Screening of intron 1 inversion and three intragenic factor VIII gene polymorphisms in Pakistani hemophilia A families

Application of Indirect Linkage Analysis for Carrier Detection of Hemophilia A in Kurdistan Region of Iraq: Usefulness of Intron 18 BclI T>A, Intron 19 HindIII C>T, and IVS7 nt27 G>A Markers

Hemophilia A (HA) is the most common congenital X-linked coagulopathy caused by mutations in the factor VIII gene. One in 5000 to 10 000 male persons worldwide suffer from HA. It is the archetype of high-cost, low-volume disease. Therefore, identification of carriers is crucial to avoid the birth of affected males. Tracking of the defective X chromosome through indirect linkage analysis represents the most practical method for screening for carriers in developing countries. In this study, 227 individuals from 41 families with HA and 100 normal participants were recruited from the Kurdistan region of Iraq and evaluated for intron 18 BclI, intron 19 HindIII, and IVS7 nt 27 markers by polymerase chain reaction restriction fragment length polymorphism and direct sequencing. Among the studied women, 49%, 42%, and 14% were discovered to be heterozygous for BclI, HindIII, and IVS7 markers, respectively. Using BclI, HindIII, and IVS7 markers, 56%, 46%, and 17% of the families were informative, respectively. The combined informativity of these polymorphic sites reaches 66%. The current study illustrates the effectiveness of the BclI and HindIII markers for the diagnosis of HA carriers among the Iraqi Kurdish population.

Evaluation of factor VIII polymorphic short tandem repeat markers in linkage analysis for carrier diagnosis of hemophilia A

Hemophilia A (HA) is the most common inherited X-linked recessive bleeding disorder caused by heterogeneous mutations in the factor VIII gene (FVIII). Diagnosis of the carrier is critical for preventing the birth of children affected by this coagulation disorder, which ultimately facilitates its management. Due to the heterogeneous nature of mutations, the large inversions and the complexity of the FVIII gene, direct recognition of the disease-associated mutation in HA is complex. Indirect linkage analysis using highly informative heterozygous polymorphic markers is an alternative method for determining the co-segregation of the mutant gene within a family for carrier detection of HA. The aim of the present study was to perform carrier diagnosis in a family with HA. Rapid multifluorescent polymerase chain reaction (PCR) was performed with six extragenic short tandem repeats (STRs), DXS1073, DXS15, DXS8091, DXS1227, DXS991, DXS993 and one intragenic marker, STR22 for linkage analysis in the HA family. All the STR markers employed in the present study were informative for linkages of pathogenic and healthy haplotypes among family members, particularly STR22, DXS1073 and DXS15. The STR marker, STR22, is within the FVIII gene while the DXS1073 and DXS15 markers are very close to the FVIII gene, where the chances of recombination are comparatively low, and provided the most accurate interpretation analysis, indicating that the proband's sister may have been the HA carrier. Rapid multifluorescent PCR using STR markers and linkage analysis was identified to be a simple method for performing HA carrier diagnosis.