NONRADIOACTIVE DETECTION OF 17P11.2-DUPLICATION IN CMT1A - A STUDY OF78 PATIENTS

Charcot-Marie-Tooth disease type 1 (CMT1) is a peripheral neuropathy c haracterised by progressive distal muscular atrophy and sensory loss w ith markedly decreased nerve conduction velocity, mostly inherited as an autosomal dominant trait. The most common form, type 1A, is associa ted with a 1.5 Mb DNA duplication in region p11.2-p12 of chromosome 17 in many patients. In this study a non-radioactive test for detection of the CMT1A duplication based on an RM11-GT microsatellite polymorphi sm is presented. Although different methods have been devised for this purpose, the present method has the advantage of being rapid, informa tive, economical, easily interpretable, and, therefore, it represents a very useful tool for diagnosis of CMT1A, especially before clear man ifestation of clinical symptoms. Seventy-eight patients diagnosed clin ically as having CMT and evaluated by electrophysiological methods wer e tested with an RM11-GT microsatellite and with probe pVAW409R3. The CMT1A duplication was found in 76% of the 56 unrelated patients. RM11- GT was the most informative marker with a heterozygosity of 89%.