Spastic paraplegia type 11 family (Spastic paraplegia type 11) - Gen SPG11.  

The spastic paraplegia type 11 is part of a group of genetic alterations known as hereditary spastic paraplegia. These changes are characterized by spasticity and development of paraplegia. Hereditary spastic paraplegia the are divided into two types: pure and complex. Pure types involving the lower extremities. Complex types involving the lower extremities and may affect the upper extremities to a lesser degree. Spastic paraplegia complex also affect the structure or function of the brain and peripheral nervous system consists of the nerves that connect the brain and spinal cord to muscles and sensory cells that detect sensation like touch, pain, heat , and sound. The spastic paraplegia type 11 is a part of the complex type hereditary.

The disease involves spasticity of leg muscles and muscle weakness. In almost all individuals with this type of spastic paraplegia, the connection between brain, right and left hemispheres, is abnormally thin. People with this form of spastic paraplegia may also have sensory neuropathy, motor neuropathy, mental retardation, hyperreflexia of the lower limbs, dysarthria, decreased bladder control and amiotrofia. Less common features include dysphagia, lifting the arch of the foot, scoliosis and nystagmus. Although the onset of symptoms is highly variable, changes in muscle tone and difficulty walking are evident in adolescence. Many of the features of the disease are progressive. Most people have a diminished intellectual capacity and an increase in muscle weakness and nervous disorders in time. As the disease progresses, some people require a wheelchair.

This process is due to mutations in the gene SPG11, located in the long arm of chromosome 15 (15q14). This gene encodes the protein espatacsina. Although the exact function is unknown, this protein is present throughout the nervous system. It is believed to help control the activity of certain genes or play a role in transporting proteins. In addition, the protein may be involved in maintenance of axons which transmit impulses through the nervous system.

There are more than 65 mutations in the gene causing the SPG11 spastic paraplegia type 11. Mutations in the gene structure change espatacsina protein, but the effect that espatacsina altered protein has on the nervous system is unknown. It is thought that mutations can cause signs and symptoms of the disease by interfering with the proposed function of the protein in maintaining axons.

This disease is inherited in an autosomal recessive pattern, that is, both copies of the gene in every cell must have mutations for alteration is expressed. The parents of an individual with an autosomal recessive disease have a copy of the mutated gene, but usually show no signs and symptoms of the disease.  

Tests in IVAMI: in IVAMI perform detection of mutations associated with spastic paraplegia type 11, by complete PCR amplification of the exons of the gene SPG11, and subsequent sequencing.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).