Question

19. Copy number variants (CNVs) comprise the most common form of structural variation in the genome, and can be inherited or de novo. CNVs in specific regions of the genome are associated with increased risk of autism spectrum disorders (ASDs). Recent studies have been conditioned on specific individual genes and CNVs, such that the spectrum of biological and clinical findings associated with those genomic events can be better. One of the more extensively studied ASD-associated CNVs, is a duplication or deletion at a particular chromosomal locus, 16p11.2, that contains hundreds of genes that could influence ASDs. Explain why a deletion in this region could lead to ASD (think in terms of influence the CNV would have on a single gene product? (5 points) Explain how these two alternative scenarios could be possible: A) A duplication in this region helped prevent ASDs. (5 points) B) A duplication in this region led to an increase in ASDs. (S points)

Answer 1

Autism spectrum disorder(ASD), is a neurodevelopmental disorders in the DSM-5. 16p11,2Deletion syndrome lead to ASD is due to deletion in small piece of chromosome 16. It causes developmental delay and intellectual disability.

Deletion Breaks in Chromosome <l.. .. Deleted Genetic Material U.S. National Library of Medicine

Copy-number variations (CNV) changes the genome of an organism by duplication or deletion of a chromosomal region.  CNV on the chromosome 16 effects on the behavior of affected individuals, it is because of  interactions between core genetic loci and additional factors. When genes code for cellular signaling molecules, are affected, it can lead to disturbances of the nervous system. This malfunctioning of the nervous system is caused due to reduced dosage in the intracellular signaling pathway. And it lead to autism spectrum disorders.

A small changes or microduplication doesn't affects the indiviual behavior, and not compulsory at all the time it will lead to ASD.

Only 50% progeny of affected indiviual recieved this syndrome. It can be caused due deletion or duplication in that chromosome.