Genetic Factors and Disease Flashcards
Causes of disease:
Genetic, Multifactorial, Environmental
Eg. of genetic diseases:
Downs syndrome
* Cystic fibrosis
* Huntington disease
* Haemophilia
Eg. of multifactorial diseases:
- Spina bifida
- Cleft lip/palate
- Diabetes
- Schizophrenia
Eg. of environmental factors on disease:
- Poor diet
- Infection
- Drugs
- Accidents
Locus:
The position of a allele on a gene
Genotype:
Genetic constitution of an individual
Phenotype:
Appearance of an individual which results from the interaction of the environment and the genotype
Allele:
One of several alternative forms of a gene at a specific locus
What is cystic fibrosis? What type of condition is it? Chance of being a carrier?
Chronic condition affecting mainly the lungs and gut
Autosomal recessive condition
25% of carrier
What is an x linked inheritance condition?
Who can’t pass it on
Caused by a mutation in genes on the X-chromosome. e.g. haemophilia and Duchenne muscular dystrophy
Can never be passed from father to son, X chromosome comes from mother
What is lyonisation?
One of the two X chromosomes in every cell in a female is randomly inactivated early in embryonic development.
To prevent female cells having twice as many gene products as males
What are the inactivated chromosomes in females cells called?
Barr body
Its packed in heterochromatin
What is imprinting?
Where only 1 out of 2 alleles of the gene is active.
What is Knudson’s two hit hypotheses:
Gene mutations may either be inherited or acquired during a persons life
Classifications of genetic diseases:
Chromosomal
Mendelian (autosomal dominant/recessive or x-linked)
Non-traditional - Mitochondrial, imprinting, mosaicism
