Lect 4 - Inherited disorders

Question 1

define genotype, phenotype, allele, concordance, discordance

Answer 1

genotype - the entire hereditary information

phenotype - the exhibited characteristics

allele - one of two versions of a gene

concordance - if both twins develop the same trait

discordance - if both twins don’t develop the same trait

Question 2

what are the two usual possibilities of an allele

Answer 2

A - dominant, this phenotype is always expressed

a - recessive, phenotype only expressed when paired with another recessive

Question 3

describe cystic fibrosis

Answer 3

cystic fibrosis is an autosomal recessive disease which mutation to CFTR gene results in failure in movement of Na, this causes thick and sticky mucus buildup which can lead to serious infections in places such as lungs and pancreas.

Question 4

describe Huntington’s

Answer 4

a neurological disease characterised by jerky motor function. it is due to changes in HTT gene which plays a main role in nerve function. it is caused by the length of a repeated section of the gene, more repeats means more likely to get the disease

Question 5

what is a type of co-dominant phenotype

Answer 5

blood groups
A
B
O
AB

Question 6

how easy is it to determine mode of inheritance of a disease

Answer 6

the mode of inheritance can rarely be determined from a single pedigree

the more complicated the mode of inheritance, the more genes, more environmental factors and more difficult it is the provide diagnostic certainty