Intro to Medical Genetics Flashcards
Define genomic medicine
the promise to tailor health care at the individual level by using patients’ genomic
information. Allows us to prescribe the best treatment for each patient, avoid adverse
drug reactions, and identify and monitor individuals at high risk from disease
What’s the most common skeletal dysplasia? Why is it common? What
complications are associated with it?
Achondroplasia. It’s common because the particular gene is hypermutable. Airway
obstruction, obesity, spinal stenosis L1-L4, cord compression. They have short stature (specifically shortening of the bones closest to the trunk, ie femur) but they have normal
intellect
What gene is associated with achondroplasia? How does the age of the parents play
into risk factors?
mutations in FGFR3 (99% in the same nucleotide resulting in a missense mutation).
It’s autosomal dominant, 100% penetrance, and can happen more frequently with
advanced paternal age.
What does FGFR3 code for?
transmembrane TK receptor
What is the lethal type of skeletal dysplasia called?
Thanatophoric dysplasia
What mutation causes thanatophoric dysplasia?
a mutation in FGFR3 (like achondroplasia) results in a missense or nonsense mutation.
What is the normal function of FGFR3 (fibroblast growth factor receptor 3)?
It’s a transmembrane TK receptor that binds FGRs. The normal function of FGFR3 is
to serve as a negative inhibitor of bone growth during ossification (inhibits proliferation
of chondrocytes within the growth plate).
Mutations in FGFR3 like we see in Thanatophoric dysplasia, hypochondroplasia, and
achondroplasia cause what at the molecular level?
gain of function mutations cause ligand-independent activation of FGFR3 which
inappropriately inhibits chondrocyte proliferation within the growth plate. Because all
three disorders are caused by different mutations in the same gene these disorders are
allelic.
What type of disease is cystic fibrosis?
autosomal recessive
A disorder that has multi-system organ involvement is said to have _____ effects
pleotropic
What are compound heterozygous mutations?
mutations on each allele, but they’re different mutations
What gene mutation causes cystic fibrosis?
CFTR; there’s >1000 disease associated mutations
All mutations are de novo in _________ dysplasia
thanatophoric
What form of HbS polymerizes to form sickle cells?
the deOxy form; this will cause vaso-occlusion
When do patients normally present with sickle cell anemia? Symptoms?
Before age 2; anemia, FTT, splenomegaly, dactylitis (puff hands/feet)
