Genetic disorders

Question 1

Types of mutation

Answer 1

• small-scale mutations
  + point mutations - single base change
  + frameshift mutations - change to a number of bases
  (not a multiple of 3)
  ~ deletion, insertion, substitution
• large-scale mutations
  + changes to large segments of/whole chromosomes

Question 2

Alleles

Answer 2

• alternate version of gene at an identical locus in a pair of chromosomes

Question 3

Homozygotes

Answer 3

• have identical alleles at particular locus

Question 4

Heterozygotes

Answer 4

• have non-identical alleles at particular locus

Question 5

Modes of inheritance

Answer 5

• autosomal
• sex-linked
• dominant
• recessive

Question 6

Genetic Disorders

Answer 6

- autosomal dominant
   \+ e.g. familial hypercholesterolaemia
- autosomal recessive
   \+ e.g. cystic fibrosis
- multifunctional disorders
   \+ e.g. alzheimer's disease

Question 7

Cystic fibrosis diagnosis

Answer 7

• sweat test (tests Cl- levels)

- sequencing CFTR gene is gold standard

Question 8

Genetic diseases - diagnostic testing

Answer 8

• carrier screening
• prenatal testing
• newborn screening
• testing includes:
  + chromosomal analysis
  + DNA sequencing
  + DNA probes
  + genetic markers