9781422272312

Scan here to learn more about genetic predispositions.

Recessive disorders, by contrast, are caused by mutations in recessive genes and produce a 25 percent chance of creating a disease only if both parents have the mutation. This means that such mutations are much less likely to occur in a child. However, the parent is considered a “carrier” of this genetic disorder and may pass the recessive gene to their child even if they don’t exhibit the disorder. The child’s child could subsequently develop this disease. For example, a parent with a recessive disorder that causes type-1 diabetes may not have the disease themselves. However, they pass the gene to their child, who does not develop the disease, because their other parent did not have this mutation. Unfortunately, this person with the recessive gene then has four children with another person who has the same recessive gene mutation—one of their four children is likely to have type-1 diabetes.

16

Nicotine and Genetics: The Hereditary Predisposition