[Duchenne muscular dystrophy carrier presenting with mosaic X chromosome constitution and muscular symptoms--with analysis of the barr bodies in the muscle]

Abstract

A 53-year-old female with muscular symptoms and incomplete Turner's syndrome was presented. She had two sons with Duchenne type muscular dystrophy (DMD). Her muscular symptoms became apparent at age 52 years, and her elevated serum CK, EMG and pathological findings of the biopsied muscle were consistent with muscular dystrophy. Her cytogenetic analysis from the cultured lymphocytes and fibroblasts showed a 45XO/46XX/47XXX chromosome constitution. Analysis of number of Barr bodies in the muscle specimen revealed that the total number of the bodies were significantly decreased in this case than in the control muscles. The result indicated that nuclei of 45XO karyotype were evidently present in her muscle and contributed to the process of muscle fiber breakdown as a major pathogenetic factor. However, inactivation of normal X chromosome also concerned the pathologic process because there were nuclei with Barr bodies in the damaged fibers as well. Only seven cases with X chromosome mosaicism and muscular symptoms attributable to DMD gene were seen in the literature. Four of them showed rather typical clinical features of DMD, but the muscular symptoms were much milder in the remainder, and patients were still able to walk in their middle lives. It was presumed that the severity of the clinical symptoms was parallel to the ratio of 45XO karyotype in the total number of muscular nuclei.