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Factor IX gene haplotypes in Brazilian Blacks and characterization of unusual Ddel alleles
Author(s) -
Figueiredo M. S.,
Bowen D. J,
Silva W. A.,
Zago M. A.
Publication year - 1994
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1994.tb06739.x
Subject(s) - taqi , genetics , haplotype , biology , allele , population , haemophilia a , bamhi , allele frequency , gene , polymorphism (computer science) , restriction enzyme , haemophilia , medicine , environmental health
Summary Analysis of factor IX gene polymorphisms is considered the best approach for prenatal diagnosis and carrier detection of haemophilia B when the identification of the gene mutation is not possible. Studies involving factor IX gene polymorphisms in Black populations are scarce and essentially restricted to the North‐American Black population whose composition is substantially different from that of the Brazilian and presumably other Black populations of South America. In this paper we report the analysis of eight factor IX gene polymorphisms in Brazilian Blacks: 5’ BamHI, DdeI, intron 2 BamHI, XmnI, TaqI, MspI, MnII and HhaI. Characterization of the VNTR‐like Ddel polymorphism revealed six different alleles: B, AB, A 2 B, A 2 B 2 , A 3 B and A 5 , the last being described here for the first time. The 5’ BamHI, DdeI, MspI and Hhal polymorphisms showed the highest heterozygosities (0.40‐0.50) and are in linkage equilibrium with one another. 19 complete haplotypes could be identified in this population. Based on the results we propose a systematic strategy for carrier detection and prenatal diagnosis of haemophilia B in this population. The combined analysis of four polymorphisms (5’ BamHI, HhaI, MspI and DdeI) provided an informative genetic marker in 85% of the females. The use of all eight polymorphisms allows information in 95% of females. Additionally, differences in gene frequencies and haplotype distribution suggest dissimilarities in factor IX gene polymorphisms between the Brazilian and the North‐American Black populations.