A de novo CTNNB1 nonsense mutation associated with syndromic atypical hyperekplexia, microcephaly and intellectual disability: a case report

From Feeding Challenges to Oral-Motor Dyspraxia: A Comprehensive Description of 10 New Cases with CTNNB1 Syndrome

CTNNB1 syndrome is an autosomal-dominant neurodevelopmental disorder featuring developmental delay; intellectual disability; behavioral disturbances; movement disorders; visual defects; and subtle facial features caused by de novo loss-of-function variants in the CTNNB1 gene. Due to paucity of data, this study intends to describe feeding issues and oral-motor dyspraxia in an unselected cohort of 10 patients with a confirmed molecular diagnosis. Pathogenic variants along with key information regarding oral-motor features were collected. Sialorrhea was quantified using the Drooling Quotient 5. Feeding abilities were screened using the Italian version of the Montreal Children's Hospital Feeding Scale (I-MCH-FS). Mild-to-severe coordination difficulties in single or in a sequence of movements involving the endo-oral and peri-oral muscles were noticed across the entire cohort. Mild-to-profuse drooling was a commonly complained-about issue by 30% of parents. The mean total I-MCH-FS t-score equivalent was 43.1 ± 7.5. These findings contribute to the understanding of the CTNNB1 syndrome highlighting the oral motor phenotype, and correlating specific gene variants with clinical characteristics.

CTNNB1-related neurodevelopmental disorder mimics cerebral palsy: case report

While somatic gain-of-function mutations in the CTNNB1 gene cause diverse malignancies, germline loss-of-function mutations cause neurodevelopmental disorders or familial exudative vitreoretinopathy. In particular, CTNNB1-related neurodevelopmental disorders have various phenotypes, and a genotype-phenotype relationship has not been established. We report two patients with CTNNB1-related neurodevelopmental disorder whose clinical features were similar to those of cerebral palsy, hindering diagnosis.

CTNNB1 in neurodevelopmental disorders

CTNNB1 is the gene that encodes β-catenin which acts as a key player in the Wnt signaling pathway and regulates cellular homeostasis. Most CTNNB1-related studies have been mainly focused on its role in cancer. Recently, CTNNB1 has also been found involved in neurodevelopmental disorders (NDDs), such as intellectual disability, autism, and schizophrenia. Mutations of CTNNB1 lead to the dysfunction of the Wnt signaling pathway that regulates gene transcription and further disturbs synaptic plasticity, neuronal apoptosis, and neurogenesis. In this review, we discuss a wide range of aspects of CTNNB1 and its physiological and pathological functions in the brain. We also provide an overview of the most recent research regarding CTNNB1 expression and its function in NDDs. We propose that CTNNB1 would be one of the top high-risk genes for NDDs. It could also be a potential therapeutic target for the treatment of NDDs.

Familial and syndromic forms of arachnoid cyst implicate genetic factors in disease pathogenesis

Arachnoid cysts (ACs) are the most common space-occupying lesions in the human brain and present significant challenges for clinical management. While most cases of ACs are sporadic, nearly 40 familial forms have been reported. Moreover, ACs are seen with increased frequency in multiple Mendelian syndromes, including Chudley-McCullough syndrome, acrocallosal syndrome, and autosomal recessive primary ciliary dyskinesia. These findings suggest that genetic factors contribute to AC pathogenesis. However, traditional linkage and segregation approaches have been limited in their ability to identify causative genes for ACs because the disease is genetically heterogeneous and often presents asymptomatically and sporadically. Here, we comprehensively review theories of AC pathogenesis, the genetic evidence for AC formation, and discuss a different approach to AC genomics that could help elucidate this perplexing lesion and shed light on the associated neurodevelopmental phenotypes seen in a significant subset of these patients.

Whole Exome Sequencing Identified two Novel Truncation Mutations in the CTNNB1 Gene Associated with Neurodevelopmental Disorder, Language Dysfunction, and Microcephaly in Chinese Children

Recently, the loss-of-function, heterozygous, and de novo mutations of the CTNNB1 gene have been proven to be partially responsible for intellectual disability in some patients. Herein, we report two unrelated children with neurodevelopmental disorder, abnormal facial features, speech impairments, microcephaly, and dystonia. Based on whole exome sequencing (WES), two new heterozygous and pathogenic mutations in exon 10 (c.1586dupA:p.Q530Afs*42) and exon 4 (c.257dup:p.Y86*) were identified in the CTNNB1 gene for the first time. These findings not only enrich the genetic spectrum of the CTNNB1 gene but also provide evidence for its role in neuronal development.

Startle Disease

Background and Objectives

Neurodevelopmental disorder with spastic diplegia and visual defect (NEDSDV) is a recently described rare syndrome caused by loss-of-function variations inCTNNB1gene which includes developmental delay, intellectual deficiency, visual defects, and other features. Startle disease is not present in the classic clinical description and has been reported in only 2 patients so far.

Methods

We report 12 cases of patients with NEDSDV who present an exaggerated startle response including 1 patient observed in our department and 11 patients recruited by addressing a questionnaire to the members of the Facebook group of families of patients with aCTNNB1pathogenic variant. We performed an EMG analysis of this abnormal startle response in 1 patient and a genotype-phenotype analysis of startle response in NEDSDV.

Results

All 12 patients presented exaggerated startle responses to an unexpected stimulus. They provoked falls in 8 patients, causing injuries in 3, and 3 patients were afraid to walk. This startle disorder corresponds to atypic hyperekplexia. No genotype to phenotype correlation has been found to differentiate NEDSDV with or without startle disease.

Discussion

Our data allow us to refine the phenotypic spectrum of patients affected byCTNNB1-related NEDSDV, suggesting that exaggerated startle reactions may be part of clinical features. A precise questioning on startle disorders should be performed systematically in these patients because they can lead to potentially traumatic falls, while effective treatments are available and can improve quality of life.CTNNB1study should be considered in patients with startle disease associated with intellectual deficiency.

CTNNB1 (β-CATENIN) VITREORETINOPATHY: IMAGING CHARACTERISTICS AND SURGICAL MANAGEMENT

PURPOSE

We report a patient with CTNNB1-associated vitreoretinopathy. We discuss imaging findings and surgical management.

METHODS

Case report.

RESULTS

An 18-month-old girl with microcephaly, failure to thrive, developmental delay, and chronic rhinitis presented with bilateral central and peripheral tractional retinal detachments and an anomalous retinal vasculature. She underwent multimodal imaging and genetic testing, and we discuss successful surgical management.

CONCLUSION

CTNNB1 mutations can cause a vision-threatening vitreoretinopathy. We recommend CTNNB1 to be considered as part of the workup of patients presenting with familial exudative vitreoretinopathy-like clinical findings, especially if there are systemic manifestations.

Identification of a novel de novo mutation in the CTNNB1 gene in an Iranian patient with intellectual disability

CTNNB1 encodes for the β-catenin protein, a component of the cadherin adhesion complex, which regulates cell-cell adhesion and gene expression in the canonical Wnt signaling pathway. Mutations in CTNNB1 have been reported to be associated with cancer and mental disorders. Recently, loss-of-function mutations in CTNNB1 have been observed in patients with intellectual disability and some other clinical manifestations including motor and language delays, microcephaly, and mild visual defects. We report an 8-year-old Iranian girl with intellectual disability, hypotonia, impaired vision such as vitreomacular adhesion, motor delay, and speech delay. A novel, de novo nonsense mutation (c.1014G > A; p.Trp338Ter) in exon 7 of the CTNNB1 (NM_001904) gene was detected and confirmed by whole-exome sequencing and Sanger sequencing, respectively. This study helps to expand the growing list of loss-of-function mutations known in the CTNNB1 gene.

Advances in hyperekplexia and other startle syndromes

Startle, a basic alerting reaction common to all mammals, is described as a sudden involuntary movement of the body evoked by all kinds of sudden and unexpected stimulus. Startle syndromes are heterogeneous groups of disorders with abnormal and exaggerated responses to startling events, including hyperekplexia, stimulus-induced disorders, and neuropsychiatric startle syndromes. Hyperekplexia can be attributed to a genetic, idiopathic, or symptomatic cause. Excluding secondary factors, hereditary hyperekplexia, a rare neurogenetic disorder with highly genetic heterogeneity, is characterized by neonatal hypertonia, exaggerated startle response provoked by the sudden external stimuli, and followed by a short period of general stiffness. It mainly arises from defects of inhibitory glycinergic neurotransmission. GLRA1 is the major pathogenic gene of hereditary hyperekplexia, along with many other genes involved in the function of glycinergic inhibitory synapses. While about 40% of patients remain negative genetic findings. Clonazepam, which can specifically upgrade the GABARA1 chloride channels, is the main and most effective administration for hereditary hyperekplexia patients. In this review, with the aim at enhancing the recognition and prompting potential treatment for hyperekplexia, we focused on discussing the advances in hereditary hyperekplexia genetics and the expound progress in pathogenic mechanisms of the glycinergic-synapse-related pathway and then followed by a brief overview of other common startle syndromes.

Dissecting Molecular Genetic Mechanisms of 1q21.1 CNV in Neuropsychiatric Disorders

Pathogenic copy number variations (CNVs) contribute to the etiology of neurodevelopmental/neuropsychiatric disorders (NDs). Increased CNV burden has been found to be critically involved in NDs compared with controls in clinical studies. The 1q21.1 CNVs, rare and large chromosomal microduplications and microdeletions, are detected in many patients with NDs. Phenotypes of duplication and deletion appear at the two ends of the spectrum. Microdeletions are predominant in individuals with schizophrenia (SCZ) and microcephaly, whereas microduplications are predominant in individuals with autism spectrum disorder (ASD) and macrocephaly. However, its complexity hinders the discovery of molecular pathways and phenotypic networks. In this review, we summarize the recent genome-wide association studies (GWASs) that have identified candidate genes positively correlated with 1q21.1 CNVs, which are likely to contribute to abnormal phenotypes in carriers. We discuss the clinical data implicated in the 1q21.1 genetic structure that is strongly associated with neurodevelopmental dysfunctions like cognitive impairment and reduced synaptic plasticity. We further present variations reported in the phenotypic severity, genomic penetrance and inheritance.

Cell-type and fetal-sex-specific targets of prenatal alcohol exposure in developing mouse cerebral cortex

Prenatal alcohol exposure (PAE) results in cerebral cortical dysgenesis. Single-cell RNA sequencing was performed on murine fetal cerebral cortical cells from six timed pregnancies, to decipher persistent cell- and sex-specific effects of an episode of PAE during early neurogenesis. We found, in an analysis of 38 distinct neural subpopulations across 8 lineage subtypes, that PAE altered neural maturation and cell cycle and disrupted gene co-expression networks. Whereas most differentially regulated genes were inhibited, particularly in females, PAE also induced sex-independent neural expression of fetal hemoglobin, a presumptive epigenetic stress adaptation. PAE inhibited Bcl11a, Htt, Ctnnb1, and other upstream regulators of differentially expressed genes and inhibited several autism-linked genes, suggesting that neurodevelopmental disorders share underlying mechanisms. PAE females exhibited neural loss of X-inactivation, with correlated activation of autosomal genes and evidence for spliceosome dysfunction. Thus, episodic PAE persistently alters the developing neural transcriptome, contributing to sex- and cell-type-specific teratology.

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The neurogenic murine fetal cortex contains about 33 distinct cell subtypes

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Prenatal Alcohol Exposure (PAE) resulted in sex-specific alterations in developmental trajectory and cell cycle

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PAE females exhibited neural loss of X-inactivation and spliceosomal dysfunction

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PAE induced sex-independent neural expression of fetal hemoglobin gene transcripts

Mapping the molecular and cellular complexity of cortical malformations

The cerebral cortex is an intricate structure that controls human features such as language and cognition. Cortical functions rely on specialized neurons that emerge during development from complex molecular and cellular interactions. Neurodevelopmental disorders occur when one or several of these steps is incorrectly executed. Although a number of causal genes and disease phenotypes have been identified, the sequence of events linking molecular disruption to clinical expression mostly remains obscure. Here, focusing on human malformations of cortical development, we illustrate how complex interactions at the genetic, cellular, and circuit levels together contribute to diversity and variability in disease phenotypes. Using specific examples and an online resource, we propose that a multilevel assessment of disease processes is key to identifying points of vulnerability and developing new therapeutic strategies.

Missense variants in CTNNB1 can be associated with vitreoretinopathy-Seven new cases of CTNNB1-associated neurodevelopmental disorder including a previously unreported retinal phenotype

BACKGROUND

CTNNB1 (MIM 116806) encodes beta-catenin, an adherens junction protein that supports the integrity between layers of epithelial tissue and mediates intercellular signaling. Recently, various heterozygous germline variants in CTNNB1 have been associated with human disease, including neurodevelopmental disorder with spastic diplegia and visual defects (MIM 615075) as well as isolated familial exudative vitreoretinopathy without developmental delays or other organ system involvement (MIM 617572). From over 40 previously reported patients with CTNNB1-related neurodevelopmental disorder, many have had ocular anomalies including strabismus, hyperopia, and astigmatism. More recently, multiple reports indicate that these abnormalities are associated with the presence of vitreoretinopathy.

METHODS

We gathered a cohort of three patients with CTNNB1-related neurodevelopmental disorder, recruited from both our own clinic and referred from outside providers. We then searched for a clinical database comprised of over 12,000 exome sequencing studies to identify and recruit four additional patients.

RESULTS

Here, we report seven new cases of CTNNB1-related neurodevelopmental disorder, all harboring de novo variants, six of which were previously unreported. All patients but one presented with a spectrum of ocular abnormalities and one patient, who was found to carry a missense variant in CTNNB1, had notable vitreoretinopathy.

CONCLUSIONS

Our findings suggest ophthalmologic screening should be performed in all patients with CTNNB1 variants.

A de novo CTNNB1 Novel Splice Variant in an Adult Female with Severe Intellectual Disability

The catenin beta-1 (CTNNB1) gene, encoding a sub-unit of the cadherin/catenin protein complex that is involved in the Wnt signalling pathway important for proper interneuron development, is considered to be causative for the rare autosomal dominant mental retardation syndrome, formerly called MRD19 but later renamed neurodevelopmental disorder with spastic diplegia and visual defects (NEDSDV). Its main characteristics are moderate to severe intellectual disability (ID), disruptive autistic behaviours, microcephaly, absent or limited speech, facial dysmorphisms, peripheral hypertonia/spasticity, motor delay and visual defects. So far, 35 patients have been reported with a de novo loss-of-function variant in CTNNB1. In two other patients, a deletion comprising the full gene was found. Four out of the 37 patients were of adult age (range: 27–51 years), while the majority was infant or adolescent (range: 0–20 years). Here, a 32-year-old severely intellectually disabled female patient is described in whom exome sequencing disclosed a de novo heterozygous splice site variant in the CTNNB1 gene [Chr3(GRCh37): g.41267064G>T; NM_001904.3: 23. c.734+1G>T; r. spl?]. Somatic investigation disclosed significant microcephaly and minor facial dysmorphisms. Neurological examination demonstrated severe kyphoscoliosis, distal spastic tetraparesis, especially of the legs with increased tendon reflexes and bilateral Babinski sign, resulting in severely impaired walking capability with a broad-based gait. Apart from strabismus, no ophthalmological abnormalities were found. Here, the reported variant in the CTNNB1 gene was not published earlier nor is included in the international databases. This specific variant is considered to be causative for the severe ID, autism and the somato-neurological phenotype of the patient and corresponds with a diagnosis of NEDSDV.

Case Report: A de novo CTNNB1 Nonsense Mutation Associated With Neurodevelopmental Disorder, Retinal Detachment, Polydactyly

CTNNB1 gene mutation was firstly reported related to intellectual disability in 2012, to explore the clinical phenotype and genotype characteristics of CTNNB1 mutation, we collected and analyzed the clinical data of a child with a neurodevelopmental disorder caused by a mutation of CTNNB1. The child had dysmorphic features, microcephaly, hypotonia, polydactyly, retinal detachment, and neurodevelopmental disorder, with a de novo mutation of CTNNB1 c.1603C > T, p.R535X. The patient was diagnosed as Neurodevelopmental disorder with spastic diplegia and visual defects (NEDSDV) and was given rehabilitation training. After 4 months of rehabilitation training, she improved in gross motor function. We found that CTNNB1 mutation can cause neurodevelopmental disorder, which could be accompanied by retinal detachment and polydactyly. The retinal detachment had only been reported in two Asian patients, and we firstly reported the phenotype of polydactyly in the CTNNB1 mutation. This report not only helps to expand the clinical phenotype spectrum of the CTNNB1 gene mutation but also prompts a new insight into genetic diagnosis in patients with a neurodevelopmental disorder, retinal detachment, and polydactyly.

Learning impairments and molecular changes in the brain caused by β-catenin loss

Intellectual disability (ID), defined as IQ<70, occurs in 2.5% of individuals. Elucidating the underlying molecular mechanisms is essential for developing therapeutic strategies. Several of the identified genes that link to ID in humans are predicted to cause malfunction of β-catenin pathways, including mutations in CTNNB1 (β-catenin) itself. To identify pathological changes caused by β-catenin loss in the brain, we have generated a new β-catenin conditional knockout mouse (β-cat cKO) with targeted depletion of β-catenin in forebrain neurons during the period of major synaptogenesis, a critical window for brain development and function. Compared with control littermates, β-cat cKO mice display severe cognitive impairments. We tested for changes in two β-catenin pathways essential for normal brain function, cadherin-based synaptic adhesion complexes and canonical Wnt (Wingless-related integration site) signal transduction. Relative to control littermates, β-cat cKOs exhibit reduced levels of key synaptic adhesion and scaffold binding partners of β-catenin, including N-cadherin, α-N-catenin, p120ctn and S-SCAM/Magi2. Unexpectedly, the expression levels of several canonical Wnt target genes were not altered in β-cat cKOs. This lack of change led us to find that β-catenin loss leads to upregulation of γ-catenin (plakoglobin), a partial functional homolog, whose neural-specific role is poorly defined. We show that γ-catenin interacts with several β-catenin binding partners in neurons but is not able to fully substitute for β-catenin loss, likely due to differences in the N-and C-termini between the catenins. Our findings identify severe learning impairments, upregulation of γ-catenin and reductions in synaptic adhesion and scaffold proteins as major consequences of β-catenin loss.

Germline Mutations in CTNNB1 Associated With Syndromic FEVR or Norrie Disease

Purpose

Germline and somatic mutations in CTNNB1 have been found in different types of human diseases. This follow-up study aimed to identify causative germline mutations in CTNNB1 and their associated ocular phenotypes through a comparative analysis of whole-exome sequencing data.

Methods

Annotated sequence variations in CTNNB1 were selected from in-house data from whole-exome sequencing of genomic DNA prepared from leucocytes of 3280 unrelated probands with different forms of eye diseases. Potentially pathogenic variants in CTNNB1 were analyzed by multistep bioinformatics analyses. Clinical data from probands with pathogenic variants in CTNNB1 were collected, and potential genotype-phenotype correlations were analyzed.

Results

Eleven rare variants that potentially affect the coding regions of CTNNB1 were detected in 11 of the 3280 samples, and four variants were considered to be potentially pathogenic. All four mutations, namely, c.999delC (p.Tyr333*), c.1104delT (p.His369Thrfs*2), c.1738_1742delinsACA (p.Leu580Thrfs*28), and c.1867C>T (p.Gln623*), were heterozygotes and considered to have a germline origin. Three of the four mutations are de novo mutations, and the status of the remaining mutation is unavailable. All four probands had the same class of closely related ocular diseases: one proband had FEVR, and three probands had Norrie-like retinopathy. The molecular results indicated that three probands showed systemic anomalies, as demonstrated by a follow-up survey, but relevant information for the remaining proband was unavailable.

Conclusions

The data suggest that germline truncating mutations in CTNNB1 cause autosomal dominant syndromic FEVR or Norrie disease. Patients with mutations in CTNNB1, KIF11, or NDP may have similar or overlapping phenotypes, but this phenomenon needs to be studied further.

Whole exome sequencing reveals a mutation in ARMC9 as a cause of mental retardation, ptosis, and polydactyly

Intellectual disability (ID) refers to deficits in mental abilities, social behavior, and motor skills to perform activities of daily living as compared to peers. Numerous genetic and environmental factors may be responsible for ID. We report on elucidation of molecular basis for syndromic ID associated with ptosis, polydactyly, and MRI features suggestive of Joubert syndrome using homozygosity mapping followed by exome sequencing. The analysis revealed a novel synonymous variation p.T293T (c.879G>A) which leads to a splicing defect in ARMC9 gene. The variant is present in conserved region of ARM domain of ARMC9 protein, which is predicted to form a platform for protein interaction. This domain is likely to be altered in patient due to splicing defect caused by this synonymous variation. Our report of variant in ARMC9 Leading to Joubert syndrome phenotype (JS30), elucidates the genetic heterogeneity of Joubert syndrome, and expands the gene list for ciliopathies.

A novel compound mutation in GLRA1 cause hyperekplexia in a Chinese boy- a case report and review of the literature

Background

The pathogenesis of hereditary hyperekplexia is thought to involve abnormalities in the glycinergic neurotransmission system, the most of mutations reported in GLRA1. This gene encodes the glycine receptor α1 subunit, which has an extracellular domain (ECD) and a transmembrane domain (TMD) with 4 α-helices (TM1–TM4).

Case presentation

We investigated the genetic cause of hyperekplexia in a Chinese family with one affected member. Whole-exome sequencing of the 5 candidate genes was performed on the proband patient, and direct sequencing was performed to validate and confirm the detected mutation in other family members. We also review and analyse all reported GLRA1 mutations. The proband had a compound heterozygous GLRA1 mutation that comprised 2 novel GLRA1 missense mutations, C.569C > T (p.T190 M) from the mother and C.1270G > A (p.D424N) from the father. SIFT, Polyphen-2 and MutationTaster analysis identified the mutations as disease-causing, but the parents had no signs of hyperekplexia. The p.T190 M mutation is located in the ECD, while p.D424N is located in TM4.

Conclusions

Our findings contribute to a growing list GLRA1 mutations associated with hyperekplexia and provide new insights into correlations between phenotype and GLRA1 mutations. Some recessive mutations can induce hyperekplexia in combination with other recessive GLRA1 mutations. Mutations in the ECD, TM1, TM1-TM2 loop, TM3, TM3-TM4 loop and TM4 are more often recessive and part of a compound mutation, while those in TM2 and the TM2-TM3 loop are more likely to be dominant hereditary mutations.

Electronic supplementary material

The online version of this article (10.1186/s12881-017-0476-6) contains supplementary material, which is available to authorized users.

Exome sequencing identifies a de novo mutation of CTNNB1 gene in a patient mainly presented with retinal detachment, lens and vitreous opacities, microcephaly, and developmental delay: Case report and literature review

RATIONALE

The CTNNB1 (β-catenin) gene is well known for its crucial role in cell adhesion and the Wnt-signaling pathway. Previous studies have shown that gain-of-function mutations in the CTNNB1 gene contribute to the occurrence and development of a variety of carcinomas in humans. Recently, de novo, heterozygous, loss-of-function mutations of the CTNNB1 gene were found that partially explain intellectual disability in some patients. Other major clinical symptoms in these patients included microcephaly, abnormal facial features, motor delays, speech impairments, and deformities of the hands and feet. In addition, approximately 75% of these patients had mild visual defects, such as astigmatism, hyperopia, or strabismus PATIENT CONCERNS:: A 15-month-old Chinese boy, presenting with retinal detachment, lens and vitreous opacities, hypertonia of the extremities, mild thumb adduction, microcephaly, and developmental delay, is described. Targeted gene sequencing using an ophthalmic gene panel was performed to test for familial exudative vitreoretinopathy; however, the pathogenic gene was not found.

INTERVENTIONS

Genomic DNA analysis was performed to search for causing mutations.

DIAGNOSES AND OUTCOMES

Whole-exome sequencing revealed a novel nonsense variation in exon 11 of the CTNNB1 gene (c.1672C>T, p.Gln558X). Sanger sequencing of the patient and his parent confirmed this mutation and demonstrated it to be de novo. To the best of our knowledge, this is the first case report of a loss-of-function mutation of the CTNNB1 gene in an Asian population.

LESSONS

Severe ophthalmic phenotype has not well been connected with loss of functional mutation of CTNNB1 gene. Our finding expands the mutant spectrum of CTNNB1 gene and adds new understanding of the phenotype.

Targeted sequencing identifies 91 neurodevelopmental-disorder risk genes with autism and developmental-disability biases

Gene-disruptive mutations contribute to the biology of neurodevelopmental disorders (NDDs), but most of the related pathogenic genes are not known. We sequenced 208 candidate genes from >11,730 cases and >2,867 controls. We identified 91 genes, including 38 new NDD genes, with an excess of de novo mutations or private disruptive mutations in 5.7% of cases. Drosophila functional assays revealed a subset with increased involvement in NDDs. We identified 25 genes showing a bias for autism versus intellectual disability and highlighted a network associated with high-functioning autism (full-scale IQ >100). Clinical follow-up for NAA15, KMT5B, and ASH1L highlighted new syndromic and nonsyndromic forms of disease.

Clinical features associated with CTNNB1 de novo loss of function mutations in ten individuals

Loss of function mutations in CTNNB1 have been reported in individuals with intellectual disability [MIM #615075] associated with peripheral spasticity, microcephaly and central hypotonia, suggesting a recognisable phenotype associated with haploinsufficiency for this gene. Trio based whole exome sequencing via the Deciphering Developmental Disorders (DDD) study has identified eleven further individuals with de novo loss of function mutations in CTNNB1. Here we report detailed phenotypic information on ten of these. We confirm the features that have been previously described and further delineate the skin and hair findings, including fair skin and fair and sparse hair with unusual patterning.