A large series of immunohistochemically confirmed cases of congenital muscular dystrophy seen over a period of one decade

Abstract

Although congenital muscular dystrophies (CMD) is a common condition among primary muscle disorders, there are only a few small series reported from India. AIMS, SETTINGS, AND DESIGN: Retrospective analysis to characterize histopathologically and/or immunohistochemically confirmed cases of CMD. Patients were identified retrospectively from the archived muscle biopsy reports between 1997 and 2007 at the Department of Neuropathology of the institute. Medical records were scrutinized for all details. There were 102 cases which were characterized by clinical phenotype and histopathology. Among these 56 had immunohistochemical staining and were included in the final analysis. Merosin staining performed in 53 samples identified nine patients with merosin negative CMD. The male to female ratio (M:F) was 2:1 and the mean age at presentation was 69.7 ± 62.2 months. All had grossly delayed motor milestones. There were 13 cases of Ullrich CMD confirmed by absent staining for collagen 6A1 in muscle. Mean age at diagnosis was 63.7 ± 27.9 months. Onset of symptoms was in infancy in 12 patients. All had significant delay in motor milestones and had classical features of proximal contractures, distal hyperextensibility, prominent calcaneum, velvety palms and soles with absent palmar creases. Mean creatine kinase (CK) value was 259.1 ± 109.4 IU/l. Alpha-dystroglycan (α-DG) deficiency was identified in three cases. Illness onset was in infancy. Classical magnetic resonance imaging (MRI) features were seen in all. Large group of 31 cases of merosin positive CMD had clinical findings of early onset limb weakness, hypotonia, and contractures; with histopathological evidence of dystrophy, and normal staining pattern of merosin, collagen 6A1 and α-DG. Mean age at evaluation was 58.61 ± 48.4 months. Majority (87.1%) had onset of symptom in infancy with delay in motor milestones. This study provides a significant data on one of the largest cohort of patients with CMDs from India. Immunohistochemistry (IHC) has definitely helped us to categorize 56 patients into specific subtypes of CMDs. This is essential for directing genetic analysis which is imperative for definitive diagnosis and also prenatal diagnosis.