IASM 45: Precision Medicine

Question 1

Arrange the following diseases into autosomal recessive or autosomal dominant

Cystic fibrosis
Familial hypercholesterolemia
Huntington's Disease
Marfan Syndrome
Phenylketonuria
Sickle cell anaemia

Answer 1

Autosomal Recessive- Cystic Fibrosis, Sickle Cell Anaemia, Phenylketonuria
Autosomal Dominant- Huntington, Marfan, Familial hypercholesterolemia

Question 2

What is ‘penentrance’

Answer 2

Percentage of the individuals with the same genotype that expresses the phenotype

Question 3

What is ‘expressivity’

Answer 3

The extent of expression of the phenotype under the same genotype

Question 4

Which gene on Y chromosome specifies sex?

Answer 4

SRY gene

Question 5

Each female has 2 X Chromosomes in their bodies
By Dosage compensation, 1 X Chromosome is silenced and condensed in every cell, they become a Barr Body.
What is the purpose of this

Answer 5

Prevent over expression of genes on X Chromosomes in females

Question 6

Each female has 2 X Chromosomes in their bodies
By ________ compensation, 1 X Chromosome is _____ and ______ in every cell, they become a _______.
The silencing process is ______.
This leads to ________, so females have 50% of cells expressing genes from maternal X chromosome, and 50% from paternal X chromosome.

Answer 6

By Dosage compensation, 1 X Chromosome is silenced and condensed in every cell, they become a Barr Body.
The silencing process is random.
This leads to mosaicism, so females have 50% of cells expressing genes from maternal X chromosome, and 50% from paternal X chromosome.

Question 7

X-linked Recessive disease has higher prevalence in ______; X-linked Dominant disease has higher prevalence in _________.

Answer 7

X-linked Recessive disease has higher prevalence in males; X-linked Dominant disease has higher prevalence in females.

Question 8

Mitochondrial DNA is in ____ shape.

It is paternally/ maternally inherited, regardless of the offspring’s gender.

Answer 8

Mitochondrial DNA is in circular shape.

It is maternally inherited, regardless of the offspring’s gender.

Question 9

1500 genes for mitochondrional function are encoded in _______. Only 37 genes for mitochondrial function are encoded in ________.

Answer 9

1500 genes for mitochondrional function are encoded in Nucleus DNA (nDNA). Only 37 genes for mitochondrial function are encoded in Mitochondria (mtDNA).

Question 10

Heteroplasmy of mtDNA.

There is a _______ for the proportion of mtDNA in order for the disease to be expressed

Answer 10

Heteroplasmy of mtDNA.

There is a threshold for the proportion of mtDNA in order for the disease to be expressed

Question 11

Fertilization for mothers with mitochondrial diseases
______ of mother’s egg is removed.
______ of donor’s egg is removed.

Answer 11

Fertilization for mothers with mitochondrial diseases
Mitochondria of mother’s egg is removed.
Nucleus of donor’s egg is removed.

Question 12

What is the Hardy Weinberg Principle

Answer 12

Allele frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences

Question 13

What are the assumptions of the Hardy Weinberg Principle

Answer 13

No Selection
No Mutation
No Migration
Large Population
Random Mating