Whole genome analysis of rare deleterious variants adds further evidence to BRSK2 and other risk genes in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition with a strong genetic component in which rare variants contribute significantly to risk. We have performed whole genome and/or exome sequencing (WGS and WES) and SNP-array analysis to identify both rare sequence and copy number variants (SNVs and CNVs) in 435 individuals from 116 ASD families. We identified 37 rare potentially damaging de novo SNVs (pdSNVs) in cases (n = 144). Interestingly, two of them (one stop-gain and one missense variant) occurred in the same gene, BRSK2. Moreover, the identification of 9 severe de novo pdSNVs in genes not previously implicated in ASD (RASAL2, RAP1A, IRX5, SLC9A1, AGPAT3, MGAT3, RAB8B, MGAT5B, YME1L1), highlighted novel candidates. Potentially damaging CNVs (pdCNVs) provided support to the involvement of inherited variants in PHF3, NEGR1, TIAM1 and HOMER1 in neurodevelopmental disorders (NDD), although mostly acting as susceptibility factors with incomplete penetrance. Interpretation of identified pdSNVs/pdCNVs according to the ACMG guidelines led to a molecular diagnosis in 19/144 cases, but this figure represents a lower limit and is expected to increase thanks to further clarification of the role of likely pathogenic variants in new ASD/NDD candidates. In conclusion, our study strengthens the role of BRSK2 and other neurodevelopmental genes in ASD risk, highlights novel candidates and contributes to characterize the allelic diversity, mode of inheritance and phenotypic impact of de novo and inherited risk variants in ASD/NDD genes.

[Normal spirometric values in the Sicilian population]

Principal spirometric parameters have been measured in a sample group of 1641 male subjects. Due to the significant difference in values often found when using the standards proposed by CECA (1983) (particularly in the medico-legal field) in order to obtain reference values as close as possible to the local norm the chosen subjects are clinically and functionally healthy and come from different parts of Sicily. The regression plots obtained using three independent variables (age, weight, height) other than demonstrating a good affinity with the original sample and an elevated predictivity level, underline the difference between obtained reference values and European ones (higher for VC and FEV 1; lower for FRC and RV) even though evolutive trend and ageing overlap. The above mentioned difference, found also for some parameters (VC and FEV 1) using normal Italian standards can be explained; not only by different evaluations of normal conditions, respiratory risk, smoking etc., but also by the existence of a different ethnic constitution which influences in various ways the ventilatory parameters.