Association analysis between mood disorder and monoamine oxidase gene

To ascertain whether mood disorders, including bipolar and unipolar, are ge netically associated with the monoamine oxidase A (MAOA) or monoamine oxida se 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 MAO A(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. Comparison of the alle le frequency of the three loci showed no difference between mood disorder c ases and normal controls on average. When each group was stratified into se veral subgroups, significant differences were found. On the MAOA(CA)n locus , the frequency of 116 bp allele was higher in the female bipolar disorder cases (0.2581) compared with that in the female unipolar disorder patients (0.1154) (Z=2.15, p<0.05). On the MAOB(GT)n locus,the frequency of 180 bp a llele was higher in bipolar disorder patients (0.1579) than that in normal controls (0.0678) (Z=2.05, p<0.05). The frequency of this allele was even h igher in female bipolar disorder patients (0.1719) than that in female norm al controls (0.0541). On the MAOB(TG)n locus, the frequency of 205 bp allel e was higher in female bipolar disorder patients (0.6406) than that in fema le normal controls (0.4375) (Z=2.17, p<0.05). For the unipolar disorder pat ients, the frequency of this allele was higher in female cases (0.5222) tha n that in male cases (0.1818) (Z=3.49, p<0.05). As far association studies, significant association between bipolar disorder and MAOB gene was detecte d. For the 180 bp allele of MAOB(GT)n, the relative risk (RR) of biploar ve rsus normal control was 2.58 (p<0.05), and the RR of female bipolar disorde r versus female normal control was 3.63 (p<0.05). For the 205 bp allele of MAOB(TG)n, the RR of female bipolar disorder versus female normal control w as 2.29 (p<0.05). An. J. Med. Genet. (Neuropsychiatr, Genet.) 96:12-14, 200 0. (C) 2000 Wiley-Liss, Inc.