medical genetics (1) Flashcards
what are the 5 subdivisions of medical genetics?
- clinical
- genetic counseling
- molecular genetics
- biochemical genetics
- cytogenetics
which subdivision of medical genetics is the following describing
“ deals with the diagnosis, treatment & research of inborn errors of metabolism”
biochemical genetics
what enzyme is mutated in albinism?
tyrosine oxidase
list some general characteristics of inborn errors of metabolism
- single enzyme defect
- recessive
- challenge to detect the particular substance & pathway involved
- general clinical features
- poor growth, mental retardation, problems with metabolism, neuro problems
what is the name of the group of disorders caused by defects in BH4 metabolism?
hyperphenylalaninemias
what enzyme is deficient in classical PKU?
phenylalanine hydroxylase
describe how non pku hyperphenylalanemia is diff from classical pku
in non pku-has 10x increase in phen levels (which is MUCH less than what you see in full pku), less damaging, may be benign, may not require special diet
what term describes the association of classical pku, varient pku and non pku hyperphenylalanimia?
clinical heterogeneity: diff phenotypes from mutation of single gene
define clinical heterogenity
diff phenotypes from mutation of single gene
what is the term used to describe the disease that has a deficiency in DHRP enzyme in comparison to PKU disease?
locus heterogeneity (mutations in diff genes lead to SAME clinical phenotype).
what are lysosomal storage diseases?
mutation of a lysosomal hydrolytic enzymes leads to the failure of degradation and the accumulation of macromolecules in lysosomes
list some characteristics of tay sachs disease. what builds up?
- Autosomal recessive & rare except in Ashkenazi jews
- death 2-4 years very progressive disease
- Deficiency of hexosaminidase A
- Inability to degrade GM2 ganglioside so build up in the brain
with what disease do you see the “cherry red spot” on the retina?
tay sach’s disease
what cannot be degraded in a person with mucopolysaccharidoses?
can’t degrade glycosaminoglycans
list some clinical presentations of mucopolysaccharidoses
short stature, delay, skeletal abnormalities and joint stiffness, thickened skin, heart liver or spleen damage
what type of inheritance pattern does the following describe:
“-a subset of cells in an individual that arose by clonal propagation from a single mutation in one cell
-a cell can get a mutation..proliferate/create a clone and cause a disease”
acquired gene complement
what disease does the following describe:
“due to mutations in type 1 collagen with either reduced collagen production or defective collagen”
osteogensis imperfecta
what disease does the following describe:
“Error in post translational modification of collagen”
ehler-danlos
what disease has the following clinical presentations?
“Skin fragility, joint hypermobility, skin hyperextensibility”
ehler danlos disease
what are two primary genes were mutations are often seen in ehler danlos disease?
COL5A
COL3A
what disease does the following describe
“connective tissue disorder
mutation in the fibrillin gene”
marfans
what are the primary targets in marfan’s disease
skeleton, eyes (dislocated lenses and myopia), heart (aorta can get very thin and not a strong and eventually rupture)
