The Role of Ultra-Rare Coding Variants In ADHD

Attention-Deficit Hyperactivity Disorder (ADHD) is a highly heritable childhood behavioural disorder affecting 3-6% of school-age children, and has a heritability of around 0.80. The SNP heritability, estimating the amount of risk attributed to common genetic variation, has been estimated to 0.22. The difference between SNP heritability and total heritability indicates that the genetic component of ADHD most likely also includes effects of rare variants. The role of ultra-rare deleterious variants has been established for schizophrenia and autism, but the role of these variants in ADHD remains unknown.