Sexual Dimorphism in Telomere Length in Childhood Autism

Abstract

Autism spectrum disorders (ASD) are lifelong heterogeneous set of neurodevelopmental conditions with strikingly profound male prevalence. Differences in sex biology and hormones are thought to play key roles in ASD prevalence and outcome, but the underlying molecular mechanisms responsible for ASD sex-differential risk are not well understood. Two recent studies reported a significant association between shortened telomere length (TL) and autistic children. However, the role of gender bias has been overlooked. Here, we carefully examined the status of average TL among nonsyndromic male and female children with autism, and we also took a close look at the data from earlier reports. A total of 58 children were recruited for this project, including 24 apparently nonsyndromic autistic children (14 males and 10 females), their healthy siblings (n = 10), and 24 sex-, age, and location-matched healthy controls. Relative TLs (RTL) were assessed by the monochrom multiplex quantitative polymerase chain reaction (MMQPCR) technique, using genomic DNA extracted from saliva samples. Data analysis showed that gender and age had strong impacts on average RTLs among the study groups. In a sex stratified manner, autistic male children had significantly shorter average RTL than their female counterparts. Only male children with autism showed a homogeneous pattern of shorter RTLs compared with their respective healthy controls. Our findings are indicative of a sexually dimorphic pattern of TL in childhood autism. The data presented here have important implications for the role of telomere biology in the molecular mechanisms responsible for ASD male bias prevalence and etiology.