A study of the recombination hotspot and polymorphisms of Charcot Marie Tooth disease type 1A in Chinese patients

Objective: To study the recombination hotspot and polymorphisms of distal REP at position 3795 of Charcot.Marie.Tooth disease type 1A（CMT1A） in Chinese patients. Methods: Polymerase chain reaction combined with restriction enzyme digestion and analysis of Short Tandem Repeat（STR） sequence were used to detect gene duplications on chromosome 17p11.2-12 in 30 CMT1 patients.Whether a 1.7kb region was the recombination hotspot was determined by the detecting rate of novel junction fragments in duplication patients. Polymorphisms was identified by restriction analysis of PCR products. Results: A hotspot was observed through the detection of novel junction fragments in 70% of 21 unrelated CMT1A patients. The polymorphisms of distal REP at position 3795 was 63.8%. Conclusion: The crossover breakpoints of most Chinese CMT1A patients occurs in a 1.7kb region which is the recombination hotspot. The novel junction fragments can be used as screening method to diagnose CMT1A duplications clinically