Letters to the Editor

Indian Pediatrics 2004; 41:290-291

Duchenne Muscular Dystrophy in Monozygotic Twins

Duchenne muscular dystrophy (DMD), an X-linked disorder, is a rare occurrence in monozygotic twins, previously reported on five occasions(1-5). We report a rare case of DMD in a pair of monozygotic twins confirmed by DNA analysis for both monozygosity and mutation in the dystrophin gene.

Five-year-old twin boys were admitted to our hospital with history of progressive difficulty in walking, climbing stairs and frequent falls. There was delay in the attainment of motor milestones. Both boys had bilateral calf muscle hypertrophy with weakness of proximal muscles of lower and upper limbs. Serum creatinine kinase levels were grossly elevated (>11,000 IU/L) in both boys, and muscle biopsy showed dystrophic changes. DNA analysis for mutation detection in the dystrophin gene revealed intragenic deletion of exons 45-48 in both children. The monozygosity was confirmed by DNA analysis. Mother’s CPK level was within normal limits. Four generation pedigree revealed no other involved member in the family suggesting that the deletion in the dystrophin gene represented a new mutation.

The rare occurrence of such a genetic disorder in monozygotic twins gives us an opportunity to study to what extent genetic and environmental factors control the different manifestations of the disease.

M. L. Kulkarni,
K.S. Keshavamurthy,
Department of Pediatrics,
J.J.M. Medical College,
Davangere-577004,
Karnataka, India.

 

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