Molecular characterization of NRXN1 deletions from 19,263 clinical microarray cases identifies exons important for neurodevelopmental disease expression.

PURPOSE: The purpose of the current study was to assess the penetrance of NRXN1 deletions. METHODS: We compared the prevalence and genomic extent of NRXN1 deletions identified among 19,263 clinically referred cases to that of 15,264 controls. The burden of additional clinically relevant copy-number variations (CNVs) was used as a proxy to estimate the relative penetrance of NRXN1 deletions. RESULTS: We identified 41 (0.21%) previously unreported exonic NRXN1 deletions ascertained for developmental delay/intellectual disability that were significantly greater than in controls (odds ratio (OR) = 8.14; 95% confidence interval (CI): 2.91-22.72; P < 0.0001). Ten (22.7%) of these had a second clinically relevant CNV. Subjects with a deletion near the 3' end of NRXN1 were significantly more likely to have a second rare CNV than subjects with a 5' NRXN1 deletion (OR = 7.47; 95% CI: 2.36-23.61; P = 0.0006). The prevalence of intronic NRXN1 deletions was not statistically different between cases and controls (P = 0.618). The majority (63.2%) of intronic NRXN1 deletion cases had a second rare CNV at a prevalence twice as high as that for exonic NRXN1 deletion cases (P = 0.0035). CONCLUSIONS: The results support the importance of exons near the 5' end of NRXN1 in the expression of neurodevelopmental disorders. Intronic NRXN1 deletions do not appear to substantially increase the risk for clinical phenotypes.Genet Med 19 1, 53-61.

Consensus recommendations on altered sensory functioning in Phelan-McDermid syndrome.

Altered sensory functioning is often observed in individuals with SHANK3 related Phelan-McDermid syndrome (PMS). Compared to typically developing individuals and individuals with an autism spectrum disorder, it has been suggested that there are distinctive features of sensory functioning in PMS. More hyporeactivity symptoms and less hyperreactivity and sensory seeking behaviour are seen, particularly in the auditory domain. Hypersensitivity to touch, possible overheating or turning red easily and reduced pain response are often seen. In this paper the current literature on sensory functioning in PMS is reviewed and recommendations for caregivers, based on consensus within the European PMS consortium, are given.

Parental perspectives on Phelan-McDermid syndrome: Results of a worldwide survey.

Phelan-McDermid syndrome (PMS) is a rare neurodevelopmental disorder characterised by hypotonia, speech problems, intellectual disability and mental health issues like regression, autism and mood disorders. In the development, implementation and dissemination of a new clinical guideline for a rare genetic disorder like PMS, the parental experienced perspective is essential. As information from literature is scarce and often conflicting the European Phelan-McDermid syndrome guideline consortium created a multi-lingual survey for parents of individuals with PMS to collect their lived experiences with care needs, genotypes, somatic issues, mental health issues and parental stress. In total, we analysed 587 completed surveys from 35 countries worldwide. Based on parental reporting, PMS appeared to be caused by a deletion of chromosome 22q13.3 in 78% (379/486) of individuals and by a variant in the SHANK3 gene in 22% (107/486) of the individuals. Parents reported a wide variety of developmental, neurological, and other clinical issues in individuals with PMS. The most frequently experienced issues were related to speech and communication, learning disabilities/intellectual disability, and behaviour. While most reported issues were present across all age groups and genotypes, the prevalence of epilepsy, lymphoedema, and mental health issues do appear to vary with age. Developmental regression also appeared to begin earlier in this cohort than described in literature. Individuals with PMS due to a 22q13.3 deletion had a higher rate of kidney issues and lymphoedema compared to individuals with SHANK3 variants. Parental stress was high, with specific contributing factors being child and context related in accordance with the PMS phenotype. The survey results led to various validated recommendations in the European PMS guideline including an age specific surveillance scheme, specific genetic counselling, structured healthcare evaluations on sleep and communication and a focus on family well-being.