To ascertain whether mood disorders, including bipolar and unipolar, are genetically associated with the monoamine oxidase A (MAOA) or monoamine oxidase B (MAOB) gene in the Chinese population, 132 cases of mood disorder and 88 normal controls were genotyped for the MAOA(CA)n, MAOB(GT)n, and MAOB(TG)n loci by the method of amplification fragment length polymorphism.
Among 132 cases with mood disorder, eight alleles (size: 112-126 bp) of locus MAOA(CA)n, 12 alleles (size: 168-198 bp) of locus MAOB(GT)n, and nine alleles (size: 195-213 bp) of locus MAOB(TG)n were observed.
In order to determine the possible role of the MAO region in susceptibility to affective disorders in an independent sample, we have genotyped 83 probands of bipolar affective disorder families, 56 sets of parents of bipolar probands, and 84 normal controls for intronic simple sequence repeat polymorphisms of the MAO-A and MAO-B genes.