DNMT3A and overgrowth syndrome: The first report of DNMT3A overgrowth syndrome (DOS, also called Tatton–Brown–Rahman Syndrome; TBRS; MIM 615879) described a syndrome of increased growth, defined as height and/or head circumference at least two standard deviations above the mean, associated with facial dysmorphism and intellectual disability occurring in patients with de novo heterozygous germline mutations in DNMT3A1.