Heplotype gene linkage analysis for hemophilia A families
HUANG Rong1, CAO Ying1, ZHENG Tianjin2, ZHAO Shengke1, DOU Ruiyan1, HONG Shuzhen2, CHEN Jing3, LI Hongzhi1.
1.School of Life Science/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical University, Wenzhou, 325035; 2.Family Planning Publicity and Technical Guidance Station of Wenzhou City, Wenzhou, 325000; 3.Population and Family Planning Commission of Wenzhou City, Wenzhou, 325000
HUANG Rong,CAO Ying,ZHENG Tianjin, et al. Heplotype gene linkage analysis for hemophilia A families[J]. JOURNAL OF WEZHOU MEDICAL UNIVERSITY, 2016, 46(7): 482-489.
Objective: To develop variable number tandem repeat (VNTR) polymorphism, short tandem repeat (STR) polymorphism and restriction fragment length polymorphism (RFLP) heplotype gene linkage analysis for hemophilia A (HA) pedigrees in Wenzhou, further to provide evidences of gene prognosis of males and female carriers for HA genetic counseling and family planning guidance. Methods: For the HA probands and related family members, haplotype gene linkage analysis was processed. PCR was used to analyze the VNTR polymorphism in extragenic site DXS52 (St14) of clotting factor VIII (FVIII) gene, to analyze the STR polymorphism in extragenic sites DXS15 (CA)n, DXS9901 (GT)n, DXS1073 (GT)n and in intragenic sites intron 1 (GT)n, 13 (CA)n, 22 (GT)n (AG)n, 24 (GT)n of FVIII gene, and the STR polymorphism was identified by capillary electrophoresis. Also PCR/RFLP was used to analyze the RFLP in intragenic sites intron 18, 19 and 22 of FVIII gene. Results: The results of two HA pedigrees were taken as examples. In pedigree 1, the very young brother of proband was normal, the mother and grandmother of proband were carriers, the young aunt of proband was carrier and her very young son was normal. In pedigree 2, the grandmother of proband was not carrier, the X chromosome of proband was interited from his grandfather. Since the grandfather was not HA patient, supposing the most serious situation, it was deduced that a mutation of FVIII gene had happened to the X chromosome of the mother which interited from the grandfather when it was in germ cell of grandfather, thus the mother of proband was carrier. In pedigree 2, the very young sister of proband is carrier, and there will be risk for her sons, but the eldest aunt of proband and her very young daughter are not carriers. Conclusion: The VNTR-PCR, STR-PCR and PCR/RFLP haplotype gene linkage analysis of HA pedigrees of this study, especially the presymptomatic gene diagnosis of males, the gene diagnosis of female carriers without HA offspring, will have their very important clinical implications, can provide reliable evidences for genetic counseling and family planning guidance.
