Wei J, Hemmings G P
Institute of Biological Psychiatry, Schizophrenia Society of Great Britain, Bangor, Gwynedd, UK.
Psychiatr Genet. 1999 Dec;9(4):177-81. doi: 10.1097/00041444-199912000-00002.
Two X-linked microsatellites, (AC) n repeats at the monoamine oxidase (MAO)-A locus and (TG)n repeats at the MAO-B locus, were studied in 140 unrelated Caucasian male patients with schizophrenia and 91 unrelated Caucasian male controls. Among these subjects, we totally typed out nine alleles for the (AC) n repeats and eight alleles for the (TG) n repeats by using a PCR-based procedure. Allelic frequencies of either (AC) n repeats or (TG) n repeats were not found to be significantly different between patients and controls. However, a significant excess of the (AC)18/(TG)23 haplotype with a relative risk of 4.05 (95%; CI 1.15-14.26) was observed in patients with schizophrenia (Fisher's P = 0.011). The coefficient of linkage disequilibrium (delta) for the (AC)18/(TG)23 haplotype was 0.019 in schizophrenic patients and -0.046 in control subjects, respectively. The latter reached statistical significance (chi 2 = 6.02; df = 1; P < 0.02). The present findings suggest that linkage disequilibrium between polymorphic loci for human MAO-A and MAO-B may be associated with schizophrenia, and the (AC)18/(TG)23 haplotype may render an individual more vulnerable to such an illness.
在140名无亲缘关系的患有精神分裂症的白种男性患者和91名无亲缘关系的白种男性对照中，研究了两个X连锁微卫星，即单胺氧化酶（MAO）-A基因座处的（AC）n重复序列和MAO-B基因座处的（TG）n重复序列。在这些受试者中，我们通过基于聚合酶链反应（PCR）的方法总共鉴定出（AC）n重复序列的9个等位基因和（TG）n重复序列的8个等位基因。未发现患者和对照之间（AC）n重复序列或（TG）n重复序列的等位基因频率存在显著差异。然而，在精神分裂症患者中观察到（AC）18/（TG）23单倍型显著过量，相对风险为4.05（95%置信区间：1.15 - 14.26）（Fisher检验P = 0.011）。（AC）18/（TG）23单倍型的连锁不平衡系数（δ）在精神分裂症患者中为0.019，在对照受试者中为 -0.046。后者具有统计学意义（卡方 = 6.02；自由度 = 1；P < 0.02）。目前的研究结果表明，人类MAO-A和MAO-B基因多态性位点之间的连锁不平衡可能与精神分裂症有关，并且（AC）18/（TG）23单倍型可能使个体更容易患这种疾病。
