X-linked Charcot-Marie-Tooth (CMT) neuropathies (CMTX1, CMTX2, CMTX3) show different clinical phenotype and molecular genetics

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · American Journal of Human Genetics

OSTI ID:134227

Ionasescu, V V; Searby, C C; Ionasescu, R ^[1]

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1. Univ. of Iowa Hospitals and Clinics, Iowa City, IA (United States)

The purpose of this study was to compare the X-linked dominant type CMTX1 (20 families) with X-linked recessive types CMTX2 and CMTX3 (2 families). The clinical phenotype was consistent with CMT peripheral neuropathy in all cases including distal weakness, atrophy and sensory loss, pes cavus and areflexia. Additional clinicial involvement of the central nervous system was present in one family with CMTX2 (mental retardation) and one family with CMTX3 (spastic paraparesis). Tight genetic linkage to Xq13.1 was present in 20 families with CMTX1 (Z=34.07 at {theta}=0) for the marker DXS453. Fifteen of the CMTX1 families showed point mutations of the connexin 32 coding region (5 nonsense mutations, 8 missense mutations, 2 deletions). Five CMTX1 neuropathy families showed no evidence of point mutations of the CX32 coding sequence. These findings suggest that the CMTX1 neuropathy genotype in these families may be the result of promoter mutations, 3{prime}-untranslated region mutations or exon/intron splice site mutations or a mutation with a different type of connexin but which has close structural similarities to CX32. No mutations of the CX32 coding region were found in the CMTX2 or CMTX3 families. Linkage to Xq13.1 was excluded in both families. Genetic linkage to Xp22.2 was present in the CMTX2 family (Z=3.54 at {theta}=0) for the markers DXS987 and DXS999. Suggestion of linkage to Xq26 (Z=1.81 at {theta}=0) for the marker DXS86 was present in the CMTX3 family.

• OSTI ID: 134227
• Report Number(s): CONF-941009--
• Journal Information: American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
BIOLOGICAL MARKERS
EXONS
GENE MUTATIONS
GENES
GENETIC MAPPING
GENETICS
GENOTYPE
HEREDITARY DISEASES
HUMAN X CHROMOSOME
INTRONS
MENTAL DISORDERS
NERVOUS SYSTEM DISEASES
PATIENTS
PHENOTYPE
SPLICING
STATISTICS