CHARCOT-MARIE-TOOTH NEUROPATHIES - FROM CLINICAL DESCRIPTION TO MOLECULAR-GENETICS

Ninety-five families with Charcot-Marie-Tooth (CMT) neuropathies were studied clinically, electrophysiologically (MNCVs and EMGs), and by mo lecular genetics. Fifty-four families (56.8%) were type 1A mapped at 1 7p11.2-p12 and DNA duplication was present in 50 (92.6% of CMT1A famil ies). One family with type 1B (1.1%) mapped at 1q22-q23 showed a point mutation of the myelin Po gene. Eighteen families (18.9%) were type C MT2 based on electrophysiological studies. Molecular genetics was not yet conclusive. Twenty CMT families were with X-linked dominant inheri tance (CMTX1) (21.1%) mapped at Xq13.1 and connexin 32 (CX32) point mu tations were present in 15 families (75%) (five nonsense mutations, ei ght missense mutations, two deletions). Two CMI families (2.1%) with X -linked recessive inheritance showed no point mutations of CX32 and th eir mapping was different from CMTX1, respectively at Xp22.2 for CMTX2 and at Xq26 for CMTX3. (C) 1995 John Wiley & Sons, Inc.