Amyotrophic lateral sclerosis (ALS) is the most common degenerative disease of the motor neuron system. It is characterized by progressive muscular paralysis reflecting degeneration of motor neurons in the primary motor cortex, corticospinal tracts, brainstem and spinal cord. Incidence in Western countries averages around 1/50,000 per year and prevalence averages around 1/20,000. Onset occurs early, and delayed walking is observed in patients. Speech may get slurred later. Generalized muscle weakness is progressive, leading to dyspnea and excessive fatigue with mild exertion even during the first decades. Disease progression leads to shortness of breath and excessive tiredness which may cause death. Juvenile ALS has many of the clinical features of adult-onset ALS except for its apparent autosomal recessive mode of inheritance and earlier onset.
The diagnosis of ALS is based on clinical history, examination, and electromyography testing might contributes to the diagnostic accuracy. ALS is an incurable fatal disease, with median survival of 3-5 years. Treatments for ALS are designed to relieve symptoms and improve the quality of life for patients. Supportive care is best provided by health care professionals to keep the patients as mobile and comfortable as possible.
Amyotrophic lateral sclerosis 2 (ALS2) is an autosomal recessive form of juvenile ALS and has been mapped to human chromosome 2q33. The ALS2 gene is expressed in many tissues and cells, and encodes a protein particularly abundant in motor neurons, the specialized nerve cells in the brain and spinal cord that control the movement of muscles including neurons.