neurons**, which control movement.
Sensation such as touch, smell, hearing, and taste is generally preserved. Mayo Clinic notes that ALS usually does not affect bladder function or the senses. ([Mayo Clinic][1])
That distinction can help doctors differentiate ALS from conditions that primarily affect sensory nerves.
However, symptoms should never be interpreted in isolation.
## Does ALS Cause Pain?
Pain is generally not one of the characteristic early symptoms of ALS.
Mayo Clinic notes that pain is usually absent early in the condition. ([Mayo Clinic][1])
Pain can develop later because of muscle stiffness, immobility, joint strain, or other complications, but unexplained pain alone is not a typical early warning sign.
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## What Causes ALS?
For most people, the exact cause is unknown.
Approximately **90% of ALS cases are sporadic**, meaning there is no obvious family history. Around 10% are familial and linked to inherited genetic variants. ([NINDS][
