Myotonic dystrophy in Otago, New Zealand

To determine the prevalence of myotonic dystrophy (DM) in Otago, the ethnic distribution of the disease, any founder effect, the complications and adequacy of health care, and the quality of life of sufferers in this region.

DM patients were identified through hospital records and assessed using a structured questionnaire, neurological examination, and review of hospital records. Quality of life was evaluated using the SF-36 Health Survey, and compared to patients with other neuromuscular conditions and New Zealand norms.

21 patients were identified, giving a prevalence of 11.6 per 100,000. All were of European descent. There was no evidence of a common ancestor. Not all patients had had essential investigations such as electrocardiogram and many had not been seen by the genetic service. DM patients had higher scores on the bodily pain subscale of the SF-36 Health Survey, compared to neuromuscular controls and the general population. Subjects differed significantly from New Zealand norms on four of the eight subscales.

DM is relatively common in Europeans in Otago, but we found no cases in other ethnic groups. The disease affects aspects of quality of life, and management could be improved by use of a clinical care pathway.