Survival of motor neuron 2 gene (SMN2)

The **Survival of motor neuron 2 gene (SMN2)** is a human protein-coding gene located near its paralog SMN1 on chromosome 5q13. SMN2 and SMN1 encode identical proteins, essential for spliceosome assembly and multiple core cellular processes such as mRNA processing, transcriptional regulation, and cytoskeleton maintenance[3][5]. Unlike SMN1, a critical single nucleotide change in SMN2 causes most of its mRNA transcripts to exclude exon 7, resulting in production of nonfunctional or unstable SMN protein[2][4]. The number of SMN2 gene copies inversely correlates with the severity of spinal muscular atrophy (SMA), making SMN2 a major therapeutic target for this disease, through strategies that increase production of full-length SMN protein[2][4][5]. SMN2 is involved in cellular housekeeping functions in both the nucleus and cytoplasm; it is not associated with disease when lost alone (i.e., with a normal SMN1), but modifies disease severity when SMN1 is absent[1][5]. Therapies for SMA include splicing modulators (e.g., nusinersen, risdiplam), gene therapy (onasemnogene abeparvovec), and epigenetic drugs including certain HDAC inhibitors shown preclinically to upregulate SMN2 expression[2]. **Note:** - SMN2 is a valid therapeutic target, but is best described as a *protein-coding gene/disease modifier* rather than a classic receptor, enzyme, or transporter. - The target name and description do not need adjustment for spelling, coverage, or relevance; SMN2 is a correctly identified therapeutic target in the context of SMA[1][2][4][5].

Other names

Survival motor neuron 2SMN2centromeric survival motor neuron gene

Modulation of pre-mRNA splicing to increase full-length SMN protein production (ex: Nusinersen, Risdiplam) HDAC inhibition to induce gene expression (ex: vorinostat, romidepsin)