CSAD is a 493 amino acid protein that exists as a homodimer and belongs to the group II decarboxylase family. CSAD catalyzes the conversion of 3-sulfino-L-alanine to hypotaurine and carbon dioxide, binds pyridoxal phosphate as a cofactor and undergoes alternative splicing to produce three isoforms. The gene encoding CSAD maps to human chromosome 12, which encodes over 1,100 genes and comprises approximately 4.5% of the human genome. Chromosome 12 is associated with a variety of diseases and afflictions, including hypochondrogenesis, achondrogenesis, Kniest dysplasia, Noonan syndrome and trisomy 12p, which causes facial developmental defects and seizure disorders.