Background: Hemophilia A is a X-linked hereditary bleeding disorder. According to mutation, decrease in FVIII level cause severe to mild phenotype. Development of FVIII inhibitor is the most feared complication of treatment.

Aims: We evaluated our Hemophilia-A patients’ mutations, factor levels and inhibitor status.

Methods: The data of 48 boys with Hemophilia A treated at Uludag University Pediatric Hematology Department were retrospectively screened. Patients’ factor levels and inhibitor status were recorded and compared with FVIII mutation type.

Results: Thirty-nine out of 48 patients were severe Hemophilia A; 4 moderate and 5 mild Hemophilia A. In severe Hemophilia A group; intron 22 inversion (n: 24), inversion 1(n:1), missense (n:3), nonsense (n:3), frame shift (n:3), deletion (n:5) mutations were detected. In moderate Hemophilia A group; 2 missense mutation were detected. In the rest (n:2) mutation analayses still continuing and MLPA test was planned. All of the mild Hemophilia A patients (n:5) had missense mutation. We found 3 novel missense mutations among our cases.
Of 48 patients, 8 (16.6%) had FVIII inhibitor. One of them had mild hemophilia A, inhibitor level was low responsive and became negative within one year. The remaining 7 patients had severe Hemophilia A (4 intron 22, 3 large deletion). Of the four cases with intron 22, two were siblings. In the other, there was no additional risk factor except intron 22. The remaining 3 patients with inhibitor had severe hemophilia with large deletion and they were close relatives.

Conclusions: In our study, the most common mutation was intron 22 inversion as noted in the literature. Only 4 (16.6%) of these cases had inhibitor. Three other patients with severe hemophilia A with inhibitor had large deletion. Three novel missense mutations found.

« Back to ISTH 2020 Congress

ISTH Congress Abstracts - https://abstracts.isth.org/abstract/fviii-gene-mutation-analysis-and-evaluation-of-clinical-data-one-center-result/