Transcript Autosomal Dominance Inheritance

Autosomal Dominance Inheritance
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
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
Paul
Stacy
Key
disease
disease
F = FH disease
f = healthy
healthy
healthy
Ff
ff
Ff
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
Marcus
Betty
Key
disease
disease
H = Huntington’s disease
h = healthy
disease
healthy
?