# What is spinal muscular atrophy (SMA)?
Keywords: spinal muscular atrophy, SMA, genetic mutation, SMN1 gene, neuromuscular disease, diagnosis, inheritance, types of SMA

> Spinal muscular atrophy (SMA) is a rare genetic neuromuscular disease caused by a mutation in the SMN1 gene. This page provides information about SMA, including its causes, types, inheritance patterns, and diagnostic processes.

## Details
- [Overview](#): SMA is a rare genetic disorder affecting motor neurons, leading to muscle weakness and atrophy.
- [What causes SMA?](#): SMA is caused by a mutation in the survival motor neuron 1 (SMN1) gene.
- [Types of SMA](#): SMA is classified into types based on age of onset and functional ability, with varying severity within each type.
- [How is SMA inherited?](#): SMA is an inherited condition with a well-understood genetic cause.
- [Diagnosis and Testing](#): Genetic testing is essential to confirm a suspected diagnosis of SMA.
- [About Together in SMA](#): Biogen provides support and information for individuals with SMA and their care teams.