OBJECTIVE: To describe the clinical and molecular genetic findings in 2 carriers of Duchenne muscular dystrophy (DMD) who exhibited marked hemiatrophy. Duchenne muscular dystrophy is an X-linked disorder in which affected male patients harbor mutations in the dystrophin gene. Female patients with heterozygous mutations may be manifesting carriers.
DESIGN: Case study.
SETTING: Neurology clinic.
PATIENTS: Two manifesting carriers of DMD.
INTERVENTIONS: Clinical and radiologic examinations along with histologic and molecular investigations.
RESULTS: Both patients had marked right-sided hemiatrophy on examination with radiologic evidence of muscle atrophy and fatty replacement on the affected side. In each case, histologic analysis revealed a reduction in dystrophin staining on the right side. Genetic analysis of the dystrophin gene revealed a tandem exonic duplication in patient 1 and a multiexonic deletion in patient 2 with no further point mutations identified on the other chromosome.
CONCLUSIONS: Marked hemiatrophy can occur in DMD manifesting carriers. This is likely to result from a combination of skewed X-inactivation and somatic mosaicism.