Molecular evaluation in infantile spinal muscular atrophy

Introduction: Infantile Spinal Muscular Atrophy (infantile SMA) is a neurodegenerative disease caused primarily by the deletion of the SMN1 gene at 5q11.1 - 13.3. Its severity ranges from type I, in early childhood, to type IV. Objectives: To describe molecular findings in patients with SMA, who were nationally referred to the Institute of Neurology and Neurosurgery and to describe the frequency per 100,000 people in each province of the island. Patients and Methods: 105 patients, referred between 1997 and 2011, were studied. The polymerase chain reaction (PCR) technique was used to detect the deletions of exons 7 and 8 of the SMN1 gene, and DraI and DdeI enzymes, in 2% agarose gel, were used for digestion. Results: 59% of the patients were diagnosed with SMA I, 28.6 % with SMA II and 12.4 % with SMA III. 36.2% of total patients presented deletions of exons 7, 8, 35.2% only deletion of exon 7 and 28.2 % did not present deletion of exons. Conclusion: These results are discussed according to the international literature. The frequency per 100,000 inhabitants in each province is presented and discussed according to ancestral diversity of the Cuban population. Also, the originality of the study is mentioned as it is the first report of this type in a Caribbean population.