Carrier frequency of Spino-muscular atrophy in individuals of a reproductive age group from North India

Introduction: Spinal muscular atrophy (SMA) is a neuro-muscular disorder caused by biallelic variations in Survival Motor Neuron 1 gene (SMN1) located on chromosome 5q13.2. It is the most common hereditary cause of neonatal death. Ethnicity specific studies are desirable for estimating the prevalence of carrier status of this disease in a population. Objectives: To estimate the carrier frequency of SMA among individuals of a reproductive age group in a North Indian cohort. Methods: SMA carrier screening was offered to individuals of a reproductive age group (>18 years) visiting a tertiary care center. Multiplex ligation-dependent probe amplification (MLPA) and quantitative real-time polymerase chain reaction (PCR) were the molecular techniques used to detect the carrier status. Results: A total of 198 individuals without a family history of SMA were screened in this study. The carrier frequency of heterozygous deletion of SMN1 gene in our cohort was found to be 1 in 30 (~3/100). Conclusion: The carrier frequency of SMA is high in our country. The data from the study emphasize the need of a population carrier screening program on SMA in India.