Hereditary spastic paraplegia

Hereditary spastic paraplegia is a general term for a group of rare inherited disorders that cause weakness and stiffness in the leg muscles. Symptoms gradually get worse over time.

It's also known as familial spastic paraparesis or Strümpell-Lorrain syndrome.

It's difficult to know exactly how many people have hereditary spastic paraplegia because it's often misdiagnosed. It's thought to affect about 3 in every 100,000 people.