Genetics

Question 1

Mendelian genetics

Answer 1

Rare diseases
One gene = one disorder

Question 2

Complex trait genetics

Answer 2

Common diseases
Multiple genes
Eg asthma, hypertension

Question 3

Somatic genetics

Answer 3

Cancer

Question 4

Mosaicism

Answer 4

Presence of 2 population of cells with different genotypes in an individual

Question 5

Different types of mosaicism

Answer 5

Inherited
De novo
Somatic

Question 6

Inherited mosaicism- child heterozygous in all cells

Answer 6

• parent has mutation in all cells
• parent has mutation that affects germline and somatic cells
• parent has germline mosaic mutation

Question 7

De novo mosaicism - child heterozygous in every cell

Answer 7

• parent has mutation in a single gamete
• mutation occurs in zygote within first few cell divisions

Question 8

Somatic mosaicism

Answer 8

• child has somatic mutation that occurs in postzygotic development = present in a percentage of cells
• child has mosaic mutation that occurs later in development = affects fewer cells

Question 9

Genotype-phenotype correlations

Answer 9

The position and nature of the mutation within a gene can determine the manifestation of the condition in an individual

Question 10

ADPKD

Answer 10

Autosomal dominant polycystic kidney disease

Question 11

Prevalence of ADPKD

Answer 11

1 in 500-1000
All ethnic groups
5-10 million world wide

Question 12

Extrarenal manifestations of ADPKD

Answer 12

Hypertension
Mitral prolapse
Pancreatic cysts
Seminal vesicles/ejaculatory duct cysts
Hepatic cysts
Intracranial aneurysm

Question 13

Two proteins that when mutated cause ADPKD

Answer 13

Polycystin-1<— most common 75%
Polycystin-2

Question 14

Where are cysts most common in ADPKD

Answer 14

Kidney
Liver