日本人における血液凝固第Ⅷ因子遺伝子イントロン13内のVariable Number of Tandem Repeat(VNTR)

Abstract

Carrier detection and prenatal diagnosis of hemophilia A have been perfor- med accurately by restriction fragment length polymorphisms (RFLPs). However, a single intragenic DNA polymorphism with two (+ and -) alleles can be informative for no more than 50% of women and this approach is time-consuming. The dinucleotide repeat sequence of varying length known as (dC-dA)n ･ (dG-dT)n, hereafter designated (CA)n, within intron 13 of the factor Ⅷ gene was analyzed in Japanese subjects by the polymerase chain reaction (PCR). The investigation of this variable number of tandern repeat (VNTR) in 110 X chromosomes from 70 healthy subjects (30 males and 40 females) revealed five different allelic fragments, i. e. 20 (59.1%), 21 (23.7%), 22 (3.6%), 23 (11.8%) and 25 (1.8%) repeats. Nineteen (47.5%) out of the 40 females analyzed were heterozygous for this VNTR. These findings suggest a strategy for providing a highly informative marker available for factor Ⅷ gene tracking studies in hemophilia A kindreds in a quicker and easier way.