SNP Shot: Genomic Insights

Spastic paraplegia type 3A belongs to a category of inherited conditions called hereditary spastic paraplegias (HSPs). HSPs are marked by stiffness (spasticity) and weakness in the legs (paraplegia). HSPs are generally classified as either pure or complex. Pure HSPs primarily affect the legs, while complex HSPs involve other parts of the body. Complex HSPs may include visual impairments, cognitive changes, difficulty walking, and nerve problems (neuropathy). Spastic paraplegia type 3A is generally considered a pure HSP, but some individuals may present with complex features.

Besides spasticity and weakness, which generally impact both legs to the same degree, individuals with spastic paraplegia type 3A may also develop muscle atrophy (amyotrophy) in the lower limbs, bladder control issues, scoliosis (an abnormal spinal curve), peripheral neuropathy (loss of feeling in the feet), or pes cavus (high-arched feet). The symptoms of spastic paraplegia type 3A often begin before age 10, with an average onset age of 4 years. The condition may gradually worsen, potentially requiring mobility assistance later in life.

Inheritance:

Spastic paraplegia type 3A follows an autosomal dominant inheritance pattern. This means that having only one copy of the mutated gene in each cell is enough to cause the condition. About 95% of individuals with spastic paraplegia type 3A inherit the altered gene from an affected parent.