Human Molecular Genetics Flashcards
(42 cards)
What are environmental factors to development/disease?
Physical
Chemical
Biological
What are genetic factors to development/disease?
Polygenic
Monogenic
What did Richard Doll prove?
That smoking caused lung cancer
How are over 4,000 human diseases caused by?
Single gene defects§
What studies are helpful when determine environmental genetics effects on diseases/developments?
Twin studies
What can defective enzymes have a major consequence for?
Metabolic pathways
Where can mutation occur to cause loss of function or gain of function?
Protein-coding genes
Define dominant referring to modes of inheritance:
Vertical patterns of affected individuals
Define recessive referring to modes of inheritance:
Horizontal patterns of affected individuals
Define autosomal recessive referring to modes of inheritance:
Consanguinity often present between parents
Define autosomal referring to modes of inheritance:
Males and females affected with equal probability
Define X-linked recessive referring to modes of inheritance:
Males affected, female carriers
Define X-linked dominant referring to modes of inheritance:
All daughters of affected males are affected
Define mitochondrial referring to modes of inheritance:
Non-Mendelian
Maternal inheritance
What is consanguinity?
The property of being from the same kinship as another person
How can you tell if the disease is autosomal dominant in a pedigree?
- Affects each generation
- Both sexes
- Normal siblings of affected individuals do not transmit the trait to their offspring.
Example of autosomal dominant diseases:
- Huntington’s disease (Huntington’s chorea)
- Polycystic kidney disease
- Familial hypercholesterolaemia
How can you tell if the disease is autosomal recessive in a pedigree?
- Males and females are equally likely to be affected
- Found in siblings, not parents of affect or the offsprings of affected
- Consanguineous mating
Examples of autosomal recessive:
- Cystic fibrosis
- Phenylketonuria
- Sickle cell anaemia
How can you tell if the disease is x-linked recessive in a pedigree?
- Never passed from father to son
- Males more affected than females
- Passed from an affected grandfather, though his carrier daughters then to half of his grandsons
Examples of x-linked recessive:
- Duchenne muscular dystrophy
- Haemophilia A and B
How can you tell if the disease is non-mendelian (mitochondrial) in a pedigree?
Everyone inherits the condition from the maternal line
Examples of mitochondrial disease:
- Leber’s hereditary optic neuropathy (LHON)
- Myotonic epilepsy and ragged red muscle fibre disease (MERRF)
What 6 complications can affect the interpretation of pedigrees?
- New mutations
- Penetrance
- Expressivity
- Delayed onset
- Anticipation
- Imprinting
