Background: Sleep disturbance is a frequent comorbidity in children with autism spectrum disorder (ASD), affecting an estimated 40-80% of cases. Previous reports have shown relationships between several circadian rhythm-related genes and sleep problems in ASD. The purpose of the present study was to relate variation in and around melatonin synthesis and suprachiasmatic nucleus genes to sleep problems in a large sample of children with ASD.
Method: This secondary analysis used existing genotypic and phenotypic data for 2,065 children, aged 4-18 years, from the Simons Simplex Collection (SSC). Sleep problems were measured with the SSC Sleep Interview. Expression quantitative trait loci and single nucleotide polymorphisms in 25 circadian genes were chosen primarily for their impact on expression levels of target genes in the brain. Associations between variants and composite sleep problems, nighttime problems, daytime problems, and sleep duration problems were calculated using logistic regression analysis. Age, sex, nonverbal IQ, ASD severity, gastrointestinal distress, seizures, and ancestry were included as covariates. Transmission disequilibrium tests were performed to test for overtransmission of alleles in the same variants.
Results: No significant associations or transmission disequilibrium were found between gene variants and sleep problems in this sample of children with ASD.
Conclusion: Variation in expression of investigated genes in the melatonin synthesis and suprachiasmatic nucleus pathways did not have notable impacts on sleep problems in this large sample of children with ASD. Future research could explore translational and posttranslational effects of these genes or the effects of genes in other sleep-homeostasis pathways on sleep patterns.
Keywords: Simons Simplex Collection; autism spectrum disorder; melatonin; suprachiasmatic nucleus; transmission disequilibrium.