No Correlation between X Chromosome Inactivation Pattern and Autistic Spectrum Disorders in an Italian Cohort of Patients

Autistic spectrum disorders (ASD) occur more frequently in males, suggesting a major pathogenic role for genes located on the X-chromosome. The analysis of X chromosome inactivation (XCI) pattern may help to identify XCI skewing in those families in which such genes are involved, even without identifying the specific genetic mutation. In order to identify such families, we determined the XCI pattern in 40 females with ASD and 58 mothers of children with ASD, as well as in 80 matched control females. We could not detect any skewing in mothers of ASD children nor in ASD females. However, it cannot be ruled out that a different XCI pattern is present in the brain or that other, unexplored X-linked loci might undergo segmental or locus specific XCI skewing.