Immunopathology - Week 6 - Tutorial Questions Flashcards
Consider genes.
a) Describe the fundamental role of genes in the human body.
b) Where are they found?
c) Explain the relationship between mutations and genes.
a) Genes are segments of DNA that carry instructions for making proteins, which perform processes on the body, such as building tissue, regulating bodily functions and support the immune system.
b) Genes are found inside the nucleus; they are located in the LOCUS of the chromosomes.
c) A mutation is a change or error in the DNA sequence of a gene. It can disrupt protein production, lead to genetic disorders and increase risk of disease like cancer.
Name some of the types of chromosomal abnormalities.
Trisomy 21 (Down syndrome)
Turner’s syndrome
Klinefelter’s syndrome
Is Down syndrome an example of polyploidy or aneuploidy?
Aneuploidy
What is the chromosomal abnormality in Turner’s syndrome and Kleinfelter’s syndrome?
Turner’s syndrome (XO): 1 sex chromosome only.
Kleinfelter’s syndrome (XXY): an additional sex chromosome.
Explain in simple words what is meant by Autosomal dominant disorder.
This means that if the offspring receives just one of the affected genes, they will manifest the disease.
Explain in simple words what is meant by Autosomal recessive disorder.
These require the individual to have the abnormal gene from both parents, in order to manifest the disease. Receiving one abnormal gene will make them a ‘carrier’, but not have the disease.
Explain in simple words what is meant by X-linked recessive disorder.
This means that the abnormal gene is carried on the X chromosome. (The Y chromosome only has a few dozen genes so is less commonly affected). The majority of these disorders are X-linked recessive.
Females receive an X chromosome from their mother and an X chromosome from their father.
Males receive an X chromosome from their mother and a Y chromosome from their father.
Explain in simple words what is meant by Multifactorial inheritance disorder.
Multifactorial inheritance disorders refer to those disorders which involve defects in a number of different genes in addition to the influence by various environmental factors. The combination of genes and environment contribute to the expression of the disorder.
Consider an autosomal dominant disorder such as achondroplasia. If the father has the disorder (Dd), and the mother is normal (dd).
a)What percentage of their offspring will have the disease?
b)What percentage of their offspring will be carriers?
c)What percentage of their offspring will be disease free and not carriers?
a) 50%
b) 0%
c) 50%
Consider an autosomal recessive disorder such as cystic fibrosis. If one parent is a carrier and the other parent neither a carrier nor suffering the disease:
a) What percentage of their offspring will have the disease?
b) What percentage of their offspring will be carriers?
c) What percentage of their offspring will be disease free and not carriers?
a) 0%
b) 50%
c) 50%
Consider an autosomal recessive disorder such as cystic fibrosis. If both parents are carriers:
a) What percentage of their offspring will have the disease?
b) What percentage of their offspring will be carriers?
c) What percentage of their offspring will be disease free and not carriers?
a) 25%
b) 50%
c) 25%
Consider an X-linked recessive disorder such as haemophilia. If the father has the disorder, and the mother does not:
a) What percentage of their offspring will have the disease? (state the gender)
b) What percentage of their offspring will be carriers? (state the gender)
c) What percentage of their offspring will be disease free and not carriers? (state the gender)
a) 0% of offspring will have the disease
b) 100% of daughters will be carries
c) 0% of sons will be disease free and not carriers
Consider an X-linked recessive disorder such as haemophilia. If the father does not have the disease, and the mother is a carrier:
a) What percentage of their offspring will have the disease? (state the gender)
b) What percentage of their offspring will be carriers? (state the gender)
c) What percentage of their offspring will be disease free and not carriers? (state the gender)
a) 25% overall, specifically 50% of sons.
b) 25% overall, specifically 50% of daughters.
c) 50% of sons and 50% of daughters.
