Spinal muscular atrophy (SMA) is the result of being born without - or with a defective version of - the survival motor neuron 1 (SMN1) gene. This gene helps humans produce the survival motor neuron (SMN) protein. Insufficient amounts of this protein prevent the nerve cells in the spinal cord from developing properly. As a result, this rather rare disease is still the number one cause of genetic-related death in infants.

ISIS Pharmaceuticals, in partnership with Biogen Idec, is developing a treatment for SMA Type I that will help infants manufacture SMN protein by manipulating the splicing of the SMN2 gene. SMN2 is a biological backup of the SMN1 gene. The amount of copies of SMN2 on the child's genome will determine the severity of the disease. Infants with SMA Type I, the most severe form, have only one or two copies of this important fallback gene. This new medication, known as ISIS-SMN Rx, is an antisense drug, which means that its molecular structure includes mRNA that can affect the translation of DNA into proteins.

Darryl C. De Vivo, MD Contracted Research: ISIS Pharmaceuticals