04a: Growth, Gender

Question 1

Postnatal growth velocity (increases/declines) progressively until (X) years old, when it becomes constant at (Y)/year until onset of puberty.

Answer 1

Declines (25cm, 12 cm, 8 cm/y)
X = 3
Y = 4.5 cm

Question 2

“Short stature” is defined by which characteristics?

Answer 2

1. Height more than 2 SD below mean for age/sex OR

2. Below 3rd percentile for age/sex

Question 3

Mid-parental height for F equation

Answer 3

(mom’s height + father’s height-13 cm)/2

Question 4

Mid-parental height for M equation

Answer 4

(mom’s height+13 cm + father’s height)/2

Question 5

T/F: Most conditions that cause poor linear growth also cause delay in skeletal maturation (retarded bone age).

Answer 5

True (malnutrition, hypothyroid, GH deficiency)

Question 6

Your M patient has slow growth rates and a family Hx of delayed puberty/growth spurt. If you wanted to estimate his bone age, what chart/value might you use?

Answer 6

Height age - age at which the patient’s height would fall into 50th percentile

(patient likely has constitutional delay of growth)

Question 7

Any (M/F) who presents with unexplained (X), esp (with/without) fam Hx of (X), should be tested for Turner syndrome.

Answer 7

F
X = short stature
Without

Question 8

Preserved weight gain or frank obesity associated with poor linear growth suggests an (systemic illness/endocrine disorder).

Answer 8

Endocrine disorder;

decreased weight-to-height ratio generally indicates a systemic illness

Question 9

GH receptor (GHR) has (intracellular/extracellular/transmembrane) domain(s) and exists as (monomer/dimer/pentamer).

Answer 9

All 3

Dimer

Question 10

T/F: One GH molecule binds one GHR active site on extracellular domain.

Answer 10

False - one GH binds two GHR

Question 11

T/F: GH binds GHR causes conformational change in receptor and autophosphorylation.

Answer 11

False - no intrinsic kinase activity in GHR; instead, recruit/transphosphorylate JAK2

Question 12

GH binding GHR causes conformational change and (activation/inhibition) of (X), which then causes (activation/inhibition) of (Y).

Answer 12

Activation (via transphosphorylation)
X = JAK2 (tyrosine kinase)
Activation (phosphorylation)
Y = STAT5b (signal transducers and activators of transcription)

Question 13

JAK2 phosphorylates tyrosines on intracellular domain of (X) receptor, which serves as docking site for STAT5b. What happens next?

Answer 13

X = GH

Phosphorylates STAT5b; STAT5b dissociate from R, dimerize, go to nucleus, bind DNA, initiate IGF-1 gene transcription

Question 14

Assessing GH deficiency: levels of (X) are useful because their concentrations parallel (Y).

Answer 14

X = IGF-1 and IGF BP-3 (major carrier for IGF-1)
Y = secretion of GH

Question 15

T/F: GH levels are not used to assess GH deficiency because they cannot be measured in the serum.

Answer 15

False - can be, but not useful; secreted in pulsatile manner and serum levels are low between pulses

Question 16

Your pre-pubertal male patient tells you he thinks he sometimes identifies as female. His uncertainty makes you reluctant to start hormone therapy. What step could you take at this point to help him/her?

Answer 16

Give him/her time;

GnRH analog will delay puberty in reversible fashion

Question 17

F to M transgender hormone Rx:

Answer 17

Testosterone (doses similar to those used for hypogonadal males)

Question 18

M to F transgender hormone Rx:

Answer 18

1. Anti-androgen (spironolactone is drug of choice in US)

2. Estrogen supplementation

Question 19

At (higher/lower) doses, (X) BP med is used as hormone Rx for (M/F) to (M/F) transition.

Answer 19

Higher (up to 200 mg/day);
X = spironolactone
M to F

Question 20

Which estrogen supplementation options exist for M to F transgender patients?

Answer 20

1. Permarin (conjugated estrogens)

2. Estradiol

Question 21

Biggest concerns for F to M transgender hormone Rx

Answer 21

1. Increased Hct (thrombosis risk)
2. Decreased HDL (CAD risk)
3. More aggressive?
4. Sleep apnea

Question 22

T/F: There are no real health concerns in M to F transition, compared to F to M transition.

Answer 22

True - maybe decreased libido? Be sure to screen prostate and developing breasts for cancer