Title: How Are Genetic Diseases Inherited? | Muscular Dystrophy Association
Headings: About Neuromuscular Diseases
About Neuromuscular Diseases
How Are Genetic Diseases Inherited?
Inheritance Patterns

Content: Some neuromuscular diseases can be caused by a spontaneous mutation that is not found in the genes of either parent — a defect that can be passed to the next generation. Genes are like blueprints; they contain coded messages that determine a person's characteristics or traits. They are arranged along 23 rod-like pairs of chromosomes, with one half of each pair being inherited from each parent. Each half of a chromosome pair is similar to the other, except for one pair, which determines the sex of the individual. Inheritance can happen in three ways: Autosomal dominant inheritance occurs when a child receives a normal gene from one parent and a defective gene from the other parent. Autosomal means the genetic mutation can occur on any of the 22 non-sex chromosomes in each of the body's cells. Dominant means only one parent needs to pass along the abnormal gene in order to produce the disorder. In families where one parent carries a defective gene, each child has a 50 percent chance of inheriting the gene and therefore the disorder.