A disease in humans resulting from the degeneration of motor neurons in the lateral columns of the spinal cord. The disease begins with an asymmetric weakness in the limbs and progresses to complete paralysis and death. ALS is sometimes called Lou Gehrig disease after the famous American baseball player who suffered from ALS. In familial cases of ALS, the condition was first shown to be due to mutations in a gene (ALS1) located at 21q22.1 which encoded the enzyme superoxide dismutase (SOD) (q.v.). Next ALS2 was mapped to 2q33, and it encoded a protein (alsin) thought to be a GTPase regulator protein. Familial ALS due to ALS1 is an adult-onset disease, and it shows dominant inheritance; whereas FALS due to ALS2 causes a disease with juvenile onset which shows recessive inheritance. Two other forms of FALS occur: one caused by mutations in ALS3 at 18q21 and the other by mutations in ALS4 at 9q34. However, the cause of 90 percent of ALS cases (sporadic or non-familial) is unknown. See Chronology, 1993, Rosen, Siddique et al.
Subjects: Genetics and Genomics — Medicine and Health.