MacKenzie A E, MacLeod H L, Hunter A G, Korneluk R G
Division of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Canada.
Am J Hum Genet. 1989 Jan;44(1):140-7.
The gene for human apolipoprotein C2 (APOC2), situated on the proximal long arm of chromosome 19, is closely linked to the gene for the most common form of adult muscular dystrophy, myotonic dystrophy (DM). Six APOC2 RFLPs (TaqI, BglI, BanI, BamHI, NcoI, and AvaII) have been identified to date. We have conducted a comprehensive DM linkage study utilizing all six RFLPs and involving 50 families and 372 individuals. The most informative RFLPs are, in descending order, NcoI (lod = 6.64, theta = 0.05), BglI (lod = 6.12, theta = 0.05), AvaII (lod = 6.02, theta = 0.03), BanI (lod = 5.76, theta = 0.04), TaqI (lod = 4.29, theta = 0.06), and BamHI (lod = 1.75, theta = 0.01). A substantial increase in the lod scores over those seen with the individual RFLPs was obtained when the linkage of the entire APOC2 haplotype (composed of the six RFLPs) was studied (lod = 17.87, theta = 0.04). We have observed significant inter-APOC2 RFLP linkage disequilibrium. Consequently, the three most informative RFLPs have been found to be BanI, TaqI, and either BglI, AvaII, or NcoI polymorphisms. We also demonstrate linkage disequilibrium between DM and APOC2 in our French-Canadian population (standardized disequilibrium constant phi = .22, chi 2 = 5.12, df = 1, P less than 0.04). This represents the first evidence of linkage disequilibrium between APOC2 and the DM locus.
人类载脂蛋白C2（APOC2）基因位于19号染色体长臂近端，与最常见的成人肌营养不良症——强直性肌营养不良症（DM）的基因紧密连锁。迄今已鉴定出6种APOC2限制性片段长度多态性（RFLP）（TaqI、BglI、BanI、BamHI、NcoI和AvaII）。我们利用所有这6种RFLP进行了一项全面的DM连锁研究，涉及50个家系和372名个体。信息量最大的RFLP按降序排列依次为：NcoI（连锁对数 = 6.64，重组值 = 0.05）、BglI（连锁对数 = 6.12，重组值 = 0.05）、AvaII（连锁对数 = 6.02，重组值 = 0.03）、BanI（连锁对数 = 5.76，重组值 = 0.04）、TaqI（连锁对数 = 4.29，重组值 = 0.06）和BamHI（连锁对数 = 1.75，重组值 = 0.01）。当研究整个APOC2单倍型（由这6种RFLP组成）的连锁时，连锁对数比分立的RFLP观察值有显著增加（连锁对数 = 17.87，重组值 = 0.04）。我们观察到APOC2各RFLP之间存在显著的连锁不平衡。因此，已发现信息量最大的3种RFLP为BanI、TaqI以及BglI、AvaII或NcoI多态性。我们还在我们的法裔加拿大人群中证明了DM与APOC2之间存在连锁不平衡（标准化不平衡常数phi = 0.22，卡方 = 5.12，自由度 = 1，P < 0.04）。这是APOC2与DM基因座之间存在连锁不平衡的首个证据。
