Myotonic Dystrophy Type 1


Abnormal expansions of the CTG repeat in the 3’UTR of the dystrophia myotonica-protein kinase (DMPK) gene on chromosome 19 (at 19q13.3) are associated with myotonic dystrophy type 1 (DM1). Analysis of the number of CTG trinucleotide repeats is routinely used in diagnostic and predictive testing of individuals symptomatic or at risk of DM1. The prevalence of DM1 is estimated to be 2-5 in 100,000 with approximately 1 in 3,500 cases being congenitally affected.

Testing at WRGL

Polymerase Chain Reaction (PCR) using a variety of primers is used to determine the number of CTG repeats in the DMPK gene or to indicate the presence of an expansion. The gene-specific PCR product can be visualised using fragment analysis on the 3130 Genetic Analyser. Results are compared with controls with known repeat sizes.
A small proportion of cases will require further testing which is not offered at WRGL and samples will be forwarded to another laboratory if additional testing is required/necessary.

Cost, Sample Requirements & Turnaround Times



Cost NZD*

Sample Requirements

Current TAT

DM1 TP-PCR $203 4 ml of whole blood in EDTA (purple top) 2 weeks
For urgent cases please contact the laboratory

*No direct charge for the central region DHBs covered by the Crown Funding Agreement




Myotonic Dystrophy type 1 (DM1) testing


Wellington Regional Genetics Laboratory (WRGL) provides a comprehensive, integrated diagnostic cytogenetic and molecular genetic testing service

btn find


(04) 918-5352