Previous studies focusing on candidate genes and chromosomal regions identified several copy number variations (CNVs) associated with increased risk of ASD. Reasons for a possibly higher prevalence of ASD in Saudi Arabia are not clear but could relate in part to differences in diagnostic practice, higher consanguinity rates, a founder effect, or unidentified environmental risk factors. The exact prevalence of ASD in Saudi Arabia is still undetermined, but one rough estimate is 18 per 10,000, slightly higher than 13 per 10,000 reported in developed countries. Current prevalence estimates in the United States are 0.1-0.2% of live births for autism and 0.6% for ASD. We identified a potential ASD locus (9p24.3 to 9p23) that may encompass gene(s) contributing to autism or ASD.Īutism spectrum disorders (ASD), including autism, are neuro-developmental disorders characterized by impairment in social and communication skills together with stereotyped and repetitive behavior and/or a restricted range of interests. The ASD candidate locus contained 34 genes that may contribute to the autistic features in this patient. Detailed analysis of the duplicated region revealed: i) an area extending from 9p22.3 to 9p22.2 that was previously identified as a critical region for the 9p duplication syndrome ii) a region extending from 9p22.1 to 9p13.1 that was previously reported to be duplicated in a normal individual and iii) a potential ASD locus extending from 9p24.3 to 9p23.
Apart from the marker chromosome, no other copy number variations (CNVs) were detected in the patient or her family. This mosaic 9p duplication was detected only in the proband and not in the parents, her four unaffected siblings, or 258 ethnic controls. Array CGH analysis showed that the marker chromosome originated from 9p24.3 to 9p13.1 with a gain of 38.9 Mb. We describe a 17-year-old girl with autism, severe mental retardation, epilepsy, and partial 9p duplication syndrome features in whom GTG-banded chromosome analysis revealed a female karyotype with a marker chromosome in 69% of analyzed metaphases. Previous studies focusing on candidate genes and chromosomal regions identified several copy number variations (CNVs) associated with increased risk of autism or autism spectrum disorders (ASD).
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