类孟买型在两个近亲与随机婚配家系中的遗传特点

To Study on Genetic Characteristic for the Para-Bombay Phenotype of Genetic Characteristic in Two Families that Stochastic Marriage and Intermarriage

目的调查分析近亲与随机婚配的两个家系成员个体间的类孟买型分布状态，了解类孟买表现型在该两家系中的遗传特点。方法以血型血清学试验作为检测基础，用PCR—SSP法进行ABO基因分型，扩增FUT1，FUT2基因，对PCR扩增产物进行直接测序或分子克隆测序后，分别鉴定两家系成员的类孟买表现型。结果近亲婚配的家系1中，先证者与其兄、弟均从父母中得到了FUT1基因的547548住两碱基AG缺失（h1），880-881住两个T碱基缺失的突变点（h2），表现为h1，h2类孟买型；父亲为^2基因携带者；母亲与先证者的女儿均为^1基因携带者。随机婚配的家系2中先证者与兄弟姐妹共4人，只有先证者本人的两条单倍体均遗传了父、母亲的FUT1基因的547-548位两碱基AG缺失（hi），表现为h1h1类孟买型；其他兄弟姐妹与父亲、母亲、先证者的儿子均为h1基因携带者，血型为正常的表现型。两家系成员的FUT2住点均为正常的野生型。近亲婚配家系Ⅰ中hh纯合子遗传发生率为100％；随机婚配家系Ⅱ中M纯合子遗传发生率为25％。结论该两个家系调查发现，类孟买表现型的遗传方式符合常染色体隐性遗传规律，近亲婚配比随机婚配可大大增加类孟买表现型的遗传概率。

Objective To investigate and study on distribution for the para-Bombay phenotype in two families that stochastic marriage and intermarriage. To understand the para-Bombay phenotype of genetic characteristics in two families. Methods Two prophetic families were performed by serologic tests and PCR-SSP based ABO genotyping. FUTland FUT2gene sequences were analyzed with direct sequencing or cloning sequencing of PCR amplified products for identify the para-Bombay phenotype. Results The first ancestry was a internuptial family. The para-Bombay phenotype of proband and his two siblings had inherited FUTlgene with one AG deletion at nucleotide position547-548（hl）and another genotype mu-tation with two of the three T repeats deletion at nucleotides 880-881 （h2）from their parent. Three siblings were repre-sented h1,h2 phenotype. The father was carrier of the h2 gene. The mother and the proband＇s daughter were carrier of the h1 gene. The second ancestry was a stochastic marriage. The para-Bombay phenotype of proband had inherited a homozy-gous of the FUT1gene with AG deletion at nucleotide position 547-548 from parent and represented h1h1 phenotype. But her folk were carrier of the h1 gene and their blood group were familiar type. No mutation at FUT 2 gene or ABO gene was detected in the two families. The inherited probability of the homozygous hh gene was 100% in the internuptial family. But the inherited probability of the homozygous hh gene was 25 % in the stochastic marriage family. Conclusion Para-Bombay phenotype abides by the rule of recessive inheritance. The inherited probability of para-Bombay phenotype is increaser in the internuptial family than stochastic marriage family.