Intron 22‐specific long PCR for the Xba I polymorphism in the factor VIII gene

Abstract

Summary. The Xba I polymorphic site in the factor VIII gene is present in the int22h-1 region which is found in two other copies (int22h-2 and int22h-3) distal to the gene. Previously the polymorphic status of the Xba I locus was studied by either Southern blot or PCR that amplified all three copies. Here we report the use of a long PCR that specifically amplifies the intragenic site in intron 22, making use of this marker an easy and reliable assay. Moreover, about 25% of previously uninformative Turkish haemophilia A families examined with three markers proved to be informative for linkage analysis, using the Xba I polymorphism.

Combined analysis of the MspI and XbaI polymorphisms in intron 22 of the factor VIII gene for detection of hemophilia A in a Korean population

“…In the present study, the expected heterozygosity rate for the XbaI/int22h-1 polymorphism in the Korean population was 43.6%, a value similar to the 48% heterozygosity rate in the Caucasian population (El-Maarri et al, 1999). The value for the XbaI/int22h-1 polymorphism in the Korean population was much higher than the value (20%) for the BclI/intron 18 polymorphism in this same population (Choi et al, 2000).…”

“…Because of these difficulties, the use of the XbaI/int22h-1 polymorphism has been restricted to the clinical diagnosis of hemophilia A. However, El-Maarri et al (1999) developed a PCR-based analysis method that is specific for the XbaI/int22h-1 polymorphism. When El-Maarri et al (1999) used this method to analyze the DNA of Turkish patients, they reported that XbaI/int22h-1 polymorphism analysis was effective for 60% of families who were uninformative with other intragenic markers.…”

“…However, El-Maarri et al (1999) developed a PCR-based analysis method that is specific for the XbaI/int22h-1 polymorphism. When El-Maarri et al (1999) used this method to analyze the DNA of Turkish patients, they reported that XbaI/int22h-1 polymorphism analysis was effective for 60% of families who were uninformative with other intragenic markers. In subsequent studies, XbaI/int22h-1 polymorphism was reported to have a heterozygosity rate of 48-50%, which did not vary for different ethnic groups (Wion et al, 1986;Chan et al, 1989;Peake et al, 1993).…”

“…The extragenic homologous sequences, int22h2-2 and int22h-3, also have polymorphic sites for XbaI and MspI (Chan et al, 1989;Naylor et al, 1995;Bowen et al, 2000). Thus, detection of XbaI/int22h-1 and MspI/int22h-1 polymorphisms at the three polymorphic sites of int22h would require efficient amplification of those specific sequences (De Brasi et al, 1999;El-Maarri et al, 1999).…”

Eighteen Years of Molecular Genotyping the Hemophilia Inversion Hotspot: From Southern Blot to Inverse Shifting-PCR

“…Notably, the contemporary reports of El-Maari et al . (1999) [29] and De Brasi et al . [30] both described methods based on hemispecific LD-PCR for Xba I RFLP genotyping, one primer targeting single copy DNA on F8 intron 22 and the second primer targeting int22h repeat sequence.…”