Tatton-Brown-Rahman syndrome (TBRS) is a rare genetic disorder caused by mutations within the DNMT3A gene and characterised by overgrowth (increased height, head circumference and/or weight) in association with an intellectual disability. It is one of a family of overgrowth intellectual disability (OGID) syndromes.

It is inherited as an autosomal dominant condition which means that individuals with TBRS have a 50% chance of passing on the DNMT3A mutation and therefore TBRS to their children.