Genetics

Question 1

Risk of grandparents and aunts/uncles of affected individuals of autosomal recessive diseases

Answer 1

50%

Question 2

Carrier risk of known unaffected siblings of autosomal recessive diseases

Answer 2

67%

Question 3

Carrier risk of sibling of unknown disease status

Answer 3

50%

Question 4

X-Linked Lethal Traits

Answer 4

Males do not reproduce, 2/3 odds mother is carrier and 1/3 odds of de novo mutation

Mothers of affected sons have 15% risk to have affected offspring due to germline mosaicism

Question 5

Linkage Analysis

Answer 5

Analyzes families to identify heritable, rare, high penetrance, monogenic diseases.

Ex: breast cancer –> identify polymorphism close to genes, identify which are normally expressed using northern blot / real time PCR, and then look to see what is or isn’t expressed in mutated cells to identify candidate gene

Question 6

Genome-Wide Analysis

Answer 6

Identify genetic risk factors in common, low penetrance, polygenic / environmental disease.

Ex: age-related macular degeneration –> look at SNPs in people with disease vs. healthy controls and find SNPs in risk alleles –> typically very low penetrance, lots of people w/ the variant do NOT have the disease