Spastic Paraplegia Type 4 (SPG4)

Spastic paraplegia 4 (SPG4) is an inherited neurodegenerative disorder and is the most common disorder in the hereditary spastic paraplegia (HSP) group. SPG4 is an autosomal dominant disorder caused by mutations in the SPAST gene. Mutations in the SPAST gene disrupt the production of spastin, which is necessary for the regulation of microtubules. There are two major types of SPG4, the pure type and the complex type. Pure SPG4 is the most common form and is characterized by the progressive loss of spasticity in the legs, leading to stiffness and difficulty walking. Complex SPG4 has more widespread symptoms involving the nervous system. Like pure SPG4, symptoms of Complex SPG4 include muscle weakness in the legs, but can also include loss of sensation in the feet and cognitive impairment among others. Symptoms of SPG4 can begin at any age, but most commonly begin in early adulthood.

A Cow Model of SPG4

A similar disease occurs in brown swiss cattle called bovine spinal dysmyelination (BSD), more commonly known among dairy farmers as spinal demyelinization (SDM). This disease is also caused by a mutation in the SPAST gene. Our lab is in the process of obtaining cattle that are carriers of this disease so that we may study the SPAST gene and develop a gene therapy to target it.