Genetic and Clinical Profile of Patients of Duchenne Muscular Dystrophy: Experience from a Tertiary Care Center in Eastern India.

Objectives: To study the genetic pattern, clinical profile and to find any correlation between them in patients of Duchenne muscular dystrophy. Methods: Patients were selected from Neurogenetic clinic on the basis of clinical features, elevated serum CPK level and electromyographic features. After history and clinical examination, molecular genetic testing was performed by Polymerase Chain Reaction (PCR) technique. Results: Among 100 patients, 73 patients had genetically confirmed disease while 8 cases were proven by biopsy, and thus a total 81 cases were further taken up for the study. Mean age of onset of clinical symptoms was 3.9 yrs; Valley sign and calf hypertrophy were most consistent features, while about 51% had facial weakness. Out of 73 genetically confirmed cases 53 (72.6%) showed deletion in distal exons and 12 (16.4%) showed deletion in both proximal and distal exons while 8 (10.9%) had only proximal deletion. There was no correlation between genetic pattern and clinical features. Conclusion: The positivity of PCR- based diagnosis is higher in our study possibly related to highly selective group of patients. Phenotype and genotype correlation was not seen.

Deletional mutations of dystrophin gene and carrier detection in eastern India.

Objective. To determine the pattern of deletions of the dystrophin gene, the major class of mutations among the Duchenne and Becker muscular dystrophy patients of eastern India and to analyze the carrier frequency of the female members of the proband’s family. Methods. Deletional mutations occurring in patients have been characterized by multiplex polymerase chain reaction. Carrier state of mothers and sisters of probands were analyzed by either of two methods: 1) typing polymorphic short tandem repeat markers in or around the regions of deletion, by radioactive polymerase chain reaction and 2) quantitative real time amplification of the region of deletion. Results. Deletions were detected in 67 (62.04%) out of 108 male patients, about 76.12% of these being localized in the central hot spot region of the gene, i.e., between exon 42 to exon 53 and 17.91% at the proximal hot spot i.e., between exon 1 to exon 20. In the present study were found 43 types of deletions, out of which 25 (58%) were new deletions, which were not described earlier among the Indian patients. Distribution pattern of deletions in different hot spot regions has been compared with that of other countries and statistical analysis reveals significant difference between countries (p<0.001). Correlation of the pattern of deletion with clinical phenotype of patients has been discussed. Interesting case of germline mosaicism and its implications in counseling has also been discussed. Conclusion. About half the mothers of affected probands were not carriers of the deletion, underscoring the need to use real time techniques for carrier detection.