UBE2A encodes a member of the E2 ubiquitin-conjugating enzyme family that is required for post-replicative DNA damage repair and may play a role in transcriptional regulation; its loss-of-function is causative of “UBE2A deficiency syndrome” or “X-linked Nascimento-type intellectual disability syndrome” (#300860). This evidence concerns the gene UBE2S and syndromic X-linked intellectual disability Nascimento type.