BACKGROUND: Factor VIII intron 22 inversions (Inv22) cause 40%-45% of severe cases of hemophilia A in all human populations. Currently, Inv22 can be analyzed either by Southern blotting or by rapid long-distance-PCR-based approaches. We describe an alternative method using inverse-PCR (I-PCR). METHODS: I-PCR involved 3 steps: (a) BclI restriction; (b) self-ligation of restriction fragments, providing BclI rings; and (c) standard multiplex-PCR analysis. PCR was achieved by use of a set of 3 primers that yielded a 487-bp amplicon for the nonrearranged intragenic allele and a 559-bp amplicon for the Inv22 allele. Specific primer sites were targeted by masking relevant regions for human repeats and low-complexity DNA. Inv22 I-PCR was applied to samples from 16 individuals (8 women and 8 men) representing 24 X chromosomes previously genotyped by Southern blotting. Additionally, we evaluated the sensitivity and the ability to assess eventual Inv22 carrier mosaicisms by experiments using artificial DNA mixtures (Inv22 + no-Inv22 male samples). RESULTS: Results for previously genotyped samples agreed with results of Southern blot analyses. As expected, cell composition of the artificial mosaic was linearly reflected by the relative intensities of Inv22 signals. I-PCR was estimated to detect Inv22-positive cells at concentrations as low as approximately 5%. CONCLUSION: The proposed technique provides a rapid tool for Inv22 genotyping.
BACKGROUND: Factor VIII intron 22 inversions (Inv22) cause 40%-45% of severe cases of hemophilia A in all human populations. Currently, Inv22 can be analyzed either by Southern blotting or by rapid long-distance-PCR-based approaches. We describe an alternative method using inverse-PCR (I-PCR). METHODS: I-PCR involved 3 steps: (a) BclI restriction; (b) self-ligation of restriction fragments, providing BclI rings; and (c) standard multiplex-PCR analysis. PCR was achieved by use of a set of 3 primers that yielded a 487-bp amplicon for the nonrearranged intragenic allele and a 559-bp amplicon for the Inv22 allele. Specific primer sites were targeted by masking relevant regions for human repeats and low-complexity DNA. Inv22 I-PCR was applied to samples from 16 individuals (8 women and 8 men) representing 24 X chromosomes previously genotyped by Southern blotting. Additionally, we evaluated the sensitivity and the ability to assess eventual Inv22 carrier mosaicisms by experiments using artificial DNA mixtures (Inv22 + no-Inv22 male samples). RESULTS: Results for previously genotyped samples agreed with results of Southern blot analyses. As expected, cell composition of the artificial mosaic was linearly reflected by the relative intensities of Inv22 signals. I-PCR was estimated to detect Inv22-positive cells at concentrations as low as approximately 5%. CONCLUSION: The proposed technique provides a rapid tool for Inv22 genotyping.
Authors: Steve Keeney; Tony Cumming; P Vincent Jenkins; James S O'Donnell; Michael J Nash Journal: Eur J Hum Genet Date: 2011-06-08 Impact factor: 4.246
Authors: Kevin R Viel; Afshin Ameri; Thomas C Abshire; Rathi V Iyer; Raymond G Watts; Charles Lutcher; Cynthia Channell; Shelley A Cole; Karl M Fernstrom; Shelley Nakaya; Carol K Kasper; Arthur R Thompson; Laura Almasy; Tom E Howard Journal: N Engl J Med Date: 2009-04-16 Impact factor: 91.245
Authors: Liliana C Rossetti; Claudia P Radic; Miguel M Abelleyro; Irene B Larripa; Carlos D De Brasi Journal: Int J Mol Sci Date: 2011-10-24 Impact factor: 5.923