| Summary: | Spinal Muscular Atrophy (SMA) is a neuromuscular disorder characterized by the degeneration of alpha motor neurons in the anterior horn of the spinal cord, which leads to progressive weakness of the muscles.The majority of SMA cases (95%) are due to an autosomal recessive disorder caused by homozygous deletion and/or mutation of the alleles of the survival motor neuron 1 (SMN1) gene, causing deficiency in the survival motor neuron protein. A second set of genes, SMN2, is able to produce small amounts of the SMN protein. The number of available SMN2 gene copies and the extent of the expression of these genes modulate the severity of the disease. Nusinersen (Spinraza) has Health Canada's approval for the treatment of 5q SMA. Nusinersen is an antisense oligonucleotide that binds to the SMN2 pre-messenger ribonucleic acid, this leads to increasing the proportion of exon 7 in SMN2 messenger ribonucleic acid transcripts, which ultimately is translated into functional SMN protein. Nusinersen is administered via intrathecal injections of 12 mg in 5 mL solution at day 0, 14, 28, and 63, then given at four month intervals
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