Spinal muscular atrophy (SMA) is the second most prevalent autosomal recessive disorder, with a carrier frequency of approximately 1 in 40 to 50 individuals and an estimated occurrence of 1 in 10,000 live births. The majority of SMA cases are caused by the deletion of a portion of the SMN1 gene, which impairs the production of the essential SMN protein.
As a rare genetic condition, spinal muscular atrophy incidence is best described in terms of birth prevalence—that is, the number of children born with the disorder over a specific time frame. The classical forms of SMA arise from mutations in both copies of the SMN1 gene, located on chromosome 5, leading to a signi...
