Advanced genomic sequencing is uncovering hidden autism gene variants, shedding light on the genetic complexities of the disorder. Researchers report that long-read genome sequencing can now identify complex structural mutations that conventional DNA sequencing methods often miss.
Autism spectrum disorder has a significant genetic basis, but much of its heritability remains unexplained. Traditional short-read sequencing analyzes DNA in small fragments, obscuring larger structural rearrangements. Long-read sequencing, however, analyzes much larger DNA segments, enabling the mapping of complex genomic structures and the identification of previously undetectable variants.
The study involved 267 individuals from 63 families. By integrating long-read and short-read sequencing data, researchers identified over 44,000 structural variants, with approximately 60% being novel. This advanced method increased the detection of gene-disrupting structural variants by 33% and tandem repeat variants by 38%.
Investigators also discovered previously undescribed complex structural rearrangements. Combining structural variant analysis with DNA methylation data allowed them to identify deletions in imprinted genes and examine how intermediate tandem repeat expansions influence the FMR1 promoter, a region associated with intellectual disability.
These findings suggest that long-read sequencing could revolutionize the study of autism gene variants by revealing previously invisible genomic changes. Researchers estimate that rare structural variants, tandem repeats, and damaging single nucleotide variants collectively account for 7.4% of autism spectrum disorder heritability.
Improved detection of these gene variants may advance the understanding of autism's biological mechanisms and support the development of more precise diagnostic tools, potentially closing the "missing heritability" gap and guiding personalized approaches to autism research and clinical care.