Blood Group, Dombrock System, also known as dombrock blood group system, is related to optic atrophy with or without deafness, ophthalmoplegia, myopathy, ataxia, and neuropathy and autosomal dominant optic atrophy. An important gene associated with Blood Group, Dombrock System is ART4 (ADP-Ribosyltransferase 4 (Inactive) (Dombrock Blood Group)).