Gamma-carboxyglutamate excretion and calcinosis in juvenile dermatomyositis.
Proteins containing gamma-carboxyglutamic acid (Gla) are present in subcutaneous calcifications of adults with dermatomyositis or scleroderma. Sixteen children with juvenile dermatomyositis, including 7 with subcutaneous calcifications, were studied to determine if abnormal synthesis or turnover of Gla-containing proteins occurred. All study children had increased excretion of the amino acid that was greater than that of age- and sex-matched controls. Patients who had juvenile dermatomyositis with calcifications had a 3-fold increase in Gla excretion, and those without calcinosis had a 2-fold increase. Five other children with various connective tissue disorders and subcutaneous calcification had 2-fold increased Gla excretion. Decreased excretion of this amino acid was associated with salicylate therapy (80 mg/kg/24 hours). The data suggest an abnormal turnover of Gla-containing proteins in juvenile dermatomyositis. Metabolism of these proteins may be involved in the pathophysiology of soft-tissue calcification in children.
D015055:1-Carboxyglutamic Acid / Q000652:urine*; D000293:Adolescent; D000328:Adult; D000368:Aged; D001241:Aspirin / Q000627:therapeutic use; D002114:Calcinosis / Q000097:blood / Q000150:complications* / Q000652:urine; D002135:Calcium-Binding Proteins / Q000097:blood; D002648:Child; D002675:Child, Preschool; D003882:Dermatomyositis / Q000097:blood / Q000150:complications / Q000188:drug therapy / Q000652:urine*; D005260:Female; D005971:Glutamates / Q000652:urine*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin; D011516:Prothrombin / Q000097:blood
D002135:Calcium-Binding Proteins; D005971:Glutamates; D015675:Osteocalcin; D015055:1-Carboxyglutamic Acid; D011516:Prothrombin; D001241:Aspirin