Juvenile primary lateral sclerosis

Juvenile primary lateral sclerosis is a rare disorder characterized by progressive weakness and stiffness of muscles in the arms, legs, and face. This disorder damages motor neurons, which are specialized nerve cells in the brain and spinal cord that control muscle movement.

Symptoms of juvenile primary lateral sclerosis begin in early childhood and progress over a period of 15 to 20 years. Early symptoms include clumsiness, muscle spasms, weakness and stiffness in the legs, and difficulty with balance. As symptoms progress, they include weakness and stiffness in the arms and hands, slurred speech, drooling, difficulty swallowing, and an inability to walk.

Juvenile primary lateral sclerosis is a rare disorder, with a small number of reported cases.

Mutations in the ALS2 gene cause juvenile primary lateral sclerosis.

The ALS2 gene provides instructions for making a protein called alsin. Alsin is abundant in motor neurons, but its function is not fully understood. Mutations in the ALS2 gene alter the instructions for producing alsin. As a result, alsin is unstable and decays rapidly, or it is disabled and cannot function properly. It is unclear how the loss of functional alsin protein damages motor neurons and causes juvenile primary lateral sclerosis.

Read more about the ALS2 gene.

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.