Genetics Flashcards
def: codominance
both alleles contribute to phenotype (blood type)
def: variable expressivity
phenotype varies amoung individuals with same genotype (NF1)
def: incomplete penetrance
not all individuals with mutant genotype show the mutant phenotype (BRCA1 - not everyone gets cancer)
pleiotropy
one gene contributes to multiple phenotypic effects (PKU - lots of different signs/sx)
imprinting
differences in gene espression depending on if the mutation is maternal or paternal (Prader-willi/angelman’s)
anticipation
increased severity, or earlier onset of dx in each generation (huntington’s)
locus heterogenetity
mutations at different loci can produce the same phenotype (marfan’s, MEN2B and homocysturia all cause marfanois habitus)
heteroplasmy
precesnes of normal and mutated MtDNA
hardy-weinberg shows
Psq +2pq + qsq. Psq is the frequency of homozygosity for allele P. Qsq is the frequency of homozygosity for allele Q. 2PQ is the frequency for hetrozygosity
prader-willi imprinting from the
Paternal 15 not expressed)
angelMan;s imprinting from the
Maternal 15 not expressed
MR, hyperphagia, obesity, hypogonadiasm, hypotonia
Prader-Willi
MR seziures, ataxia, inappropraite laughter
Angelman’s
ragged red fibres in muscle biopsy
myopathy of mtDNA inheratance
genetic defect in Achondroplasia
FGF receptor 3 (AD)
genetic defect in AD polycystic kidney dx
PKD1 on 16 (AD)
genetic defect in FAP
APC gene on 5 (AD)
genetic defect in famial hypercholesterolemia
defective/absent LDL receptor (AD)
signs of hereditary hemorrhagic telangiectasia
teleangiectasia, recurrent nosebleeds, skin discolorations, AVMs (AD)