Single Gene Disorders Flashcards
Why does Mitochondrial DNA mutate at a higher frequency than nuclear DNA?
Mitochondrial DNA replication and repair is not as efficient as nuclear replication and repair.
What is the most common mutation in the CFTR gene that results in Cystic Fibrosis?
The most common mutation is ΔF508 - a single amino acid deletion.
What is the Hardy-Weinberg equation for calculating the incidence of a genetic disease in a population?
p2 + 2pq + q2 = 1
What leads to Haploinsufficiency?
The inheritance of only a single functional copy of a gene. This single copy is unable to produce a sufficient amount of the gene product to maintain the wild-type phenotype. Consequently, this leads to a diseased state.
What is Alkaptonuria?
It is a metabolic disease caused by the body’s inability to process the amino acids phenylalanine and tyrosine, resulting in the accumulation of homogenetisic acid and alkapton in the urine.
What causes Alkaptonuria?
It is caused by a mutation in the gene that encodes for enzyme homogenetisic acid oxidase. As a result homogenetisic acid cannot be metabolised to acetoacetic acid, and so accumulates in the body.
What is Phenylketonuria?
It is a metabolic disease caused by the body’s inability to process the amino acid phenylalanine.
What causes Phenylketonuria
It is caused by a mutation in the gene that codes for the enzyme phenylalanine hydroxylase. As a result, phenylalanine cannot be metabolised to tyrosine, and so accumulates in the blood.
What does a decrease in tyrosine lead to?
A decrease in melanin pigment.
What does an increase in phenylalanine lead to?
Intellectual impairment.
