SMCHD1 and myoclonus-dystonia syndrome: Similar observations are made for three other contiguous gene deletions: the deletion of >20 genes, including NKX2-1 in a proband with balance problems, myoclonus, chorea and dystonia; a deletion of SGCE among 15 other genes in a proband with myoclonic dystonia; and a deletion affecting seven genes including SMCHD1 in a individual with muscular dystrophy only.