Recombination breakpoints in the Charcot-Marie-Tooth 1A repeat sequence in Norwegian families.
OBJECTIVE
To investigate the recombination breakpoint in a 3.2 kb junction fragment of the 24 kb CMT1A repeat sequences (CMT1A-REPs) on chromosome 17p11.2-12.


METHODS
Thirty-eight Norwegian CMT1 patients and 15 asymptomatic family members of 15 separate families including 10 normal controls were investigated using repeat (REP)-PCR.


RESULTS
Twenty-six (68.4%) of the CMT1 patients from 9 (60%) families were positive for the CMT1A duplication which was not found in any of the controls. In 89.9% of the REP-PCR positive families the recombination breakpoint was mapped to a 1.7 kb "hot-spot" region, and in 11.1% of the families to a 1.5 kb region telomeric to the 1.7 kb region.


CONCLUSIONS
The frequency and regions for CMT1A-REPs crossover events in Norwegian CMT1A cases are similar to what is found in other populations. REP-PCR is not, however, as sensitive as other diagnostic methods to detect the CMT1A duplication.
Aarskog
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NK
Department of Neurology and Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, University of Bergen, N-5021 Bergen, Norway. Nina.Aarskog@Haukeland.no
Vedeler
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CA
D002607:Charcot-Marie-Tooth Disease / Q000235:genetics*; D006801:Humans; D009664:Norway; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic / Q000235:genetics*; D020079:Terminal Repeat Sequences / Q000235:genetics*