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Autosomal Dominance. What’s an Autosome?. Autosome : Non sex chromosome Ex: Autosomal disorders: gene for the disease is found on chromosomes 1-22 Autosomal Recessive Inheritance Must inherit two copies of the recessive allele to be affected Healthy is dominant (HH or Hh )
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What’s an Autosome? • Autosome: Non sex chromosome • Ex: Autosomal disorders: gene for the disease is found on chromosomes 1-22 • Autosomal Recessive Inheritance • Must inherit two copies of the recessive allele 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 dominant allele 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 (HH or Hh) • Homozygous dominant: early death and don’t survive to reproduce • Heterozygous live into adulthood • Healthy is recessive (hh) • Familial hypercholesterolemia (FH) causes abnormally high levels of cholesterol in blood leading to heart disease/stroke by age 30. Complete a pedigree chart for all 5 people mentioned in the following story: Paul has FH and Stacy is healthy. The two have 3 children. After testing, the middle child is the only healthy child. h h Hh hh H h H h Key H = FH disease h= healthy Paul Stacy H disease disease h h h h Hh hh Hh h healthy healthy
Video about Huntington's disease • Autosomal dominant disorder • Brain cells start to die in late 30’s • Causes uncontrollable muscle jerking • Death usually in 40’s-50’s • No treatments Click if YouTube video doesn’t work
Autosomal Dominance Inheritance • Disease is dominant (HH or Hh) • Homozygous dominant: early death and don’t survive to reproduce • Heterozygous live into adulthood • Healthy is recessive (hh) • Huntington’s disease is an autosomal dominant disorder found on chromosome 4. Complete a pedigree chart for all 3 people mentioned in the following story: 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 chanceof having a healthy child, now that Betty is pregnant. H h Hh Hh H H H h Key H = Huntington’s disease h = healthy H Marcus Betty Disease (severe) disease H h h h h ? disease healthy
Review • How are autosomal dominant disorders different from autosomal recessive disorders? • What are the possible genotypes of someone with an autosomal dominant disorder? • In all likelihood, what is the genotype of an adult with an autosomal dominant disorder? • Complete a pedigree from the following story: Jerome is concerned about Huntington’s disease (HD) since his father recently passed away due from the disorder. After a gene test, he is found to not have the HD gene. He marries Raquel and they are now preparing for their first child. • What is the likelihood of the child having HD if Raquel is healthy? • What is the likelihood of the child having HD if Raquel has HD?