Genetic and pathobio of disease Flashcards
application of genetic knowledge (3)
- confirmation of exact diagnosis and counselling
- cancer prognosis and treatment
- risk assessment in other family members
why are genetic important in peds
- 2-3% born with congenital anomaly
2. leading cause of death in neonatal period
importance of genetics in adults
5% of under 25 dev. illness with genetic component
- 67% chance if consider CV and cancer
what is spectrum of genetic influence
entirely genetic to entirely environmental
when do different disease types show up
chromosomal - before birth
single gene - childhood
multifactorial - later in life
what are chromosomes
physically separate strand of DNA
what are human chromosomes
23 + a sex
def. karytype
lab technique that produces picture of chromosomes
def. aneuploidy
abnormal number of chromos
2 types of aneuploidy
- consitiutioknsal - every cell
2. somatic - only in some cells - cancer
what is chromosome structure
short (p) arm and long (q) arm separated by centromere
what are other chromo imbalances
micro deletions and duplications - can’t see on karyotype
how to see micro
flourescence in situ (FISH)
what is FISH
use a probe with are looking for to flouresce that region
what is chromo microarray
like doing hundreds of FISH at once
def. proteome
constellation of all proteins in a cell
what is average gene size
3000 nucleotides
what is actual coded portion of gene
exons
what is central dogma
DNA>RNA>protein
3 ways a single gene defect can be inherited
- autosomal dominant
- recessive
- x-linked - affects male preferentially
look at the genograms
do it
def. mutation
- perm. change in the DNA sequence of a gene
- may be single nucleotide to large sequence
2 types of mutaitons
- germline - from parents
2. somatic - aquired
3 ways mutations can happen
- point mutations
- insertion mutations
- deletions
poss. results of point
silent, missense, nonsense (stop)
def. polymorphism
genetic changes that are common in the pop. (>1%)
what is common form of polymorphism
SNP - single nucleotides
def. locus
specific location on a chromosome - usually refers to a specific gene
def. allele
alternate forms of a gene
how do mutations lead to disease
usually with gain or loss of function
what is loss of function
- most genetic disease
- proteins have less or no function
- most reccesive mutations
what is gain of function
- proteins with new or abnormal function
- typically autosomal dominant
example of loss of function and gain of function
loss - CF - loss of CFTR transporter - mucous
gain - achondroplasia - fibroblast growth facotr gene - increased chondorcyte inhibition
4 approaches to pathobiol of disease and genetics
- multifactorial or genetic
- chromosomal
- molecular
- other
