In this week's Nature Genetics, a group of industry and academia investigators report their discovery of 15 genomic regions associated with major depressive disorder (MDD) in people of European descent, offering new insights into the genetic underpinnings of the disorder. The researchers performed a genome-wide association study in more than 121,000 individuals with history of MDD and in more than 338,000 people with no history of depression — all of whom are customers of consumer genetics firm 23andMe. The study revealed 15 genomic regions with statistically significant associations with MDD, while a preliminary analysis found that these regions are enriched for genes expressed in the nervous system, including ones involved in neurodevelopment. GenomeWeb has more on this study, here.
And in npj Genomic Medicine, a multi-institute research team publishes the largest whole-genome sequencing study to date in autism spectrum disorder, revealing a previously unknown role for certain maternal mutations in the condition. By studying germline and somatic de novo mutations in 200 autistic children with parents not affected by the disorder, they found that a majority of the germline mutations originate from the father. Meanwhile, clustered de novo mutations originate from the mother and are frequently located next to de novo copy number variations — segments of the genome that were spontaneously deleted on the maternal chromosome. The team suggests that the differences in paternal and maternal chromosome de novo mutations may be caused by sex-based differences in DNA repair during spermatogenesis and oogenesis. They also found that coding and non-coding de novo mutations in autism are enriched in genes involved in synaptic transmission, gene expression, and chromatin organization.