Hereditary spastic paraplegias are a group of disorders that make muscles in the lower limbs stiff and lead to paralysis (paraplegia) over time.
One specific type, spastic paraplegia type 15 (SPG15), not only affects the lower limbs but also causes problems in the nervous system, such as intellectual disability or dementia. In some cases, individuals with SPG15 may also experience issues with their vision and hearing. Symptoms of SPG15 usually start in childhood or adolescence, and the first sign is often stiffness in the legs or problems with thinking. The neurological symptoms may involve learning difficulties, structural problems in the brain, loss of nerve cells in different brain areas, involuntary movements, and dementia. These problems might get worse over time. Other symptoms can include numbness, tingling, or pain in the arms and legs, difficulties with muscle movements and reflexes, and trouble controlling the bladder. Some people with SPG15 also have issues with the retina in the eye, leading to visual problems. The intensity of these symptoms can vary among affected individuals. Currently, there is no cure for the main cause of SPG15. Treatment focuses on managing the symptoms and may involve physical therapy, occupational therapy, and using devices to assist with walking or a wheelchair. Medications can be prescribed to reduce muscle stiffness and pain. Those with hearing problems may benefit from using a hearing device.
SPG15 is caused by pathogenic (disease-causing) variants in the ZFYVE26 gene and exhibits autosomal recessive inheritance. This means that both parents must be carriers to have a 25% chance to have a child with the condition. The risk of being a carrier is based on a person’s ancestry or ethnic background.
Other names for this condition are Kjellin syndrome and spastic paraplegia and retinal degeneration.