Goldman A, Krause A, Ramsay M, Jenkins T
Department of Human Genetics, School of Pathology, South African Institute for Medical Research, Johannesburg.
Am J Hum Genet. 1996 Aug;59(2):445-52.
A high prevalence of myotonic dystrophy (DM) has been described in South African Caucasoid Afrikaans-speaking families in the northern Transvaal. Evidence is presented for a strong founder effect, with a single haplotype occurring on 68% of all Caucasoid DM chromosomes; among the Afrikaans speakers, the proportion was 83%. In addition to this major haplotype, five minor DM haplotypes in the Caucasoids and two minor haplotypes in DM individuals of mixed ancestry were found. All DM chromosomes, however, had a common haplotype core, namely, Alu (ins), HinfI-2 (intron 9), and TaqI-2 (D19S463). We have detected significant linkage disequilibrium between the DM mutation and particular alleles of the extragenic markers D19S112 and D19S207. Significant differences were found in allele and haplotype distributions in the Caucasoid DM and non-DM chromosomes and Negroid non-DM chromosomes. These findings together with the strong association of allele 3 at the D19S63 locus on 93% (14/15) of the South African DM chromosomes suggest that the majority of present-day DM mutations in South African Caucasoids may have originated from a common initial founder who introduced one of the European ancestral mutations.
在南非德兰士瓦省北部讲南非荷兰语的白种人家庭中，强直性肌营养不良（DM）的患病率很高。有证据表明存在强烈的奠基者效应，在所有白种人DM染色体中，68%出现单一单倍型；在讲南非荷兰语的人群中，这一比例为83%。除了这种主要单倍型外，在白种人中还发现了5种次要的DM单倍型，在混血DM个体中发现了2种次要单倍型。然而，所有DM染色体都有一个共同的单倍型核心，即Alu（插入）、HinfI - 2（内含子9）和TaqI - 2（D19S463）。我们检测到DM突变与基因外标记D19S112和D19S207的特定等位基因之间存在显著的连锁不平衡。在白种人DM和非DM染色体以及黑人非DM染色体的等位基因和单倍型分布中发现了显著差异。这些发现以及在93%（14/15）的南非DM染色体上D19S63位点的3号等位基因的强烈关联表明，南非白种人中目前大多数DM突变可能起源于一个共同的初始奠基者，他引入了一种欧洲祖先突变。
