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Bohring-Opitz syndrome (BOS) is a rare disease with a characteristic facial appearance and limb position. This report describes a case of BOS complicated by persistent pulmonary hypertension of the newborn (PPHN) and formation of abnormal alveoli that was confirmed by autopsy. A female neonate was born by cesarean section at 37 weeks and 2 days of gestation and found to have a nevus flammeus, exophthalmos, abnormal palate, retraction of the mandible, and a posture characteristic of BOS. The patients had severe PPHN requiring inhalation of nitric oxide. Genetic testing revealed a de novo frameshift variant in ASXL1. Autopsy revealed that the lung was at the saccular stage, equivalent to 28-34 weeks of gestation. This is the first report to present pathological evidence of immaturity of the lung that may be associated with PPHN in a patient with BOS caused by a variant in ASXL1., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interests., (Copyright © 2024. Published by Elsevier Masson SAS.)

Digital clubbing is characterized by bulbous enlargement of the terminal segments of the fingers. Hypotheses including hypoxia have been proposed for the pathogenesis of digital clubbing, but the exact pathogenesis of digital clubbing is still uncertain. Lysinuric protein intolerance (LPI) is caused by pathogenic variants in SLC7A7 and is often associated with interstitial lung disease. Previously two patients of LPI with digital clubbing but without hypoxia have been reported. It is unclear whether digital clubbing in LPI is secondary to hypoxia or directly related to SLC7A7 deficiency. Here we report a 6-year-old Japanese boy presented with digital clubbing without hypoxia. He had episodic vomiting, each episode consisting of a single vomiting event occurring once a month, and his growth had been delayed. He had interstitial lung disease and hepatomegaly. He had compound heterozygous pathogenic variants in the SLC7A7, leading to the diagnosis of LPI. Together with the two previously reported patients mentioned above, we conclude that digital clubbing can occur in the absence of hypoxia. Digital clubbing in the absence of hypoxia has been observed in two genetic disorders related to prostaglandin (PG) E2, HPGD and SLCO2A1. PGE2 synthesis is primarily regulated by the cyclooxygenase 2, which plays a critical role in the control of inflammation. A high urine PGE level in the patient was compatible with the notion that PGE2 production may be increased in LPI. The occurrence of digital clubbing in the absence of hypoxia in LPI patients with SLC7A7 may be attributed to the mechanism of increased PGE2 production., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

CCP110 (centriolar coiled coil protein 110, also known as CP110) is one of the essential proteins localized in the centrosome that plays critical roles in the regulation of the cell cycle and also in the initiation of ciliogenesis. So far, no human congenital disorders have been identified to be associated with pathogenic variants of CCP110. Mice with biallelic loss-of-function variants of Ccp110 (Ccp110 -/- ) are known to manifest multiple organ defects, including a small body size, polydactyly, omphalocele, congenital heart defects, cleft palate, short ribs, and a small thoracic cage, a pattern of abnormalities closely resembling that in "ciliopathies" in humans. Herein, we report a 7-month-old male infant who presented with growth failure and skeletal abnormalities, including a narrow thorax and severe brachydactyly. Trio exome analysis of the genomic DNA of the patient and his parents showed that the patient was a compound heterozygote for truncating variants of CCP110, including a frameshift variant NM_001323572.2:c.856_857del, p.(Val286Leufs*5) inherited from the father, and a nonsense variant NM_001323572.2:c.1129C>T, p.(Arg377*) inherited from the mother. The strikingly similar pattern of malformations between Ccp110 -/- mice and the 7-month-old male infant reported herein carrying unequivocal truncating CCP110 variants strongly supports the contention that CCP110 is a novel disease-causative gene., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

DExH-box helicases are involved in unwinding of RNA and DNA. Among the 16 DExH-box genes, monoallelic variants of DHX16, DHX30, DHX34, and DHX37 are known to be associated with neurodevelopmental disorders. In particular, DHX30 is well established as a causative gene for neurodevelopmental disorders. Germline variants of DHX9, the closest homolog of DHX30, have not been reported until now as being associated with congenital disorders in humans, except that one de novo heterozygous variant, p.(Arg1052Gln) of the gene was identified during comprehensive screening in a patient with autism; unfortunately, the phenotypic details of this individual are unknown. Herein, we report a patients with a heterozygous de novo missense variant, p.(Gly414Arg) of DHX9 who presented with a short stature, intellectual disability, and ventricular non-compaction cardiomyopathy. The variant was located in the glycine codon of the ATP-binding site, G-C-G-K-T. To assess the pathogenicity of these variants, we generated transgenic Drosophila lines expressing human wild-type and mutant DHX9 proteins: 1) the mutant proteins showed aberrant localization both in the nucleus and the cytoplasm; 2) ectopic expression of wild-type protein in the visual system led to the rough eye phenotype, whereas expression of the mutant proteins had minimal effect; 3) overexpression of the wild-type protein in the retina led to a reduction in axonal numbers, whereas expression of the mutant proteins had a less pronounced effect. Furthermore, in a gene-editing experiment of Dhx9 G416 to R416, corresponding to p.(Gly414Arg) in humans, heterozygous mice showed a reduced body size, reduced emotionality, and cardiac conduction abnormality. In conclusion, we established that heterozygosity for a loss-of-function variant of DHX9 can lead to a new neurodevelopmental disorder., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to disclose., (Copyright © 2023. Published by Elsevier Masson SAS.)

The CpG island flanking the promoter region of SNRPN on chromosome 15q11.2 contains CpG sites that are completely methylated in the maternally derived allele and unmethylated in the paternally derived allele. Both unmethylated and methylated alleles are observed in normal individuals. Only the methylated allele is observed in patients with Prader-Willi syndrome, whereas only the unmethylated allele is observed in those with Angelman syndrome. Hence, detection of aberrant methylation at the differentially methylated region is fundamental to the molecular diagnosis of Prader-Willi syndrome and Angelman syndromes. Traditionally, bisulfite treatment and methylation-sensitive restriction enzyme treatment or methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) have been used. We here developed a long-read sequencing assay that can distinguish methylated and unmethylated CpG sites at 15q11.2 by the difference in current intensity generated from nanopore reads. We successfully diagnosed 4 Prader-Willi syndrome patients and 3 Angelman syndrome patients by targeting differentially methylated regions. Concurrent copy number analysis, homozygosity analysis, and structural variant analysis also allowed us to precisely delineate the underlying pathogenic mechanisms, including gross deletion, uniparental heterodisomy, uniparental isodisomy, or imprinting defect. Furthermore, we showed allele-specific methylation in imprinting-related differentially methylated regions on chromosomes 6, 7, 11, 14, and 20 in a normal individual together with 4 Prader-Willi patients and 3 Angelman syndrome patients. Hence, presently reported method is likely to be applicable to the diagnosis of imprinting disorders other than Prader-Willi syndrome and Angelman syndrome as well., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to disclose., (Copyright © 2022. Published by Elsevier Masson SAS.)

Oral-facial digital (OFD) syndrome is characterized by abnormalities of the face (hypertelorism and low set-ears), oral cavity (multiple frenula, lingual hamartoma, or lobulated tongue) and extremities (postaxial polydactyly). At least 19 genes have been implicated in the development of OFD syndrome. Herein, we report the case a 13-year-old patient with atrioventricular septal defect, moderate intellectual disability, epilepsy, and features of OFD, including multiple oral frenula, and postaxial polydactyly of the hands and feet. The patient had a de novo heterozygous variant in PRKACB: chr1(GRCh37):g.84700915T > C, c.1124T > C (NM_182948.4), p.(Phe375Ser). To date, four patients with pathogenic monoallelic variants in PRKACB have been reported, and the condition associated with these variants is referred to as Cardioacrofacial dysplasia-2 (CAFD2, MIM619143). Previously reported features of this condition include congenital heart disease (e.g., atrioventricular septal defect) and postaxial polydactyly, and two of the patients had multiple oral frenula. We suggest that a significant phenotypic overlap exists between CAFD2 and OFD syndrome, in that these patients especially share the features of postaxial polydactyly and multiple oral frenula. The phenotypic similarity between patients with CAFD2 and classic OFD syndrome with an OFD1 variant might be explained by the recent in vitro experimental finding that a protein kinase A subunit encoded by PRKACB directly phosphorylates the OFD1 protein. From the standpoint of genetic counseling, OFD syndrome type1, the prototypic form of OFD, exhibits an X-linked dominant inheritance pattern, whereas other forms of OFD syndrome exhibit an autosomal recessive inheritance pattern. Recognition of CAFD2 as a differential diagnosis or forme fruste of OFD syndrome suggests that an autosomal dominant pattern of inheritance should also be considered during genetic counseling., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

Neurocutaneous disorders are caused by germline and/or somatic mutations and involve the integument and central nervous systems. Congenital melanocytic nevus syndrome is characterized by melanotic skin lesions caused by somatic mutations at codon 61 in NRAS. A large cutaneous lesion raises the risk of central nervous system involvement. We report an 8-year-old girl with a congenital giant pigmented nevus that covered almost her entire back. Despite the absence of any radiological evidence of intracranial melanosis, the patient exhibited progressive limb spasticity with preserved intellectual ability. An extensive genetic analysis identified a specific class of heterozygous germline mutation in SPAST, p.(Arg499His), which is responsible for hereditary spastic paraplegia with infantile onset. In addition, a known heterozygous somatic mutation in NRAS, p.(Gln61Lys) was detected in the cutaneous lesion. This observation recapitulates concomitant mosaicism and non-mosaicism within a single individual and suggests that the possibility of a dual genetic diagnosis should be considered when neurological decline is observed in a patient with a neurocutaneous disorder without any detectable intracranial lesions., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Among the many regulators of microRNA formation, Argonaute 1 (AGO1) plays critical roles in RNA interference, which controls a wide range of biological activities. Recent large-scale genomic studies have identified at least five patients with intellectual disability/autism spectrum disorder who had de novo mutations in AGO1, but detailed clinical information was not available. The recognizable clinical features that are associated with AGO1 mutations remain to be determined. The proposita was a 15-year-old girl with diffuse hypotonia, infrequent seizures, and intellectual disability with an intelligence quotient of 41. She had characteristic facial features consisting of telecanthus, wide nasal bridge with bulbous nasal tip, and a round face with downslanted palpebral fissures. Serial computed tomography scans showed progressive calcification in the globus pallidus that became evident during childhood. A whole exome analysis in trio revealed a de novo heterozygous mutation in AGO1, i.e., c.595G > A p.(Gly199Ser). The distinctive facial features, i.e., telecanthus, wide nasal bridge with bulbous nasal tip, and a round face with downslanted palpebral fissures, closely resembled previously reported patients who had a chromosomal microdeletion encompassing AGO1 locus. The combinatory phenotype of such characteristic facial features and radiographic features, i.e. progressive calcification in the globus pallidus, in the presently reported patient suggest that AGO1 mutations lead to a syndromic form of intellectual disability/autism spectrum disorder. Distinctive facial features with early and progressive calcification in the globus pallidus may be suggestive of the presence of AGO1 mutations., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Loss-of-function mutations in coagulation cascade proteins lead to bleeding diasthesis. In contrast, gain-of-function mutations in these proteins, which are exceptionally rare, lead to hereditary thrombosis. This is best exemplified by Factor V (i.e., Factor V Leiden) and Factor II (i.e., p.Arg596Leu). Here, we report a family with hereditary thrombosis. The proposita presented with cerebral venous thrombosis accompanied by infarction at the age of 12 years. Despite anticoagulation therapy with oral warfarin, she later developed deep venous thrombosis in her hepatic portal veins at the age of 27 years. A medical exome analysis identified a de novo heterozygous mutation p.Tyr434His in Factor II, which was segregated within the family. A retrospective molecular diagnosis was made using a preserved surgical specimen from the proposita's mother, who had died 10 years earlier. The p.Tyr434 residue, which was substituted in the presently reported family, was located in "exosite I" of thrombin, a critical recognition site for fibrinogen, protein C, and thrombin aptamer. Therefore, the mutant thrombin likely exerted its thrombophilic effect by altering the affinity of thrombin to downstream substrates. Furthermore, the "exosite I" domain of thrombin was inhibited by the arthropod bleeding toxin Triabin (a protein discovered from the saliva of the blood-sucking triatomine bug Triatoma pallidipennis). Our observation that patients with a p.Tyr434His mutation exhibited recurrent thrombosis provides the first proof-of-concept in humans that a pharmacologic agent targeting "exosite I" could be an effective means of specifically modulating the thrombogenic-side of the coagulation system via the inhibition of factor II., (Copyright © 2018. Published by Elsevier Masson SAS.)

Recently, 7 patients with de novo constitutional non-synonymous mutations in the CDK13 gene were ascertained through a trio exome analysis of a large cohort of 610 patients with congenital cardiac diseases. Despite another report describing 9 additional patients, the clinical spectrum of this condition has yet to be defined. Herein, we report 3 patients with heterozygous constitutional CDK13 mutations, who were ascertained through exome analysis of children with intellectual disability and minor anomalies, who lacked cardiac anomalies. Two patients had a c.2149G > A, p.Gly717Arg mutation, and one had a c.2525A > G, p. Asn842Ser mutation. A review of the previously described patients and those described herein has enabled the following points to be clarified. First, congenital heart diseases are not an essential feature (13/19). Second, nasal features may help syndromic recognition (14/16). Third, widely spaced and peg-shaped teeth may represent a previously unappreciated diagnostic clue for this newly identified syndrome. Here, we show that p.Gly717Arg represents a hotspot in addition to p.Asn842Ser. We suggest that this CDK13-related disorder may represent a clinically recognizable syndrome., (Copyright © 2017. Published by Elsevier Masson SAS.)

Cleidocranial dysplasia is a skeletal disorder characterized by a defective skull and defective clavicles caused by RUNX2, an activator of osteoblast differentiation. Consistent with the expression pattern of RUNX2, this disorder typically affects the skeletal system, but not the central nervous system. A 56-year-old man with the prototypic skeletal defects of cleidocranial dysplasia and a RUNX2 deletion presented with a progressive cognitive decline after the age of 40 years. After a failed cranioplasty during childhood, he had worn a protective helmet until young adulthood. His current neuroimaging studies revealed extensive cystic encephalomalacia beneath the defective skull, suggesting that his cognitive decline could likely be attributed to repetitive cerebral contusions. Late-onset progressive cognitive decline in the context of a defective skull accompanied by extensive cystic encephalomalacia illustrates the importance of natural calvarial protection against head injury. Since the majority of patients with cleidocranial dysplasia do not wear protective helmets beyond childhood, mainly for cosmetic reasons, a discussion of whether the social disadvantage outweighs the potential risk of brain parenchymal injury may be necessary., (Copyright © 2014. Published by Elsevier Masson SAS.)

The classification of bone dysplasia has relied on a clinical/radiographic interpretation and the identification of specific genetic alterations. The clinical presentation of the SOX9 mutation and type 2 collagen disorders overlap with the Pierre-Robin sequence and talipes equinovarus, but the former is often accompanied by the bent long bones. In its milder form, the SOX9 mutation is not necessarily associated with the bent long bones. Here, we report a patient with the Pierre-Robin sequence and talipes equinovarus who did not exhibit either bent long bones or scapular hypoplasia; thus, this patient was instead classified as having a type 2 collagen disorder. Despite this phenotypic presentation, the proposita was found to have a de novo SOX9 mutation. The peculiar location of the mutation within the dimerization domain might account for the relatively mild phenotypic effect of the SOX9 mutation to a degree that is compatible with a clinical diagnosis of type 2 collagen disorder, except for a developmental delay. We concluded that mutations in SOX9 can mimic a type 2 collagen disorder-like phenotype., (Copyright © 2014. Published by Elsevier Masson SAS.)

BMP4 and OTX2 are master genes in ophthalmogenesis. Mutations of BMP4 and OTX2 often lead to eye defects, including anophthalmia-microphthalmia. A significant degree of variable expressivity has been reported in heterozygous individuals with BMP4 or OTX2 mutation. Interestingly, both BMP4 and OTX2 reside on 14q22, being only 2.8 Mb apart. Previous studies reported that among three patients with 14q22 deletion involving BMP4 and OTX2, all had severe eye defects. The minimal degree of variable expressivity among these individuals who were doubly deleted for BMP4 and OTX2 could be attributed to the combinatorial relationship of the two genes observed in animal models. We herein report a patient with a concurrent deletion of BMP4 and OTX2 who exhibited bilateral microphthalmia, more specifically, anterior segment dysgenesis with microcornea. Evolutionarily conserved physical linkage of Bmp4 and Otx2 loci may suggest an advantage of the proximal alignment of the two genes. Another striking feature in the propositus was the progressive white matter loss observed by serial neuroimaging. A review of twelve previously reported patients with 14q22 microdeletion revealed decreased white matter volume in half of the patients. It remains to be elucidated whether the white matter lesion is age-dependent and progressive. In conclusion, anterior segment defects of the eyes, especially when accompanied by decreased white matter volume on neuroimaging, should raise the clinical suspicion of 14q22 microdeletion., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)