METTL7A (methyltransferase like 7A), also known as AAM-B, is a 244 amino acid protein that is thought to function as a methyltransferase and is encoded by a gene which maps to chromosome 12. Encoding over 1,100 genes, chromosome 12 comprises nearly 4.5% of the human genome and is associated with a number of skeletal deformaties, including hypochondrogenesis, achondrogenesis and Kniest dysplasia. Chromosome 12 is also home to both a homeobox gene cluster which encodes crucial transcription factors for morphogenesis, and a natural killer complex gene cluster encoding C-type lectin proteins which mediate the NK cell response to MHC I interaction. Additionally, Trisomy 12p (three copies of the p arm of chromosome 12) leads to facial developmental defects, seizure disorders and a host of other symptoms varying in severity depending on the extent of mosaicism.