DMPK and myotonic dystrophy type 1: This includes DMPK, for which small expansions (50–150 repeats) cause mild myotonic dystrophy type 1 and large expansions (>1000 repeats) cause more severe disease, and spinocerebellar ataxia type 36 (NOP56), for which expansions larger than 650 repeats are considered pathogenic and repeat sizes of 15–650 are considered intermediate and variants of uncertain significance.