neurologic decline and early mortality. Early presenting features can be nonspecific and masquerade as common pediatric complaints, including inattention, irritability, or motor delays before progressing to frank developmental regression or neurodegeneration. Without familiarity with these disorders, their early manifestations may seem unrelated before the subsequent decline. The insidious nature of these disorders often leads to a prolonged …

Pathogenic variants in SETD1B have been associated with a syndromic neurodevelopmental disorder including intellectual disability, language delay and seizures. To date, clinical features have been described for eleven patients with (likely) pathogenic SETD1B sequence variants. We perform an in-depth clinical characterization of a cohort of 36 unpublished individuals with SETD1B sequence variants, describing their molecular and phenotypic spectrum. Selected variants were functionally tested using in vitro and genome-wide methylation assays. Our data present evidence for a loss-of-function mechanism of SETD1B variants, resulting in a core clinical phenotype of global developmental delay, language delay including regression, intellectual disability, autism and other behavioral issues, and variable epilepsy phenotypes. Developmental delay appeared to precede seizure onset, suggesting SETD1B dysfunction impacts physiological neurodevelopment even in the absence of epileptic activity. Interestingly, males are significantly overrepresented and more severely affected, and we speculate that sex-linked traits could affect susceptibility to penetrance and the clinical spectrum of SETD1B variants. Finally, despite the possibility of non-redundant contributions of SETD1B and its paralogue SETD1A to epigenetic control, the clinical phenotypes of the related disorders share many similarities, indicating that elucidating shared and divergent downstream targets of both genes will help to understand the mechanism leading to the neurobehavioral phenotypes. Insights from this extensive cohort will facilitate the counseling regarding the molecular and phenotypic landscape of newly diagnosed patients with the SETD1B-related syndrome.

Metabolic disorders represent rare but often treatable causes of seizures and epilepsy of neonatal onset. As seizures are relatively common in the neonatal period, systemic clues to a specific diagnosis may be lacking or shrouded by acute illness. An important role of the consulting pediatric neurologist is to identify neonates with a possible metabolic or otherwise genetic diagnosis. In this review, the authors describe presenting signs and symptoms, a diagnostic framework, and disorder-specific treatment options for inborn errors of metabolism that may present in the neonatal period. Specific attention is given to the neurologic aspects of each condition, including the electroclinical phenotype and findings on brain imaging. As expedited diagnosis and prompt initiation of available therapies have been demonstrated to result in improved epilepsy and developmental outcomes, this work acts as a framework to guide evaluation when an inherited metabolic disorder is suspected. In addition to informing treatment, a definitive diagnosis allows for appropriate counseling regarding prognosis, any associated screening or preventive measures, and family planning.

EIF2AK1andEIF2AK2encode members of the Eukaryotic Translation Initiation Factor 2 Alpha Kinase (EIF2AK) family that inhibits protein synthesis in response to physiologic stress conditions. EIF2AK2 is also involved in innate immune response and the regulation of signal transduction, apoptosis, cell proliferation, and differentiation. Despite these findings, human disorders associated with deleterious variants inEIF2AK1andEIF2AK2have not been reported. Here, we describe the identification of eight unrelated individuals with heterozygousde novomissense variants inEIF2AK1(1/8) orEIF2AK2(7/8). Features seen in these eight individuals include white matter alterations (8/8), developmental delay (8/8), impaired language (8/8), cognitive impairment (7/8), ataxia (6/8), dysarthria in probands with verbal ability (6/6), hypotonia (6/8), hypertonia (5/8), and involuntary movements (3/8). Individuals withEIF2AK2variants also exhibit neurological regression in the setting of febrile illness or infection. We use mammalian cell lines and patient-derived fibroblasts to further confirm the pathogenicity of variants in these genes and found reduced kinase activity. EIF2AKs phosphorylate Eukaryotic Translation Initiation Factor 2 Subunit 1, (EIF2S1, also known as EIF2α), which then inhibits EIF2B activity. Deleterious variants in genes encoding EIF2B proteins cause childhood ataxia with central nervous system hypomyelination/vanishing white matter disease (CACH/VWM), a leukoencephalopathy characterized by neurologic regression in the setting of febrile illness and other stressors. Our findings indicate thatEIF2AK2missense variants cause a neurodevelopmental syndrome that may share phenotypic and pathogenic mechanisms with CACH/VWM.

Triosephosphate isomerase (TPI) deficiency (Df) is a rare recessive metabolic disorder that manifests as hemolytic anemia, locomotor impairment, and progressive neurodegeneration. Research suggests that TPI Df mutations, including the “common” TPIE105D mutation, result in reduced TPI protein stability that appears to underlie disease pathogenesis. Drosophila with the recessive TPIsugarkill allele (a.k.a. sgk or M81T) exhibit progressive locomotor impairment, neuromuscular impairment and reduced longevity, modeling the human disorder. TPIsugarkill produces a functional protein that is degraded by the proteasome. Molecular chaperones, such as Hsp70 and Hsp90, have been shown to contribute to the regulation of TPIsugarkill degradation. In addition, stabilizing the mutant protein through chaperone modulation results in improved TPI deficiency phenotypes. To identify additional regulators of TPIsugarkill degradation, we performed a genome-wide RNAi screen that targeted known and predicted quality control proteins in the cell to identify novel factors that modulate TPIsugarkill turnover. Of the 430 proteins screened, 25 regulators of TPIsugarkill were identified. Interestingly, 10 proteins identified were novel, previously undescribed Drosophila proteins. Proteins involved in co-translational protein quality control and ribosome function were also isolated in the screen, suggesting that TPIsugarkill may undergo co-translational selection for polyubiquitination and proteasomal degradation as a nascent polypeptide. The proteins identified in this study may reveal novel pathways for the degradation of a functional, cytosolic protein by the ubiquitin proteasome system and define therapeutic pathways for TPI Df and other biomedically important diseases.

Type 2A protein phosphatases (PP2As) are highly expressed in the brain and regulate neuronal signaling by catalyzing phospho-Ser/Thr dephosphorylations in diverse substrates. PP2A holoenzymes comprise catalytic C-, scaffolding A-, and regulatory B-type subunits, which determine substrate specificity and physiological function. Interestingly, de novo mutations in genes encoding A- and B-type subunits have recently been implicated in intellectual disability (ID) and developmental delay (DD). We now report 16 individuals with mild to profound ID and DD and a de novo mutation in PPP2CA, encoding the catalytic Cα subunit. Other frequently observed features were severe language delay (71%), hypotonia (69%), epilepsy (63%), and brain abnormalities such as ventriculomegaly and a small corpus callosum (67%). Behavioral problems, including autism spectrum disorders, were reported in 47% of individuals, and three individuals had a congenital heart defect. PPP2CA de novo mutations included a partial gene deletion, a frameshift, three nonsense mutations, a single amino acid duplication, a recurrent mutation, and eight non-recurrent missense mutations. Functional studies showed complete PP2A dysfunction in four individuals with seemingly milder ID, hinting at haploinsufficiency. Ten other individuals showed mutation-specific biochemical distortions, including poor expression, altered binding to the A subunit and specific B-type subunits, and impaired phosphatase activity and C-terminal methylation. Four were suspected to have a dominant-negative mechanism, which correlated with severe ID. Two missense variants affecting the same residue largely behaved as wild-type in our functional assays. Overall, we found that pathogenic PPP2CA variants impair PP2A-B56(δ) functionality, suggesting that PP2A-related neurodevelopmental disorders constitute functionally converging ID syndromes. ispartof: American Journal Of Human Genetics vol:104 issue:1 pages:139-156 ispartof: location:United States status: published

Background: Infantile spasms (IS) is a neurologic disorder of childhood where time to treatment may affect long-term outcomes. Due to the clinical complexity of IS, care can be delayed. Objective: To determine if the use of electronic medical record templates (EMRTs) improved care quality in patients treated for IS. Method: Records of patients newly diagnosed with IS were retrospectively reviewed both before and after creation of an EMRT for the workup and treatment of IS. Quality of care measures reviewed included delays in treatment plan, medication administration, obtaining neurodiagnostic studies and discharge. The need for repeat neurodiagnostic studies was also assessed. Resident physicians were surveyed regarding template ease of use and functionality. Results: Of 17 patients with IS, 7 received template-based care and 10 did not. Patients in the non-template group had more delays in treatment ( p = 0.010), delay in medication administration ( p = 0.10), delay in diagnostic studies ( p = 0.01) and delay in discharge ( p = 0.39). Neurodiagnostic studies needed to be repeated in 5 out of 10 patients in the non-template group and none of the 7 patients in the template group ( p = 0.04). Surveyed resident physicians reported improved coordination in care, avoidance of delays in discharge and improved ability to predict side effects of treatment with template use. Conclusion: In a single centre, the use of protocolised EMRTs decreased treatment delays and the need for repeated invasive procedures in patients with newly diagnosed IS and was reported as easy to use by resident physicians. Implications: The use of protocolised EMRTs may improve the quality of patient care in IS and other rare diseases.

Infantile spasms of unknown cause: predictors of outcome and genotype-phenotype correlation Yuskaitis CJ, Ruzhnikov MRZ, Howell KB, et al. Pediatr Neurol. 2018;87:48-56. doi:10.1016/j.pediatrneurol.2018.04.012. Epub 2018 May 7.No large-scale studies have specifically evaluated the outcomes of infantile spasms (IS) of unknown cause, previously known as cryptogenic or idiopathic. The Epilepsy Phenome/Genome Project (EPGP) aimed to characterize IS of unknown cause by phenotype and genotype analysis.We undertook a retrospective multicenter observational cohort of 133 individuals within the EPGP database met criteria for IS of unknown cause with at least 6 months of follow-up data. Clinical medical records, imaging, and electroencephalography were examined.Normal development occurred in only 15% of IS of unknown cause. The majority (85%) had clinically documented developmental delay (15% mild, 20% moderate, and 50% severe) at last assessment (median 2.7 years; interquartile interval 1.71-6.25 years). Predictors of positive developmental outcomes included no delay prior to IS ( P.001), older age of IS onset (median 6 months old), and resolution of IS after initial treatment ( P.001). Additional seizures after IS occurred in 67%, with predictors being seizures prior to IS ( P = .018), earlier age of IS onset (median 5 months old), and refractory IS ( P = .008). On a research basis, whole exome sequencing identified 15% with de novo variants in known epilepsy genes. Individuals with a genetic finding were more likely to have poor developmental outcomes ( P = .035).The current study highlights the predominately unfavorable developmental outcomes and that subsequent seizures are common in children with IS of unknown cause. Ongoing genetic evaluation of IS of seemingly unknown cause is likely to yield a diagnosis and provide valuable prognostic information.