Genetics Flashcards
______ is the presence of multiple, genetically different cell lines within the body
Mosaicism
_______ is the probability that a person with a given genotype will exhibit the corresponding phenotype
Penetrance
______ is the occurrence of multiple, seemingly unrelated phenotypic manifestations in different organ systems, as a result of a SINGLE genetic defect
Pleiotropy
Fragile X syn, Huntington disease, friedreich ataxia, and spinocerebellar ataxia are all examples of disorders caused by genes that contain repeated _______ sequences
TRINUCLEOTIDE
_______ syndrome is an AUTOSOMAL DOMINANT connective tissue disorder that classically affects the cardiovascular and musculoskeletal systems as well as the eyes.
Marfan syndrome
Marfan syndrome is a good example of ________ because there is a difference in phenotype although members of the same family have the same genetic mutation.
VARIABLE EXPRESSIVITY
________ is used to describe an inheritied disease state in which sucessive generations experience earlier onset or increased severity of the disease (e.g. Huntington’s Disease)
GENETIC ANTICIPATION
_______ describes a phenominon in which a disease phenotype can be caused by one of SEVERAL genotypes (e.g. osteogenesis imperfecta can come from mutations in COL1A1 or COL1A2)
GENETIC HETEROGENETIY
_______ is a condition in which multiple sets of genetic information are found in the germ cells producing ova or sperm. It can result in mutations being passed to offspring even if the pt’s somatic cells are unaffected
GERMLINE mosaicism
_________ describes instances when different mutations at the same genetic locus cause similar phenotypes
Allelic Heterogneity
WHEELHOUSE: Name the AUTOSOMAL DOMINANT disorder-head circumference in 90th percentile, mid-face hypoplasia, humeral and femoral shortening. Hands have shortened digits and space between 3rd and 4th digits.
Achondroplasia
Achondroplasia is a point mutation on WHAT GENE?
fibroblast growth factor receptor 3 (FGFR3)
WOW ___% of achondroplaisa mutations occur in the fetus of UNAFFECTED PARENTS…its USUALLY the meternal OR paternal allele???
90%…paternal
Wow, I was way off..________ is a rare X LINKED genetic condition that results in a defect in the signal transduction molecule known as Bruton’s tyrosine kinase (BTK)
Bruton AGAMMAGLOBULINEMIA
In Bruton Agammaglobulinemia, what cells cannot mature and leave the bone marrow?
B cells (Bruton = B Cells)
BOOM. YOU READY FOR SOME SHIT: 3 common diseases associated with chormosome 7. GO
1.Cystic Fibrosis 2.Ehlers-Danlos Syndrome 3.Osteogenesis Imperfecta
2 common diseases associated with chromosome 16. GO.
1.polycystic kidney disease 2.tuberous sclerosis
1 common disease associated with chromosome 20. GO.
type I diabetes
1 common disease associated with chromosome 22. GO
DiGeorge syndrome
This SHOULD be wheelhouse…get it there-Early onset osteoporosis, scoliosis, blue sclera of the eye, and hearing loss…WHAT GENE AND PROTEIN PRODUCT ARE INVOLVED??
OSTEOGENESIS IMPERFECTA…COL1A1 and COL1A2 for type I collagen (I LOVE how they name genes!)
Activation of the ____ proto-oncogene which occurs in MEN2 syndrome is an example of an ACTIVATING mutation that predisposes to malignancy. ONLY 1 copy of a proto-oncogene is sufficient to promote tumor development!!!
RET
What cancer is associated with fusion of 2 genes to form a novel protein? In this case, its between chromosomes 9 and 22 (AKA PHILADELPHIA chromosome)
CML (chronic myeloid leukemia)
The mechanism behind MOST heritable cancer syndromes-including Li-Fraumeni Syndrome- is a SINGE _____ cell aquiring a “second hit” and developing a second inactivating mutation in the remaining copy.
SOMATIC
In an X-linked Recessive disorder, what are the chances a duaghter will be a CARRIER? What are the chances a son is AFFECTED?
BOTH are a 1/2 chance
