Six molecular patterns leading to hemophilia A phenotype in 18 females from Poland

Authors: Janczar, S, Babol-Pokora, K, Jatczak-Pawlik, I, Taha, J, Klukowska, A, Laguna, P, Windyga, J, Odnoczko, E, Zdziarska, J, Iwaniec, T, Koltan, A, Jamrozik, M, Ruranska, I, Janczar, K, Szczepanski, T, Pietrys, D, Balwierz, W, Trelinski, J, and Mlynarski, W.

Publication: Thromb.Res.; 193,9-14. June 2020

Affiliations: Department of Pediatrics, Oncology and Hematology, Medical University of Lodz, Poland; Department of Pediatrics, Hematology and Oncology, Warsaw Medical University, Poland; Institute of Hematology and Transfusion Medicine in Warsaw, Poland; Department of Hematology, Jagiellonian University, Krakow, Poland; Department of Pediatrics, Hematology and Oncology, Nicolaus Copernicus University in Torun, Collegium Medicum in Bydgoszcz, Poland; Department of Hematology and Bone Marrow Transplantation, Medical University of Silesia, Katowice, Poland; Department of Pediatric Hematology and Oncology, Zabrze, Medical University of Silesia, Katowice, Poland; Department of Pathology, Medical University of Lodz, Poland ; Department of Pediatric Oncology and Hematology, University Childrens’ Hospital of Krakow, Poland; Institute of Pediatrics, Jagiellonian University – Medical College, Krakow, Poland ; Department of Hemostasis, Medical University of Lodz, Poland.

Abstract: INTRODUCTION: Female hemophilia is an intriguing rare disorder and few larger reports on its genetic etiology are available. While historically the diagnosis was satisfactorily reached by factor VIII activity assays, the clinical and potentially therapeutic heterogeneity of female hemophilia calls for comprehensive molecular diagnosis in each case. Currently, the genetic investigations are not a part of routine, state-funded, diagnostics in Poland, and thus molecular epidemiological data are missing. AIM: We set out to perform a comprehensive genetic analysis of Polish females with hemophilia A. PATIENTS/METHODS: Eighteen females with hemophilia A (including 2 with severe and 5 with moderate hemophilia phenotype) consented for genetic diagnostics. To establish F8 mutations, we used next-generation sequencing of a panel of genes associated with hematological disorders, standard assays for recurrent intragenic F8 inversions and MLPA when deletions were suspected. When appropriate we also used karyotyping, genomic microarrays and X chromosome inactivation assays. RESULTS: While abnormally skewed X-chromosome inactivation combined with a F8 variant on the active allele was, as expected, the most common genetic etiology, a number of other genetic scenarios were unraveled. This included: misdiagnosis (molecular diagnosis of vWd), Turner syndrome, compound heterozygosity and androgen insensitivity syndrome (a phenotypical 46,XY female with a novel androgen receptor gene mutation). We report 3 novel F8 mutations. CONCLUSION: Every case of female hemophilia warrants full genomic diagnostics, as this may change the diagnosis or reveal broader morbidity than a coagulation disorder (Turner syndrome, androgen insensitivity, or cardiovascular morbidity that we described previously in a SHAM syndrome carrier).