Kaplan F, Kokotsis G, Capua A, Scriver C R
DeBelle Laboratory for Biochemical Genetics, McGill University, Montreal Children's Hospital Research Institute, Quebec.
Clin Invest Med. 1991 Aug;14(4):325-30.
Beta-thalassemia minor occurs at 5% frequency (on average) in populations migrant (since 1945) from Mediterranean countries to the province of Quebec. Individuals of Southeast Asian/Chinese and Asian Indian origin now living in the province also carry beta-thalassemia genes at similar frequencies. We characterized beta-thalassemia genes on 68 chromosomes (19 patients and 30 carriers identified by screening) to describe heterogeneity of beta-thalassemia alleles and to evaluate desirability of DNA tests in carrier screening. Thirteen different mutations account for 74% of the 68 beta-thalassemia chromosomes: seven occur on Mediterranean chromosomes (IVS I,nt110, Non 39, IVS I,nt6, IVS I,nt1G----A, IVS II,nt1, Fr8, IVS II,nt745) another three on SE Asian chromosomes (Fr 41-42, IVS II,nt654, HbE) and yet another three on Asian Indian chromosomes (IVS I,nt5, 619 bp del, IVS I,nt1G----T). Twenty-six percent (18/68) of the chromosomes carried none of 17 alleles accounting for 92-96% of beta-thalassemia molecular pathology in reference populations. The Italian beta-thalassemia chromosomes in the Quebec sample least resembled those in the corresponding source population. Until the spectrum of mutations in Quebec populations is fully defined, phenotype assay remains the most reliable and efficient method for beta-thalassemia carrier screening.
自1945年以来，从地中海国家移民到魁北克省的人群中，β地中海贫血轻型的发生率平均为5%。目前居住在该省的东南亚/华裔和亚洲印度裔个体也以相似的频率携带β地中海贫血基因。我们对68条染色体（通过筛查确定的19例患者和30名携带者）上的β地中海贫血基因进行了特征分析，以描述β地中海贫血等位基因的异质性，并评估DNA检测在携带者筛查中的适用性。13种不同的突变占68条β地中海贫血染色体的74%：7种发生在地中海染色体上（IVS I，nt110、非39、IVS I，nt6、IVS I，nt1G→A、IVS II，nt1、Fr8、IVS II，nt745），另外3种发生在东南亚染色体上（Fr 41-42、IVS II，nt654、HbE），还有3种发生在亚洲印度染色体上（IVS I，nt5、619 bp缺失、IVS I，nt1G→T）。26%（18/68）的染色体未携带17种等位基因中的任何一种，而这些等位基因在参考人群中占β地中海贫血分子病理学的92-96%。魁北克样本中的意大利β地中海贫血染色体与相应来源人群中的染色体最不相似。在魁北克人群中的突变谱完全确定之前，表型检测仍然是β地中海贫血携带者筛查最可靠、最有效的方法。
