Porencephaly in a fetus and HANAC in her father: variable expression of COL4A1 mutation.

COL4A1-associated disorders encompass a wide range of hereditary vasculopathy, including porencephaly and HANAC (adult-onset hemorrhagic stroke with cerebral aneurysm and retinal arterial tortuosity, renal cysts, and thenar muscle cramp). It remains elusive whether or not porencephaly and HANAC are molecularly distinctive disorders due to different classes of mutations. We report on a girl with porencephaly and an episode of microangiopathic hemolysis in infancy and her father with HANAC, both of whom had a heterozygous missense mutation of COL4A1 (c.3715G>A, p.G1239R). The current observation implies phenotypic diversities of COL4A1 mutations.

The use of next-generation sequencing in molecular diagnosis of neurofibromatosis type 1: a validation study.

AIMS: We assessed the validity of a next-generation sequencing protocol using in-solution hybridization-based enrichment to identify NF1 mutations for the diagnosis of 86 patients with a prototypic genetic syndrome, neurofibromatosis type 1. In addition, other causative genes for classic genetic syndromes were set as the target genes for coverage analysis. RESULTS: The protocol identified 30 nonsense, 19 frameshift, and 8 splice-site mutations, together with 10 nucleotide substitutions that were previously reported to be pathogenic. In the remaining 19 samples, 10 had single-exon or multiple-exon deletions detected by a multiplex ligation-dependent probe amplification method and 3 had missense mutations that were not observed in the normal Japanese SNP database and were predicted to be pathogenic. Coverage analysis of the genes other than the NF1 gene included on the same diagnostic panel indicated that the mean coverage was 115-fold, a sufficient depth for mutation detection. CONCLUSIONS: The overall mutation detection rate using the currently reported method in 86 patients who met the clinical diagnostic criteria was 92.1% (70/76) when 10 patients with large deletions were excluded. The results validate the clinical utility of this next-generation sequencing-based method for the diagnosis of neurofibromatosis type 1. Comparable detection rates can be expected for other genetic syndromes, based on the results of the coverage analysis.

Severe craniosynostosis with Noonan syndrome phenotype associated with SHOC2 mutation: clinical evidence of crosslink between FGFR and RAS signaling pathways.

Dysregulation in the RAS signaling cascade results in a family of malformation syndromes called RASopathies. Meanwhile, alterations in FGFR signaling cascade are responsible for various syndromic forms of craniosynostosis. In general, the phenotypic spectra of RASopathies and craniosynostosis syndromes do not overlap. Recently, however, mutations in ERF, a downstream molecule of the RAS signaling cascade, have been identified as a cause of complex craniosynostosis, suggesting that the RAS and FGFR signaling pathways can interact in the pathogenesis of malformation syndromes. Here, we document a boy with short stature, developmental delay, and severe craniosynostosis involving right coronal, bilateral lambdoid, and sagittal sutures with a de novo mutation in exon1 of SHOC2 (c.4A>G p.Ser2Gly). This observation further supports the existence of a crosslink between the RAS signaling cascade and craniosynostosis. In retrospect, the propositus had physical features suggestive of a dysregulated RAS signaling cascade, such as fetal pleural effusion, fetal hydrops, and atrial tachycardia. In addition to an abnormal cranial shape, which has been reported for this specific mutation, craniosynostosis might be a novel associated phenotype. In conclusion, the phenotypic combination of severe craniosynostosis and RASopathy features observed in the propositus suggests an interaction between the RAS and FGFR signaling cascades. Patients with craniosynostosis in combination with any RASopathy feature may require mutation screening for molecules in the FGFR-RAS signaling cascade.

Clinical utility of an array comparative genomic hybridization analysis for Williams syndrome.

To reveal the relation between intellectual disability and the deleted intervals in Williams syndrome, we performed an array comparative genomic hybridization analysis and standardized developmental testing for 11 patients diagnosed as having Williams syndrome based on fluorescent in situ hybridization testing. One patient had a large 4.2-Mb deletion spanning distally beyond the common 1.5-Mb intervals observed in 10/11 patients. We formulated a linear equation describing the developmental age of the 10 patients with the common deletion; the developmental age of the patient with the 4.2-Mb deletion was significantly below the expectation (developmental age = 0.51 × chronological age). The large deletion may account for the severe intellectual disability; therefore, the use of array comparative genomic hybridization may provide practical information regarding individuals with Williams syndrome.

Progressive cognitive decline in an adult patient with cleidocranial dysplasia.

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.

SOX9 dimerization domain mutation mimicking type 2 collagen disorder phenotype.

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.

1p34.3 deletion involving GRIK3: Further clinical implication of GRIK family glutamate receptors in the pathogenesis of developmental delay.

A growing body of evidence suggests an association between microdeletion/microduplication and schizophrenia/intellectual disability. Abnormal neurogenesis and neurotransmission have been implicated in the pathogenesis of these neuropsychiatric and neurodevelopmental disorders. The kainate/AMPA-type ionotropic glutamate receptor (GRIK = glutamate receptor, ionotropic, kainate) plays a critical role in synaptic potentiation, which is an essential process for learning and memory. Among the five known GRIK family members, haploinsufficiency of GRIK1, GRIK2, and GRIK4 are known to cause developmental delay, whereas the roles of GRIK3 and GRIK5 remain unknown. Herein, we report on a girl who presented with a severe developmental delay predominantly affecting her language and fine motor skills. She had a 2.6-Mb microdeletion in 1p34.3 involving GRIK3, which encodes a principal subunit of the kainate-type ionotropic glutamate receptor. Given its strong expression pattern in the central nervous system and the biological function of GRIK3 in presynaptic neurotransmission, the haploinsufficiency of GRIK3 is likely to be responsible for the severe developmental delay in the proposita. A review of genetic alterations and the phenotypic effects of all the GRIK family members support this hypothesis. The current observation of a microdeletion involving GRIK3, a kainate-type ionotropic glutamate receptor subunit, and the neurodevelopmental manifestation in the absence of major dysmorphism provides further clinical implication of the possible role of GRIK family glutamate receptors in the pathogenesis of developmental delay.

Multiple café au lait spots in familial patients with MAP2K2 mutation.

Recent advances in genetic diagnostic technologies have made the classic disease nosology highly complicated. This situation is exemplified by rasopathies, among which neurofibromatosis type 1 and Noonan syndrome represent prototypic entities. The former condition is characterized by multiple café au lait spots and neurofibromas, while the latter is characterized by distinct facial features, webbed neck, congenital heart disease, and a short stature. On rare occasions, the features of both neurofibromatosis and Noonan syndrome co-exist within an individual; such patients are diagnosed as having neurofibromatosis-Noonan syndrome. Here, we report familial patients with multiple café au lait spots and Noonan syndrome-like facial features. A mutation analysis unexpectedly revealed a mutation in MAP2K2 in both the propositus and his mother. The propositus fulfilled the diagnostic criteria for neurofibromatosis type 1, but his mother did not. Their phenotype was not consistent with that of cardio-facio-cutaneous syndrome, which is classically known to be associated with MAP2K2 mutations. The mother of the propositus had cervical cancer at the age of 23 years, consistent with the oncogenic tendency associated with rasopathies. The phenotypic combination of multiple café au lait spots and Noonan syndrome-like facial features suggested a diagnosis of neurofibromatosis-Noonan syndrome. Whether this condition represents a discrete disease entity or a variable expression of neurofibromatosis type 1 has long been debated. The present observation suggests that some perturbation in the RAS/MAPK signaling cascade results in multiple café au lait spots, a key diagnostic phenotype of rasopathies, although the exact mechanism remains to be elucidated.

A novel mutation in SOX3 polyalanine tract: a case of Kabuki syndrome with combined pituitary hormone deficiency harboring double mutations in MLL2 and SOX3.

INTRODUCTION: Both duplications encompassing SOX3 and loss-of function mutations in SOX3 have been reported in a minor portion of X-linked isolated growth hormone deficiency (GHD) or combined pituitary hormone deficiency (CPHD) patients with or without mental retardation. PATIENTS AND METHODS: We report a Japanese male patient with molecularly confirmed Kabuki syndrome who was found to have CPHD. We analyzed all coding exons and flanking introns of currently known nine genes responsible for CPHD by PCR-based sequencing. RESULTS: In this CPHD patient, we identified a novel hemizygous 21-base pair deletion, resulting in the loss of 7 alanine residues from polyalanine (PA) tracts of SOX3. The clinically and endocrinologically normal mother of the patient carried the same deletion in a heterozygous manner. In vitro experiments showed that the del 7A SOX3 had increased transactivation of the HESX1 promoter. CONCLUSION: Our study provides additional evidence that deletion in PA tracts of SOX3 is associated with hypopituitarism. Female carriers of SOX3 PA tract deletions will show a broad phenotypic spectrum, ranging from clinically normal to CPHD.

Diverse spectrum of rare deafness genes underlies early-childhood hearing loss in Japanese patients: a cross-sectional, multi-center next-generation sequencing study.

BACKGROUND: Genetic tests for hereditary hearing loss inform clinical management of patients and can provide the first step in the development of therapeutics. However, comprehensive genetic tests for deafness genes by Sanger sequencing is extremely expensive and time-consuming. Next-generation sequencing (NGS) technology is advantageous for genetic diagnosis of heterogeneous diseases that involve numerous causative genes. METHODS: Genomic DNA samples from 58 subjects with hearing loss from 15 unrelated Japanese families were subjected to NGS to identify the genetic causes of hearing loss. Subjects did not have pathogenic GJB2 mutations (the gene most often associated with inherited hearing loss), mitochondrial m.1555A>G or 3243A>G mutations, enlarged vestibular aqueduct, or auditory neuropathy. Clinical features of subjects were obtained from medical records. Genomic DNA was subjected to a custom-designed SureSelect Target Enrichment System to capture coding exons and proximal flanking intronic sequences of 84 genes responsible for nonsyndromic or syndromic hearing loss, and DNA was sequenced by Illumina GAIIx (paired-end read). The sequences were mapped and quality-checked using the programs BWA, Novoalign, Picard, and GATK, and analyzed by Avadis NGS. RESULTS: Candidate genes were identified in 7 of the 15 families. These genes were ACTG1, DFNA5, POU4F3, SLC26A5, SIX1, MYO7A, CDH23, PCDH15, and USH2A, suggesting that a variety of genes underlie early-childhood hearing loss in Japanese patients. Mutations in Usher syndrome-related genes were detected in three families, including one double heterozygous mutation of CDH23 and PCDH15. CONCLUSION: Targeted NGS analysis revealed a diverse spectrum of rare deafness genes in Japanese subjects and underscores implications for efficient genetic testing.

Severe congenital lipodystrophy and a progeroid appearance: Mutation in the penultimate exon of FBN1 causing a recognizable phenotype.

Recently, three marfanoid patients with congenital lipodystrophy and a neonatal progeroid appearance were reported. Although their phenotype was distinct from that of classic Marfan syndrome, they all had a truncating mutation in the penultimate exon, i.e., exon 64, of FBN1, the causative gene for Marfan syndrome. These patients might represent a new entity, but the exact phenotypic and genotypic spectrum remains unknown. Here, we report on a girl born prematurely who exhibited severe congenital lipodystrophy and a neonatal progeroid appearance. The patient exhibited a characteristic growth pattern consisting of an accelerated growth in height with a discrepant poor weight gain. She had a characteristic facial appearance with craniosynostosis. A mutation analysis identified c.8175_8182del8bp, p.Arg2726Glufs*9 in exon 64 of the FBN1 gene. A review of similar, recently reported patients revealed that the cardinal features of these patients include (1) congenital lipodystrophy, (2) premature birth with an accelerated linear growth disproportionate to the weight gain, and (3) a progeroid appearance with distinct facial features. Lines of molecular evidence suggested that this new progeroid syndrome represents a neomorphic phenotype caused by truncated transcripts with an extremely charged protein motif that escapes from nonsense-mediated mRNA decay, altering FBN1-TGF beta signaling, rather than representing the severe end of the hypomorphic phenotype of the FBN1-TGF beta disorder spectrum. We propose that this marfanoid entity comprised of congenital lipodystrophy, a neonatal progeroid appearance, and a peculiar growth profile and caused by rare mutations in the penultimate exon of FBN1, be newly referred to as marfanoid-progeroid syndrome.

Severe obstructive sleep apnea in Loeys-Dietz syndrome successfully treated using continuous positive airway pressure.

Loeys-Dietz syndrome is a recently recognized connective tissue disorder characterized by severe craniofacial and skeletal abnormalities as well as arterial tortuosity with aggressive aneurysm formation. Marfan syndrome, a classic connective tissue disorder, is known to be associated with a risk of obstructive sleep apnea, but sleep-related breathing disorders have not been previously documented in Loeys-Dietz syndrome. The propositus had the prototypic features of Loeys-Dietz syndrome with a de novo mutation in TGFBR2. He developed severe obstructive sleep apnea during his infancy. Continuous positive airway pressure was introduced at age 7 years and provided significant improvement in his nocturnal apnea and sleep apnea-related symptoms, such as enuresis. Marfan syndrome is known to be associated with a high risk of sleep apnea because of its characteristic craniofacial and connective tissue abnormalities. Similarly, the severe craniofacial abnormalities in Loeys-Dietz syndrome may predispose patients to severe obstructive sleep apnea, even at a very young age. Despite the severity of obstructive sleep apnea in the propositus, the administration of continuous positive airway pressure was highly effective in alleviating his symptoms. In summary, severe obstructive sleep apnea was successfully treated using continuous positive airway pressure in a patient with Loeys-Dietz syndrome. Careful evaluation and aggressive intervention for the alleviation of obstructive sleep apnea is warranted in Loeys-Dietz syndrome.

Concurrent deletion of BMP4 and OTX2 genes, two master genes in ophthalmogenesis.

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.

Microduplication of Xq24 and Hartsfield syndrome with holoprosencephaly, ectrodactyly, and clefting.

The combination of holoprosencephaly and ectrodactyly, also known as Hartsfield syndrome, represents a unique genetic entity. An X-linked recessive mode of transmission has been suggested for this condition based on the observation that male patients have preferentially been affected. Thus far, no candidate genes have been suggested on the X chromosome. We report a male patient with a full-blown Hartsfield syndrome phenotype who had microduplication at Xq24 involving four genes. He presented with bilateral ectrodactyly of the hands (both hands had four fingers with a deep gap between the 2nd and 3rd digits), cleft lip and palate, and a depressed nasal bridge. Magnetic resonance imaging of the brain revealed lobar holoprosencephaly. His G-banded karyotype was normal. Array comparative genomic hybridization (CGH) using the Agilent 244K Whole Human Genome CGH array revealed a microduplication at Xq24 of 210 kb. Parental testing revealed that the deletion was derived from the asymptomatic mother. Of the genes on the duplicated interval, the duplications of SLC25A43 and SLC25A5 appeared to be the most likely to explain the patient's phenotype. From a clinical standpoint, it is important to point out that the propositus, who performs relatively well with holoprosencephaly and has a developmental quotient around 70, has survived multiple life-threatening episodes of hypernatremia. Awareness of the risk of hypernatremia is of great importance for the anticipatory management of patients with ectrodactyly and an oral cleft, even in the absence of overt hypotelorism.

12q14 microdeletion syndrome and short stature with or without relative macrocephaly.

Patients with 12q14 microdeletion can present with short stature with or without relative macrocephaly. When associated with relative macrocephaly, the phenotype resembles Silver-Russell syndrome (SRS). Short stature is attributable to haploinsufficiency of HMGA2, but a patient with a deletion at the HMGA2 locus only did not have macrocephaly. Hence, the presence of a separate locus for a relative macrocephaly phenotype was suggested. Herein, we present a girl with a 12q14 microdeletion involving the HMGA2 locus who had short stature but did not have macrocephaly. Inclusion and exclusion mappings based on a quantitative review of the degree of relative macrocephaly and the extent of the deletions in previously reported patients with a 12q14 microdeletion demonstrated a presumptive interval for relative macrocephaly spanning a few megabases. These results confirm that a deletion spanning both HMGA2 and this presumptive interval locus would cause an SRS-like phenotype.

Branchial arch defects and 19p13.12 microdeletion: defining the critical region into a 0.8 M base interval.

We present a patient with preauricular tags, preauricular and branchial pits, stenosis of the external auditory canals, mild hearing loss, and mild developmental delay who had a de novo 19p13.12 submicroscopic deletion. The size of the deletion was 760-kb, extending from 15,300,338 to 16,064,271 (hg18; NCBI Build 36.1). Our finding supports the notion that 19p13.12 represents a unique microdeletion syndrome characterized by branchial arch defects and the concept of exclusion mapping indicates that the putative locus for the branchial arch development is included in the 0.8-Mb interval defined by the deletion in the presently reported patient.