medical genetics (1)

Question 1

what are the 5 subdivisions of medical genetics?

Answer 1

1. clinical
2. genetic counseling
3. molecular genetics
4. biochemical genetics
5. cytogenetics

Question 2

which subdivision of medical genetics is the following describing
“ deals with the diagnosis, treatment & research of inborn errors of metabolism”

Answer 2

biochemical genetics

Question 3

what enzyme is mutated in albinism?

Answer 3

tyrosine oxidase

Question 4

list some general characteristics of inborn errors of metabolism

Answer 4

• single enzyme defect
• recessive
• challenge to detect the particular substance & pathway involved
• general clinical features
• poor growth, mental retardation, problems with metabolism, neuro problems

Question 5

what is the name of the group of disorders caused by defects in BH4 metabolism?

Answer 5

hyperphenylalaninemias

Question 6

what enzyme is deficient in classical PKU?

Answer 6

phenylalanine hydroxylase

Question 7

describe how non pku hyperphenylalanemia is diff from classical pku

Answer 7

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

Question 8

what term describes the association of classical pku, varient pku and non pku hyperphenylalanimia?

Answer 8

clinical heterogeneity: diff phenotypes from mutation of single gene

Question 9

define clinical heterogenity

Answer 9

diff phenotypes from mutation of single gene

Question 10

what is the term used to describe the disease that has a deficiency in DHRP enzyme in comparison to PKU disease?

Answer 10

locus heterogeneity (mutations in diff genes lead to SAME clinical phenotype).

Question 11

what are lysosomal storage diseases?

Answer 11

mutation of a lysosomal hydrolytic enzymes leads to the failure of degradation and the accumulation of macromolecules in lysosomes

Question 12

list some characteristics of tay sachs disease. what builds up?

Answer 12

• 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

Question 13

with what disease do you see the “cherry red spot” on the retina?

Answer 13

tay sach’s disease

Question 14

what cannot be degraded in a person with mucopolysaccharidoses?

Answer 14

can’t degrade glycosaminoglycans

Question 15

list some clinical presentations of mucopolysaccharidoses

Answer 15

short stature, delay, skeletal abnormalities and joint stiffness, thickened skin, heart liver or spleen damage

Question 16

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”

Answer 16

acquired gene complement

Question 17

what disease does the following describe:

“due to mutations in type 1 collagen with either reduced collagen production or defective collagen”

Answer 17

osteogensis imperfecta

Question 18

what disease does the following describe:

“Error in post translational modification of collagen”

Answer 18

ehler-danlos

Question 19

what disease has the following clinical presentations?

“Skin fragility, joint hypermobility, skin hyperextensibility”

Answer 19

ehler danlos disease

Question 20

what are two primary genes were mutations are often seen in ehler danlos disease?

Answer 20

COL5A

COL3A

Question 21

what disease does the following describe
“connective tissue disorder
mutation in the fibrillin gene”

Answer 21

marfans

Question 22

what are the primary targets in marfan’s disease

Answer 22

skeleton, eyes (dislocated lenses and myopia), heart (aorta can get very thin and not a strong and eventually rupture)