Skip to main content
Fig. 1 | Neurological Research and Practice

Fig. 1

From: Therapy development for spinal muscular atrophy: perspectives for muscular dystrophies and neurodegenerative disorders

Fig. 1

Genetic cause of spinal muscular atrophy (SMA). The human survival motor neuron genes (SMN1 and SMN2) are located in an inverse duplicated region on chromosome 5q13.2. On DNA level, the two genes only differ by one functionally relevant nucleotide exchange within exon 7. This transition from C to T results in the generation of an exonic splicing silencer (ESS) site leading to exon 7 skipping on mRNA level. While SMN1 codes for the functional, full-length SMN protein, SMN2 predominantly (~ 90%) produces a truncated, non-functional version of the protein. SMA is caused by homozygous deletions of SMN1 resulting in highly reduced SMN protein levels. However, the number of SMN2 copies that determines the amount of functional SMN protein can modify disease severity

Back to article page