A novel mutation in exon b (R259C) of the MTM1 gene is associated with a mild myotubular myopathy. Mutation in brief no. 125. Online.
The genetic basis of the relatively mild myopathic symptoms exhibited in a male was investigated. Mutation screening of a candidate gene, MTM1, represented a chance of establishing the molecular defect and the mode of inheritance. SSCA detected variation of the exon b PCR products from the proband and his mother, compared to that observed upon analysis of the PCR products from other members of the family and 159 unrelated X chromosomes. Sequencing revealed a C775 to T transition, in the proband and his mother, but not in his unaffected brother. To confirm the presence of a base change in this region, a Cfol site was introduced into the PCR product of the wildtype allele by using the forward primer 5'-AGAAAATAAGACGGTCATTGcG-3' (mismatch base in small font) with the exon b reverse primer as used by Laporte et al (1996). Analysis of DNA from other members of the family using this method revealed that this is a new mutation in the proband's mother. This mutation would result in a Arg259->Cys substitution.
Donnelly
A
A
Centre for Medical Genetics, Department of Cytogenetics and Molecular Genetics, Women's and Children's Hospital, Adelaide, South Australia, 5006.
Haan
E
E
Manson
J
J
Mulley
J
J
D000483:Alleles; D019943:Amino Acid Substitution / Q000235:genetics; D001120:Arginine / Q000235:genetics; D003545:Cysteine / Q000235:genetics; D005091:Exons / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D009135:Muscular Diseases / Q000235:genetics*; D009154:Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction; D017027:Protein Tyrosine Phosphatases / Q000235:genetics*; D054558:Protein Tyrosine Phosphatases, Non-Receptor; D014960:X Chromosome / Q000235:genetics
D001120:Arginine; D017027:Protein Tyrosine Phosphatases; D054558:Protein Tyrosine Phosphatases, Non-Receptor; C099588:myotubularin; D003545:Cysteine