[Insulin resistance and clinical evolution in infantile myotonic dystrophy].

We present the results of a 13 year follow-up of seventeen children with myotonic dystrophy, with the aim of better understanding the progression of this disease. We want to emphasize two basic aspects; first, the detection of myotonia with the use of EMG during the first five years of life when the clinical profile is suggestive of the disease, previous reports have stated that this sign appears relatively late in the disease process, and secondly, we want to point out that more than 50% of these patients showed insulin-resistance starting from the sixth year of life. This aspect of the disease has been well described in adult patients, but is practically absent in the pediatric literature. Hyperinsulinemic subjects demonstrated an intellectual quotient significantly lower than those subjects with normal insulin levels (p < 0.01). Basal insulin levels also had a predictive value in relation to the rest of the points n the insulin curve. The changes in insulin resistance are discussed in relation to cellular membrane changes present in myotonic dystrophy.