Autosomal Dominance Inheritance

1. Autosomal Dominance Inheritance

2. What’s an Autosome? • Autosome: refers to chromosomes 1-22 • Ex: Autosomal disorders: gene for the disease is found on chromosomes 1-22 • Autosomal Recessive Inheritance • Must inherit two copies of the disorder to be affected • Healthy is dominant (HH or Hh) • Disease is recessive (hh) • Ex: Cystic fibrosis, PKU, Albinism, Sickle cell anemia • Autosomal Dominance Inheritance • Only need to inherit one copy of the disorder to be affected • Disease is dominant (HH or Hh) • Healthy is recessive (hh) • Ex: Familial hypercholesterolemia (also called FH), Huntington’s disease, Neurofibromatosis

3. Autosomal Dominance Inheritance • Disease is dominant (FF or Ff) • Homozygous dominant: early death and don’t survive to reproduce • Heterozygous live into adulthood • Healthy is recessive (ff) • ex: Paul has familial hypercholesterolemia and Stacy is healthy. The two have 3 children. After testing, the middle child is the only healthy child. Ff ff f f Paul Stacy F f F f Key F = FH disease f = healthy F disease disease Ff ff Ff f f f f f healthy healthy

4. Autosomal Dominance Inheritance • Huntington’s disease is a dominant disorder found on chromosome 4. Betty and Marcus met at a support clinic they have been attending to help them cope with the knowledge of their illness with Huntington’s disease. They would like to know the risk of having a healthy child, now that Betty is pregnant. Hh Hh H h Marcus Betty H H H h Key H = Huntington’s disease h = healthy H disease disease ? H h h h h disease healthy