HDAC4 and 2q37 microdeletion syndrome: In humans, single-nucleotide polymorphisms (SNPs) in HDAC4 are associated with non-syndromic oral clefts [9], and haploinsufficiency of HDAC4 causes brachydactyly mental retardation syndrome (BDMR) [OMIM: 600430] with associated craniofacial abnormalities [10].