Early elevation of factor IX level in japanese brothers with Haemophilia B Leyden who are carrying c. -35 g > a mutations in the promoter region of F9

Genotype-phenotype analyses of Iranian patients with hemophilia B (Leyden -) and hemophilia B (Leyden +): A single-center study

BACKGROUND

There is a high prevalence of inherited bleeding disorders in Iran, such as hemophilia A (HA) and hemophilia B (HB). This study aimed to analyze the molecular and clinical profiles of patients with HB.

METHODS

A single-center study was conducted among patients with severe HB between March 20, 2000, and June 31, 2023. The polymerase chain reaction (PCR) amplification was used for all of the major regions, such as the promoter, the exons, the adjacent intronic regions, and the untranslated regions of the F9 gene. Finally, Sanger sequencing was performed on the PCR products.

RESULTS

A total of 111 HB patients (17 with HB [Leyden +] and 94 with HB [Leyden -]) were enrolled in this study. Among 94 patients with HB (Leyden -), 59 (62.8 %) had missense, 21 (22.3 %) had nonsense, and 8 (8.5 %) had frameshift mutations. Moreover, the most frequent pathogenic variant in HB (Leyden +) was c.-17 A>G in this study.

CONCLUSION

The results of this study confirm that HB is caused by a wide range of molecular defects in Iran. Thus, by knowing the genotypes and phenotypes, we would be able to stratify the patients which is important in terms of their management and outcome.

Comprehensive approach to hemophilia

Hemophilia A, B are X-linked recessive bleeding disorder that typically results from a deficiency of clotting factor VIII (FVIII) and factor IX (FIX). The severity of the disease is determined according to the FVIII and FIX levels. Hemophilia A and B have similar symptoms and are both characterized by bleeding, particularly in large joints such as ankles, knees, elbows. Recurrent bleeding in joints eventually causes progressive hemophilic arthropathy. Life-threatening hemorrhages may occur rarely. Treatment of hemophilia has improved significantly in recent years with clotting factor concentrates. The average life expectancy was