Low α-N-acetylgalactosaminidase plasma concentration correlates with the presence and severity of the bipolar affective disorder.

Low α-N-acetylgalactosaminidase concentrations may cause the accumulation of some glycoproteins in the lysosomes in the brain during the gestational period, producing the clinical symptoms of BAD. α-N-acetylgalactosaminidase deficiency may not be the only cause of BAD, but it may be an important factor in the aetiology of this disease.