177 endo genetics

Question 1

what is the age difference in the presentation of monogenic vs polygenic disease?

Answer 1

monogeneic - early

polygenic - adult

Question 2

klinefelter syndrome

Answer 2

47XXY

long arms/legs

gynecomastia

small testes –> low T; infertilie; osteoporosis (T–> estrogen in bones for protection)

increased LH/FSH (hypergonadatroph hypogonadism) - primary hypogonadism

impaired glucose tolerance

Question 3

normal testes size in adults

Answer 3

18-25 mL

Question 4

Turner Syndrome

Answer 4

45XO

web neck

primary amenorrhea

steak gonads –> infertile + low E –> high LH/FSH

aortic coarctation and bicuspid aortic valve–> aortic stenosis

lymphedema of feet/hands

Question 5

MEN 1

Answer 5

parathryoid adenoma (~ 25 years, younger, x4)
pituitary adenoma
pancreases tumor

AD with 2nd hit concept

Menin gene on 11q13 –> tumor supressor

Question 6

MEN 2

Answer 6

AD - GOF tyrosine kinase RET

MEN 2A - extracellular
MEN 2B - intracellular
high genotype-pheotype relationship

Question 7

hereitary pheochromocytoma

Answer 7

good example of locus heterogenity

MEN 2
VHL
NF1
SDH –> pheo + paraganglioma

should offer pheo patients genetic testing

Question 8

CAH

Answer 8

inborn error of steroid synthesis

AR - heterozygotes may have mild phenotype

increases ACTH because cortisol low

Question 9

androgen resistance

Answer 9

5a reductase converts to DHT

mutation androgen receptor on X chromosome

46XY but phenotype female –> amenorrhea

abdominal testes

Question 10

Reifenstein syndrome

Answer 10

genetic male

partial androgen resistance

Question 11

DM

Answer 11

monogenic (AD - maturity onsent diabetes of the young - MODY) and DM 2 (multifactorial)

Question 12

locus heterogenecity

Answer 12

different genes cause the same phenotype

congenital hypothroidism is a good example

Question 13

allelic heterogeneity

Answer 13

one gene can cause many different phenotypes

different mutations in same gene