Double complex mutations involving F8 and FUNDC2 caused by distinct break-induced replication.
Genomic rearrangements are a well-recognized cause of genetic disease and can be formed by a variety of mechanisms. We report a complex rearrangement causing severe hemophilia A, identified and further characterized using a range of PCR-based methods, and confirmed using array-comparative genomic hybridization (array-CGH). This rearrangement consists of a 15.5-kb deletion/16-bp insertion located 0.6 kb from a 28.1-kb deletion/263-kb insertion at Xq28 and is one of the most complex rearrangements described at a DNA sequence level. We propose that the rearrangement was generated by distinct but linked cellular responses to double strand breakage, namely break-induced replication (BIR) and a novel model of break-induced serial replication slippage (SRS). The copy number of several genes is affected by this rearrangement, with deletion of part of the Factor VIII gene (F8, causing hemophilia A) and the FUNDC2 gene, and duplication of the TMEM185A, HSFX1, MAGEA9, and MAGEA11 genes. As the patient exhibits no clinically detectable phenotype other than hemophilia A, it appears that the biological effects of the other genes involved are not dosage-dependent. This investigation has provided novel insights into processes of DNA repair including BIR and the first description of SRS during repair in a pathological context.
Sheen
Campbell R
CR
Molecular Pathology Laboratory, Canterbury Health Laboratories, Christchurch, New Zealand. campbell.sheen@chmeds.ac.nz
Jewell
Ursula R
UR
Morris
Christine M
CM
Brennan
Stephen O
SO
Férec
Claude
C
George
Peter M
PM
Smith
Mark P
MP
Chen
Jian-Min
JM
D000293:Adolescent; D000951:Antigens, Neoplasm / Q000235:genetics; D001483:Base Sequence; D041321:Chromosomes, Human, X / Q000235:genetics*; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000235:genetics; D005169:Factor VIII / Q000235:genetics*; D020440:Gene Duplication; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000235:genetics; D006467:Hemophilia A / Q000235:genetics / Q000473:pathology; D006801:Humans; D008297:Male; D008957:Models, Genetic; D016254:Mutagenesis, Insertional; D009154:Mutation; D009363:Neoplasm Proteins / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics; D043562:Receptors, G-Protein-Coupled / Q000235:genetics; D017384:Sequence Deletion
D000951:Antigens, Neoplasm; D004268:DNA-Binding Proteins; C494708:HSFX1 protein, human; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; C110882:MAGEA11 protein, human; C520253:MAGEA9 protein, human; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D043562:Receptors, G-Protein-Coupled; C500606:TMEM185A protein, human; D005169:Factor VIII