PT - JOURNAL ARTICLE AU - Nelis, E AU - Timmerman, V AU - De Jonghe, P AU - Muylle, L AU - Martin, J J AU - Van Broeckhoven, C TI - Linkage and mutation analysis in an extended family with Charcot-Marie-Tooth disease type 1B. AID - 10.1136/jmg.31.10.811 DP - 1994 Oct 01 TA - Journal of Medical Genetics PG - 811--815 VI - 31 IP - 10 4099 - http://jmg.bmj.com/content/31/10/811.short 4100 - http://jmg.bmj.com/content/31/10/811.full SO - J Med Genet1994 Oct 01; 31 AB - Charcot-Marie-Tooth disease type 1 (CMT1) or hereditary motor and sensory neuropathy type I (HMSNI) is an autosomal dominant peripheral neuropathy. In most families the disease segregates with a 1.5 Mb duplication on chromosome 17p11.2 (CMT1A). A few patients have been found with point mutations in the PMP-22 gene. In some families linkage has been found with markers located on chromosome 1q21-q25 (CMT1B) and more recently mutations have been identified in the P0 gene. We analysed an extended CMT1 pedigree (CMT-B) without the CMT1A duplication. Significant positive linkage with chromosome 1 indicated that this family is of the CMT1B subtype. Sequencing of the candidate gene P0 located in chromosome band 1q21-q23 showed a C to A point mutation at position 446 in exon 3 resulting in an Asp134Glu substitution. Since the P0 mutation cosegregated with CMT1 disease we suggest that this mutation is the primary genetic cause of CMT1B in family CMT-B.