Characterisation of two novel large F8 deletions in patients with severe haemophilia A and factor VIII inhibitors.

TY - JOUR

T1 - Characterisation of two novel large F8 deletions in patients with severe haemophilia A and factor VIII inhibitors.

AU - Roth, Lukas

AU - Marschalek, Rolf

AU - Oldenburg, Johannes

AU - Oyen, Florian

AU - Schneppenheim, Reinhard

PY - 2011

Y1 - 2011

N2 - Large deletions are found in approximately 5% of patients with severe haemophilia A, but only a few deletion breakpoints have been characterised precisely so far. In this study we characterised the deletion breakpoints of two patients with severe haemophilia A, large deletions and factor VIII (FVIII) inhibitors, and subsequently established deletion-specific assays for the identification of carriers. Patient 1 had a deletion of 37,410 bp comprising exon 1 and the F8 promoter region, and a 5 bp homology (GGGCC) is present at the chromosomal fusion site. In patient 2, a deletion of 22,230 bp including parts of intron 25, exon 26 and 3'-UTR was identified. No homologous repetitive elements were found at the breakpoints. However, both breakpoints were located within long terminal repeats of endogenous retroviruses and the DNA motif TTTAAA - known to be able to bend DNA molecules - was identified at the centromeric breakpoint. By deletion-specific PCR experiments we were able to identify a heterozygous state in mother 2 (carrier) while mother 1 presented only with wild-type alleles (non-carrier). Both deletions are most likely created by DNA double strand breaks and subsequent DNA repair by the non-homologous end joining DNA repair pathway (NHEJ). The exact identification of the deletion breakpoints provides a reliable diagnostic tool for carrier identification in affected families by means of a deletion-specific PCR.

AB - Large deletions are found in approximately 5% of patients with severe haemophilia A, but only a few deletion breakpoints have been characterised precisely so far. In this study we characterised the deletion breakpoints of two patients with severe haemophilia A, large deletions and factor VIII (FVIII) inhibitors, and subsequently established deletion-specific assays for the identification of carriers. Patient 1 had a deletion of 37,410 bp comprising exon 1 and the F8 promoter region, and a 5 bp homology (GGGCC) is present at the chromosomal fusion site. In patient 2, a deletion of 22,230 bp including parts of intron 25, exon 26 and 3'-UTR was identified. No homologous repetitive elements were found at the breakpoints. However, both breakpoints were located within long terminal repeats of endogenous retroviruses and the DNA motif TTTAAA - known to be able to bend DNA molecules - was identified at the centromeric breakpoint. By deletion-specific PCR experiments we were able to identify a heterozygous state in mother 2 (carrier) while mother 1 presented only with wild-type alleles (non-carrier). Both deletions are most likely created by DNA double strand breaks and subsequent DNA repair by the non-homologous end joining DNA repair pathway (NHEJ). The exact identification of the deletion breakpoints provides a reliable diagnostic tool for carrier identification in affected families by means of a deletion-specific PCR.

M3 - SCORING: Journal article

VL - 105

SP - 279

EP - 284

JO - THROMB HAEMOSTASIS

JF - THROMB HAEMOSTASIS

SN - 0340-6245

IS - 2

M1 - 2

ER -