What Chromosome Is Affected by Lou Gehrig's Disease?

Lou Gehrig's disease is a neurodegenerative disease that carries the scientific name amyotrophic lateral sclerosis. Lou Gehrig's disease affects motor neurons carrying messages from the brain to the spinal cord and on to the muscles of the body.

Hereditary

• Lou Gehrig's disease is only hereditary in a small number of families. The ALS Association reports 90 percent of adults affected by Lou Gehrig's disease have no family history of ALS in close family members.

Familial ALS

• Those diagnosed with Lou Gehrig's disease who have a family history of the disease are said to have familial ALS (FALS). A defective gene inherited from a parent disrupts the sequence of genes in the body, causing the genes to function incorrectly. A disrupted gene is known as a mutated gene.

Chromosomes

• The body of a healthy person has 23 pairs of chromosomes, 22 pairs are shared between males and females with the 23rd carrying two X chromosomes in females or one X and one Y chromosome in the male pair.

Autosomal Dominant

• Lou Gehrig's disease has three patterns of gene mutation, with the most common described as autosomal dominant. This means the affected chromosome is in the first 22 pairs of chromosomes shared between male and female humans; only one gene must mutate for the chances of contracting ALS to be increased.

Chromosome 21

• The most common chromosome affected in FALS is chromosome 21. The ALS Association reports chromosome 21 being affected in around 20 percent of cases of inherited Lou Gehrig's disease. This gene mutation is known as superoxide dismutase or SOD1.