Williams syndrome (WS) is a neurodevelopmental disorder caused by deletions in the 7q11.23 chromosomal region. Individuals with WS show developmental delays, learning disabilities and excessively social behavior. Interestingly, individuals with duplications of this same chromosomal region display a symmetrically opposite phenotype with regard to social behavior. This genomic segment therefore offers a unique opportunity to understand the molecular underpinnings of social behaviors.
A number of autism risk factors converge on one cellular pathway: abnormal remodeling of the cell's structural systems through the signaling protein Rho, says SFARI’s associate director for research, Alan Packer.
Duplication of a small segment of human chromosome 7 has been found in some children with autism. Lucy Osborne and her colleagues at the University of Toronto aim to understand the effects of duplication of this region, 7q11.23, on the growth and function of the brain. They plan to study this using a mouse model with a similar duplication.
Autism can be caused by a number of different genetic alterations, some of which result in known syndromes. In 2011, a genetic study of a large sample of children in the Simons Simplex Collection, a database of genetic and clinical information from families that include one child with autism, showed a strong association between duplication of the Williams syndrome chromosomal region (7q11.23) and autism.
Dysregulation of the intracellular signaling pathway RAS, a risk factor for idiopathic autism, may provide a unifying theory of the disorder. Although this is not an altogether new hypothesis, several new findings have strengthened the evidence for it considerably.
Some overlap between 7q11.23 duplication syndrome and autism spectrum disorder has been reported in a large cohort of children. Individuals with duplication of this region show features commonly found in individuals with autism, such as speech delay.