Juvenile primary lateral sclerosis (JPLS) also known as primary lateral sclerosis, juvenile (PLSJ), is a very rare

genetic disorder A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosome abnormality. Although polygenic disorders ...

, with a small number of reported cases, characterized by progressive weakness and stiffness of muscles in the arms, legs, and face. The disorder damages

motor neurons A motor neuron (or motoneuron), also known as efferent neuron is a neuron whose cell body is located in the motor cortex, brainstem or the spinal cord, and whose axon (fiber) projects to the spinal cord or outside of the spinal cord to directly or ...

, which are specialized

nerve cell A neuron (American English), neurone (British English), or nerve cell, is an excitable cell that fires electric signals called action potentials across a neural network in the nervous system. They are located in the nervous system and help to ...

s in the brain and spinal cord that control muscle movement.

Symptoms and signs

Symptoms of JPLS begin in early childhood and progress over a period of 15 to 20 years. Early symptoms include clumsiness,

muscle spasms A spasm is a sudden involuntary contraction of a muscle, a group of muscles, or a hollow organ, such as the bladder. A spasmodic muscle contraction may be caused by many medical conditions, including dystonia. Most commonly, it is a musc ...

, weakness and stiffness in the legs, and difficulty with balance. As symptoms progress, they become more serious and include weakness and stiffness in the arms and hands, slurred speech, drooling, difficulty swallowing, and an inability to walk.

Genetics

Juvenile primary lateral sclerosis is inherited in an

autosomal recessive In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the Phenotype, effect of a different variant of the same gene on Homologous chromosome, the other copy of the chromosome. The firs ...

pattern, which means two copies of the gene in each cell are altered. Most often, parents of affected individuals each carry one copy of the altered gene, but do not show any signs or symptoms. Mutations in the ALS2 gene, found on

chromosome 2 Chromosome 2 is one of the twenty-three pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 2 is the second-largest human chromosome, spanning more than 242 million base pairs and representing almost ei ...

, are responsible for causing 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 in this disorder disrupt the instructions for producing alsin. As a result, alsin is unstable and decays rapidly, or it is disabled and cannot function properly. It is currently unknown how the loss of functional alsin protein causes the death of

and the symptoms of juvenile primary lateral sclerosis.

Diagnosis

Treatment

Treatment of ALS2-related disorders includes

physical therapy Physical therapy (PT), also known as physiotherapy, is a healthcare profession, as well as the care provided by physical therapists who promote, maintain, or restore health through patient education, physical intervention, disease preventio ...

and

occupational therapy Occupational therapy (OT), also known as ergotherapy, is a healthcare profession. Ergotherapy is derived from the Greek wiktionary:ergon, ergon which is allied to work, to act and to be active. Occupational therapy is based on the assumption t ...

to promote mobility and independence and use of computer technologies and devices to facilitate writing and voice communication.

References

External links