The early detection of dystrophia myotonica

THE disease, dystrophia myotonica, is thought to result from a single gene of varying expressivity, as a result of modification perhaps by environmental factors, or perhaps by one or more other genes (Penrose, 1948; Lynas, 1957). The clinical signs of the disease involve many different systems, including skeletal muscles with a specific pattern of weakness, wasting and myotonia, the brain with mental deterioration, and the lens with zoned white punctate and iridescent opacities (Vogt, 1931) or posterior subcapsular opacities (Fleischer, 1916, 1917, 1918), as well as gonadal atrophy and frontal balding. In addition, investigations reveal abnormalities of various systems including skull radiographic changes (DiChiro and Caughey, 1960), pathological abnormalities of the central nervous system (Rosman and Rebeiz, 1967) and of the peripheral nervous system (Allen, Johnson and Woolf, 1969), electrocardiographic abnormalities (Evans, 1944; Spillane, 1951), high fasting serum insulin levels and hypersecretion of insulin in response to a glucose load (Huff, Horton and Lebovitz, 1967; Huff and Lebovitz, 1969), and low serum levels of immunoglobulin G due to an increased rate of catabolism (Zinneman and Rotstein