General Concepts Flashcards
what are the human diseases classification according to geneticists?
- chromosomal disorders
- single gene disorders
- polygenic
how to find whether a certain disease has a genetic component
through the use of
- classic family study
- twin studies
- adoption studies
steps to classic family study
- identify the family
- determine the proportion of the relatives affected
- calculate the lifetime risk
what are the problems with twin studies
- rarity of twins
- concordant pairs are more likely to be enrolled
- MZ twins often share more environment than Dz
what are the practical conclusions to from the liability threshold model?
- closer the sick relative, the greater the risk
- having more than one affected relative means risks are even greater
- more severe the disease is in proband, the stronger the risk for relatives
- sometimes there is a difference in the incidence of the disease between genders
what are the ways to find Common disease common variant genes (CDCV genes)
- linkage analysis
- association studies
- linkage equilibrium analysis
ankylosing sponylitis
HLA B27 disease, associated with spine, back, and inflammation problems
what are the thoughts to get from association to causation?
- polymorphism is causative for the disease
- association is a false positive due to random chance
- polymorphism is a associated bc of some systematic bias in the biology, study samples, and analysis
- polymorphism is in disequilibrium with the true causative allele
how to prove that the variant is actually causative for the disease?
- indirect clues like using snp promoter changes in gene expression
- sherlock holmes method
what are the steps to genome wide association analysis?
- scan the entire genome with a dense collection of genetic markers
- calculate association at teach polymorphic marker position along the genome
- identify regions which show a significant association
- study possible disease contributing genes from the linked region in functional assays
inflammatory bowel disease
associated with NOD2 gene
environmental factors for alzheimers are:
- head injury
- high blood pressure
- heart disease
- stroke
- diabetes
- high cholesterol
- active learning
- smoking
punch drunk syndrome
- env factor for alzheimers
- caused by repeated cerebral injury
- weakness in lower limbs
- unsteadiness of gait
- slowness of muscular movements
- tremors of hand
- dysarthria
- slow thinking
coronary artery disease
- hypertension
- atherosclerosis
- coronary heart disease
- stroke
why is high plasma glucose bad?
- activation of the protein kinase CB
- glycation
- oxidative stress
- depletion of NAD+ (metabolic pseudohypoxia)
what are the environmental and genetic factors of diabetes type 1
env: drinking too much cow milk young, viral infection of coxsackie, mumps, and rubella
Genetic: IDDM1 locus with HLA region and IDDM2 locus with insulin gene
diabetes type 2
- hyperinsulinemia leading to insulin resistance
- treated by diet and hypoglycemics
- high concordance
- associated with obesity
hirschprung disease
- absence of ganglion cells in the parts of the colon and rectum
- short segment affects rectum and small portion of the colon
- long segment affects longer portion of the intestine
- ologogenic disease
hyperhomocysteinemia
- caused by deficiency in vit B and folate in diet or MTHFR to T mutation
- hypothyroidism
- MTHFR C677T
- deep vein thrombosis
what are the summary risks with elevated homocysteine levels
- coronary artery disease
- peripheral artery disease
- dementia
- neural tube defects
what are the different kinds of point mutations
- missense (sickle cell)
- nonsense (familial hypercholesterolemia)
- silent
- frameshift mutations (cystic fibrosis)
what is the damage control for protein length
- mRNAs with pre mature stop codons get degraded
2. if truncated protein made, gets degraded in the er before delivery to membrane
regulatory mutations with interesting phenotypic consequences
- DARC-resistance to infection with malaria
- LCT-lactose persistence
- Pdyn-memory and emotional status