What is Spastic Paraplegia Type 15?
Hereditary spastic paraplegias are a group of disorders that cause progressive muscle stiffness (spasticity) in the lower limbs, leading to paralysis (paraplegia). Complex hereditary spastic paraplegias, such as spastic paraplegia type 15 (SPG15), affect the lower limbs and cause neurological impairment, which may include intellectual disability or dementia. Less commonly, some affected individuals have vision and hearing problems. SPG15 is caused by harmful genetic changes (mutations) in the gene ZFYVE26.
The onset of symptoms in SPG15 typically occurs in childhood or adolescence. Often either leg stiffness or intellectual disability is the first symptom. Neurological symptoms associated with SPG15 may include structural brain malformations, learning difficulties and intellectual disability, loss of nerve cells in different parts of the brain, involuntary movements, and dementia. These issues may be progressive. In addition, individuals may experience numbness, tingling, or pain in the arms and legs; problems with muscle movements and reflexes; and issues with bladder control. Some individuals with SPG15 also have visual impairment, due to problems with the retina in the eye. The severity of each of these symptoms is variable in affected individuals.
How common is Spastic Paraplegia Type 15?
Incidence of autosomal-recessive hereditary spastic paraplegias is approximately 1 in 50,000 births. SPG15 accounts for 3 to 15% of cases of autosomal-recessive hereditary spastic paraplegias, depending on region. In areas where relatedness between parents of offspring (consanguinity) is common, the frequency of cases is likely higher.
How is Spastic Paraplegia Type 15 treated?
There is no cure for the underlying cause of this condition. SPG15 is treated symptomatically and treatment may include physical therapy, occupational therapy, and devices to assist with walking or use of a wheelchair. Various medications may reduce muscle stiffness and pain. Patients with hearing impairment may use a hearing device.
What is the prognosis for an individual with Spastic Paraplegia Type 15?
Individuals with SPG15 typically have progressive spasticity that will often necessitate walking assistance or a wheelchair approximately 15 years after the diagnosis. Remaining outcomes will vary based on the severity of symptoms; however, this condition is not expected to shorten lifespan.