Genetic Diagnosis and Prenatal Diagnosis of a Rare <scp>FVIII</scp> Family With Haemophilia A

It is very difficult to identify the genetic variation of haemophilia A. We examined a case report from a sizable, uncommon haemophilia family, analysing the application of DHPLC in the diagnosis of haemophilia A. The comprehensive clinical data and laboratory assessments of the proband within the family were meticulously compiled. Subsequent to this, tests were conducted to evaluate the activated partial prothrombin time (APTT) and the clotting activity of coagulation factor VIII (F VIII: C). Polymerase chain reaction (PCR) techniques were employed to identify any inversions within the F8 gene's introns 22 and 1. Thereafter, direct sequencing methodology was utilised to sequence all exons of the F8 gene. To analyse the copy number variations across all exons of the F8 gene, a multiple PCR combined with denaturing high-performance liquid chromatography (DHPLC) approach was adopted. In addition, specific pathogenic mutations predisposing to progenitor cell disorders were screened in family members. The APTT of the proband was 60 s. F VIII: C is < 1%. It was found that the progenitor F8 gene exon 14 had a 226 bp insertion sequence, which was of unknown origin and was a pathogenic mutation. The analysis combined with this family situation is consistent with the expectation. The mutation was used as the detection target to complete the prenatal diagnosis. The pathogenic mutation found in this family is a rare large fragment insertion mutation. It is necessary to combine multiple experimental methods to improve the success rate of genetic diagnosis of haemophilia A.