Letters to the Editor

Indian Pediatrics 2002; 39:980-981

Duchenne Muscular Dystrophy in a Female Child

This is with reference to the article published in Indian Pediatrics titled "Duchenne Muscular Dystrophy in a female child"(1). However, the diagnostic work up is rather incomplete. Whether a DNA analysis was performed and what did the immunocytochemistry of the muscle biopsy show are important to make a diagnosis of the type of muscular dystrophy(2). The muscle immunocytochemistry is regularly being performed at NIMHANS and the DNA for Duchenne muscular dystrophy at Centre for Cellular and molecular Biology, Hyderabad. We should utilize the expertise of such institutions in order to make a final diagnosis.

In the present case, the clinical picture and the family history of both sexes being affected suggests a diagnosis of Severe Childhood Autosomal Recessive Muscular Dystrophy (SCARMD), rather than Duchenne Muscular dystrophy.

SCARMD is a rapidly progressive disease particularly predominant in North Africa and Tunisia(3). The age of onset ranges from 3 to 12 years. The clinical severity varies and three groups are identified-one with onset between 3 to 8 years and loss of ambulation between 10 to 15 years, a second onset between 4 to 9 years with loss of ambulation between 15 to 20 years, and a third with onset between 4 to 12 years and loss of ambulation between 20 to 30 years(4). Molecular genetic studies showed normal expression of dystrophin but selective loss of 50 KD dystrophin associated glycoprotein (50 DAG)(5). The French group identified the same problem amongst Europeans and called the protein Adhalin(6).

Linkage studies have shown that some of the SCARMD families with 50 DAG deficiency may localize to 13q although there may be additional genes which are responsible for causing the deficiency of 50 DAG(7). It is also interesting to note that cardiac involvement is not a usual feature of SCARMD. It is difficult to prognosticate in this disease and needs to depend on the individual case. As the condition is usually inherited through an autosomal recessive mechanism both parents are heterozygote carriers and there is a 25% risk of any further child being similarly affected.

Our experience and that of our friends in Bombay suggests that the SCARMD in India appear not to have deficiency of alpha sarcoglycan (adhalin) as seen in the Europeans but in beta or gamma sarcoglycan. We have too few cases to arrive at a conclusion at one center and therefore this requires a cooperative effort to establish the facts. We in MDA India, a parent support group, have been dealing with children with muscular dystrophy for sometime now and would certainly be happy to interact with anyone wanting to pursue research into muscular dystrophies.

References

REFERENCES

1. Joshi S. Duchenne muscular dystrophy in a female child. Indian Pediatr 2002; 39: 98.

2. Sewery CA, Dubowitz V. Histochemical and immunocytochemical studies in neuromuscular diseases. In: Walton, JN Karpati, G. eds, Disorders of Voluntary Muscle. Edinburgh Churchill Livingstone, 1994, pp. 261-318.

3. Ben Hamida M, Fardeu M, Attia N. Severe childhood muscular dystrophy affecting both sexes and frequent in Tunisia. Muscle Nerve 1983; 6: 469-480.

4. Dubowitz V. Muscle Disorders in Childhood. W.B. Saunders Company. 2nd edition. 1995; 82-90.

5. Roberds SL, Anderson RD, Ibranghimov-Beskrovnaya, O Campbell KP. Primary structure and muscle-specific expression of the 50 kDa dystrophin-associated glycoprotein (adhalin). J Biol Chem 1993; 268, 23739-23742.

6. Fardeau M, Matsumara K, Tome FMS, Collin H, Lecturcq F, Kaplan JC, et al. Deficiency of the 50 kDa dystrophin associated glycoprotein (adhalin) in severe childhood autosomal recessive muscular dystrophy in children native from European countries. Coptes Rendus de i’ Academie des Sciences, Sciences de la vie. 1993, 316: 799-804.

7. Bushby KMD. Diagnostic criteria for the limb girdle muscular dystrophies: report of the ENMC consortium on limb girdle muscular dystrophies. Neuromusc Disord 1995; 5: 71-74.