[Abnormal calcium metabolism in myotonic dystrophy: increased level of serum 1,25(OH)2D concentration and augmented intestinal calcium absorption].
Myotonic dystrophy (MyD) is a multisystemic disorder characterized by muscle weakness, myotonia, cataract and frontal baldness. Several endocrinological abnormalities are also known in this disorder. Although presence of bone changes, such as hyperostosis, has been frequently reported in MyD patients, there have been few published papers in which calcium metabolism was precisely examined. The present study was designed to elucidate the possibility of the presence of abnormal calcium metabolism in MyD by using the oral calcium tolerance test. Ten patients with MyD, 11 patients with other neuromuscular disorders (non-MyD) and 9 healthy control subjects were investigated according to the method of Broadus et al. Increments of serum and urinary calcium levels after oral calcium load (1 gram) were determined as indices of intestinal calcium absorption. There were no significant differences in basal plasma calcium and phosphate levels among the three groups. Plasma 1,25(OH)2D level in MyD (38.0 +/- 11.8 pg/ml, Mean +/- SD) was significantly higher than those in the other two groups (normal subjects 21.8 +/- 7.0; P less than 0.01, non-MyD 21.8 +/- 12.0; P less than 0.01), respectively. In contrast, plasma 25(OH)D and 24, 25(OH)2D levels were not significantly different among these groups. Fasting urinary calcium excretion in both MyD (0.151 +/- 0.069 mg/100 ml GF) and non-MyD (0.141 +/- 0.077) was significantly higher than that in normal subjects (0.064 +/- 0.048). Calcemic response in MyD (1.08 +/- 0.20 mg/dl) was significantly increased when compared with that in normal subjects (0.72 +/- 0.34, P less than 0.02) and non-MyD (0.54 +/- 0.31, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
D000328:Adult; D002117:Calcitriol / Q000097:blood*; D002118:Calcium / Q000378:metabolism* / Q000652:urine; D005260:Female; D006801:Humans; D007408:Intestinal Absorption; D008297:Male; D008875:Middle Aged; D009223:Myotonic Dystrophy / Q000378:metabolism*; D010710:Phosphates / Q000097:blood
D010710:Phosphates; D002117:Calcitriol; D002118:Calcium