Genetics

Question 1

Albinism
What is the genetic phenomena for oculocutaneous albinism?

Answer 1

Locus heterogeneity; similar phenotype produced by mutations in different genetic loci.
Since oculocutaneous albinism is autosomal recessive, there needs to be a recessive mutations occurring on different chromosomes.

Question 2

Gene Expression and Regulation:
What is the genetic phenomenon resulting in Turner Syndrome?

Answer 2

Aneuploidy: an abnormal number of chromosomal copies is a result from deletion or mosaic dysfunction of one X chromosome in females.
- Other examples of aneuploidy include trisomy 13,18, and 21

Question 3

Gene Expression and Regulation:
What is the genetic phenomenon resulting in von Willebrand disease?

Answer 3

Penetrance
Meaning a disease specific genotype will produce the phenotype. If their coagulation cascade is normal then it is incomplete penetrance.

Question 4

Gene Expression and Regulation:
What is the genetic phenomenon resulting in Lynch Syndrome?

Answer 4

Loss of heterozygosity
A normal allele of a gene is lost leaving the abnormal allele exposed for expression.

Question 5

Gene Expression and Regulation:
What is the genetic phenomenon resulting in Phenylketonuria?

Answer 5

Pleiotropy, a phenomenon in which one genetic mutation leads to various unrelated phenotypic manifestations. Mutations in the PAH gene for phenylalanine hydroxylase, results in various phenotypic features like hypopigmented skin, seizures, and character musty odor of skin and urine.

Question 6

Gene Expression and Regulation:
What is the genetic phenomenon resulting in Prader-Willi Syndrome?

Answer 6

Uniparental Disomy
- inheriting both alleles from the same gene from one of the parents, resulting in the inactivation of the opposing parent’s allelic contribution.
PWS comes from maternal uniparental disomy resulting in Hyperphagia/Obesity, hypogonadism, developmental delay, and behavior problems.

Question 7

Clinical Genetics: Pedigrees and Modes of Inheritance
What is the inheritance pattern of myoclonic epilepsy with ragged red fibers (MERRF)

Answer 7

Mitochondrial disorder

Question 8

Bootcamp: Single Stranded repair
Where in the cell cycle does Nucleotide Excision Repair typically occur in?

Answer 8

G1 phase of the cell cycle.