The antithrombin III gene polymorphism in Japan: examination for haplotypes relevant to disordered antithrombin III biosynthesis.
In the human antithrombin III (AT III) gene of Caucasian, two restriction fragment length polymorphism (RFLPs) have been identified and used for the linkage analysis of many congenital AT III abnormality and deficiency. In the present study, we attempted to examine the existence and distribution of these RFLPs in Japanese and utilize them for the molecular survey of the members in the AT III Toyama kindred and 4 type Ia deficient families. An AT III cDNA clone was isolated by ourselves and served as a hybridization probe. In Japanese, the intragenic polymorphism, which is referred to + and - alleles, was evenly distributed (.49: .51), and the 5'-length polymorphism, designated as S and F alleles, was also conserved at a ratio of .4 to .6. However, the combined genotypes of both polymorphisms revealed disproportionate, and + and S, and - and F alleles seemed mainly to coexist. AT III genes of the AT III Toyama kindred showed the homozygous genotype of -/F, and all affected members of the deficient families demonstrated no distinguishable alterations on Southern blots, suggesting that a subtle defect in the AT III gene or the "trans-acting" disordered mechanism is responsible for the decreased AT III levels. According to some reports that a defective AT III gene is the cause of inherited AT III deficiency, it was implied that the abnormal AT III gene was located on the haplotype of -/F in 3 families and +/F in one. In two deficient families with heterozygous genotypes, the RFLPs were considered to bring a clue to determine the structural changes.
Oguma
Y
Y
Department of Clinical Laboratory Medicine, Toyama Medical and Pharmaceutical University School of Medicine, Japan.
Sakuragawa
N
N
Hiraga
K
K
D000483:Alleles; D000595:Amino Acid Sequence; D000990:Antithrombin III / Q000096:biosynthesis / Q000235:genetics*; D020152:Antithrombin III Deficiency; D001483:Base Sequence; D003001:Cloning, Molecular; D005260:Female; D005838:Genotype; D006239:Haplotypes; D000949:Histocompatibility Antigens Class II / Q000235:genetics*; D006801:Humans; D015151:Immunoblotting; D007564:Japan; D008297:Male; D008969:Molecular Sequence Data; D010375:Pedigree; D012150:Polymorphism, Restriction Fragment Length
D000949:Histocompatibility Antigens Class II; D000990:Antithrombin III