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.

A study of morphometric and histopathological features of muscle biopsies from patients of myopathy.

The aim of this study is to analyse the morphological pattern of different types of myopathies including morphometric data. The cases were diagnosed as myopathy on the basis of clinical details, EMG findings, serum CK values. Muscle biopsies were performed and hematoxylin & eosin stain and Masson's trichrome stain were done. Muscle fiber diameters were measured using an eye piece micrometer of 100 fibers in each biopsy, these values were plotted and histograms were constructed. From this, mean fiber diameter (MFD), standard Deviation (SD), atrophy factor (AF), hypertrophy factor (HF) and variability coefficient (VC) were calculated. Degree of inflammation was scored semiquantitatively and presence of degenerating fibers, regenerating fibers, perifascicular atrophy, perivascular lymphocytic infiltration and vasculitis were noted. Out of 25 patients, 9 patients of inflammatory myopathy were adults, of the 16 patients of dystrophy 9 patients were adults. Along with weakness of limbs, skin rash was seen in 2 patients of dermatomyositis. Degree of inflammation was more in the patients of inflammatory myopathy than in the patients of dystrophy. Necrotic and regenerating fibers were seen in both groups. Perifascicular atrophy was seen in 1 case of dermatomyositis. Atrophy factor was higher in cases of dystrophy and so was hypertrophy factor. Variability coefficient >250 was found on 90% of dystrophy cases and it was <250 in the cases of inflammatory myopathy. Morphometry provides valuable data, which helps in distinguishing dystrophy from cases of myopathy with inflammation.

Analysis of dystrophin gene deletions by multiplex PCR in eastern India.

The most common genetic neuromuscular disease of childhood, Duchenne and Becker muscular dystrophy (DMD/BMD) is caused by deletion, duplication or point mutation of the dystrophin gene located at Xp 21.2. In the present study DNA from seventy unrelated patients clinically diagnosed as having DMD/BMD referred from different parts of West Bengal, a few other states and Bangladesh are analyzed using the multiplex polymerase chain reaction (m-PCR) to screen for exon deletions and its distribution within the dystrophin gene. Out of seventy patients forty six (63%) showed large intragenic deletion in the dystrophin gene. About 79% of these deletions are located in the hot spot region i.e, between exon 42 to 53. This is the first report of frequency and distribution of deletion in dystrophin gene in eastern Indian DMD/BMD population.