Nedavne pokroky v molekulovej diagnostike hemofilie položili zaklady pre študium genotypovych a fenotypovych suvislosti a študium vplyvu genovych mutacii na vyskyt komplikacii choroby, akymi su inhibitory FVIII. V praci prezentujeme prve vysledky Narodneho genetickeho hemofilickeho programu, založeneho v r. 2014. Geneticky sme doteraz vyšetrili 173 pacientov s hemofiliou A, z nich 141 s ťažkym stupňom hemofilie, čo predstavuje 60 % populacie ťažkych hemofilikov na Slovensku. V subore ťažkych hemofilikov sme identifikovali 39 roznych mutacii, z nich 18 novych, doposiaľ neevidovanych v medzinarodnej mutačnej databaze. Zastupenie mutacii v našej populacii 141 pacientov s ťažkym stupňom hemofilie je v zhode s literaturou, inverzie intronov 22 a 1 u 59 (42 %), nonsense mutacie u 16 (11 %), veľke delecie u 4 (3 %), frame shift/stop kodon mutacie u 38 (27 %), splice site mutacie u 5 (4 %) a missense mutacie u 19 (13 %) pacientov. Analyza genovych mutacii u 34 pacientov s inhibitormi potvrdila porovnateľne riziko vzniku inhibitora pri inverziach (27 %), nonsense mutaciach (25 %) aj pri frame shift/stop kodon mutaciach (29 %), pričom vyššie riziko inhibitorov nesu mutacie ľahkeho oproti mutaciam ťažkeho reťazca – OR:2,57(0,85–7,77). Hodnotenie efektu imunotolerančnej indukcie (ITI) u 22 pacientov (26 ITI kur) podľa typu mutacie ukazalo kompletnu a parcialnu remisiu v 75 % pri inverziach a v 88–100 % pri ostatnych genovych mutaciach. Vysledky su ovplyvnene malou početnosťou suboru, problematika si vyžaduje ďalšie študium.

Recent advances in molecular diagnosis of haemophilia have enabled the study of genotypic and phenotypic relationships and of the effect of gene mutations on the occurrence of serious disease complications, such as inhibitors. We present the first results of the National Genetic Haemophilia Program, established in 2014. So far, we have investigated 173 haemophilia A patients, of which 141 have severe haemophilia, representing 60% of the population of severe haemophiliacs in Slovakia. In severe haemophiliacs, we identified 39 different mutations, including 18 new mutations not yet listed in the international mutation database. The proportion of mutations in our population of 141 severe haemophiliacs is consistent with literature: inversions of introns 22 and 1 in 59 (42%), nonsense mutations in 16 (11%), large deletions in 4 (3%), frame shift/stop codon mutations in 38 (27%), splice site mutations in 5 (4%) and missense mutations in 19 (13%) of patients. Analysis of gene mutations in 34 inhibitor patients confirmed a comparable risk of inhibitor development in patients with inversions (27%), nonsense mutations (25%) and frame shift/stop codon mutations (29%), with a higher risk of mutations localized in parts of the F8 gene encoding the light chain of FVIII molecule compared to heavy chain mutations – OR: 2.57 (0.85-7.77). Evaluation of the success rate of immune tolerance induction (ITI) in 22 patients (26 ITI courses) according to the gene defects in inhibitor patients showed complete and partial remission in 75% and 88-100% of patients with inversions and other gene mutations, respectively. These results are influenced by the small number of patients and this issue requires further study.

Národné hemofilické centrum Kliniky hematológie a transfuziológie LF UK SZU Univerzitná nemocnica Bratislava Slovenská republika

Ústav lekárskej biológie genetiky a klinickej genetiky LF UK Univerzitná nemocnica Bratislava Slovenská republika

Mutations of the F8 gene in patients with severe haemophilia A and occurrence of FVIII inhibitors