F8 intron 22 inversions and SNP rs73563631 in unrelated families with severe haemophilia A: clinical features and gene testing implications

MIGUEL M. ABELLEYRO; LILIANA C. ROSSETTI; MARIA DE LOS ANGELES CURTO; CLAUDIA P. RADIC; VANINA D. MARCHIONE; CARLOS D. DE BRASI

THROMBOSIS AND HAEMOSTASIS

SCHATTAUER GMBH-VERLAG MEDIZIN NATURWISSENSCHAFTEN

Lugar: Stuttgart ; Año: 2015 vol. 115 p. 678 - 681

0340-6245

F8 intron 22 inversions (INV22), the commonest cause of severe haemophilia A (HA), are mostly represented by type I (INV22-1) and type II (INV22-2) patterns (4:1) using BclI-fragments´ based techniques such as inverse shifting-PCR (IS-PCR/2008). Using IS-PCR/2008, we identified unusual patterns of the INV22-1 and INV22-2 (characterised by no signals in the diagnostic test and conventional INV22-1/-2 patterns in the complementary test) in patients and carriers from two (0.6%) out of 308 Argentinean families with severe-HA. A theoretical analysis of the 85 SNPs embedded in the relevant BclI-fragments followed by PCR-BclI-RFLP analysis allowed identification of the SNP rs73563631*G allele associated with a new BclI-restriction site in all four patients of Family 1 and 2. Linkage analysis using seven F8-linked-STRs in the two families confirmed two unrelated haplotypes in phase with INV22-1/-2. Screening of 404 X-chromosomes from the Argentinean general population failed to detected SNP rs73563631*G allele (q