Polymerase chain reaction in the detection of mRNA transcripts from the slow skeletal troponin T (TNNT1) gene in myotonic dystrophy and normal muscle

Recent studies have shown that the gene encoding for the slow skeletal troponin isoform T (TNNT1) is located on the proximal long arm of human chromosome 19 in the myotonic dystrophy (DM) region. In order to test TNNT1 as a candidate gene for DM, we have isolated TNNT1 cDNA from skeletal muscle from two healthy individuals and from two patients with DM. Sequencing of the TNNT1 cDNA from the DM and normal muscle revealed two sequence variants but no transcriptionally significant mutations. This work rules out a defect in the coding segment of TNNT1 as a cause of DM and provides a polymerase chain reaction protocol for studying troponin T gene expression.