Mutation in the nerve-specific 5'non-coding region of Cx32 gene and absence of specific mRNA in a CMTX1 Italian family. Mutations in brief no. 195. Online.
Charcot-Marie-Tooth type I demyelinating neuropathies are genetically heterogeneous disorders (chrmosome 17,1,X). There are at least three genes on X chromosome, the more frequently involved being Cx32 in Xq13.1. Cx32 encodes for connexin-32, a gap junction protein of 283 aminoacids. We report the results of molecular studies in a CMTX1 Italian family, in which the mutation, found in the 5'-UTR, resulted in an abnormal mRNA connexin-32 expression. Mutations in PMP22 and P0 genes were also excluded in this family. Cx32 gene analysis carried out by PCR-SSCP on family members genomic DNAs, running a 321 bp fragment spanning the TATA box, the trasciptional start site, and the non coding exon 1b, revealed a shift correlated with a transition from C to T at position 40 of exon 1b of the 12 affected members, while was not found in the controls. Then the RT PCR-SSCP on cDNA from two peripheral nerve biopsies of two heterozygous females of the family were sequenced showing only the wild-type alleles and suggesting that mutated mRNAs were too unstable to be detected. The result also suggests a regulating role of the 5'-UTR of Cx32 mRNA.
Flagiello
L
L
Istituto Internazionale di Genetica e Biofisica, CNR, Via Marconi 10, 80125 Napoli, Italy.
Cirigliano
V
V
Strazzullo
M
M
Cappa
V
V
Ciccodicola
A
A
D'Esposito
M
M
Torrente
I
I
Werner
R
R
Di Iorio
G
G
Rinaldi
M
M
Dallapiccola
A
A
Forabosco
A
A
Ventruto
V
V
D'Urso
M
M
D020121:5' Untranslated Regions / Q000235:genetics*; D002607:Charcot-Marie-Tooth Disease / Q000235:genetics*; D017630:Connexins / Q000235:genetics*; D005260:Female; D006801:Humans; D009154:Mutation / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics*; D014960:X Chromosome / Q000235:genetics*; D000097002:Gap Junction beta-1 Protein
D020121:5' Untranslated Regions; D017630:Connexins; D012333:RNA, Messenger; D000097002:Gap Junction beta-1 Protein