Endocrine disorders of growth + development

Question 1

When does child need further growth assessment

Answer 1

Where weight or height or BMI is below the 0.4th centile
If height centile more than 3 centile spaces below mid-parental centile
Drop in height centile position of 2 centile spaces +

Question 2

Disproportionate growth failure

Answer 2

Skeletal dysplasia

–> achondroplasia, hypochondroplasia, Leri-Weill dyschonrosteosis, Rickets

Question 3

Height standard deviation score

Answer 3

(Measurement-mean)/SD at relevant age

Question 4

Classifications of limb shortening

Answer 4

Rhizomelic
Mesomelic
Acromelic

Question 5

Achondroplasia

Answer 5

Lack of ossification at growth plates
Lack of long bone elongation
FGFR3 mutations
Autosomal dominant
Nucleotide 1138 resulting from either G>A or G>C

Question 6

Hypochondroplasia

Answer 6

FGFR3 mutation, other than the 1138 position
Affects structure + function of receptor
Features milder than achondroplasia
Short stature noticed later

Question 7

Leri-Weill Dyschonrosteosis (LWD)

Answer 7

AD skeletal dysplasia
Mesomelic (mid parts) limb shortening
Reduced subischial length
Madelung deformity of forearm–> boing of radius, dorsal ulna dislocation, premature epiphyseal fusion

Question 8

Short stature

Answer 8

SHOX Haploinsufficiency is most important monogenic cause of Short Stature
Wide phenotypic variability (ISS–>LWD)

Question 9

Turner Syndrome

Answer 9

Short
SHOX haploinsufficiency
Gonadal dysgenesis
Webbed neck
Shield chest, widely spaced nipples
Cubitus valgus
Lymphoedema of hands
Shortening 4th/5th metacarpal
Knock-knees

Question 10

GH released from

Answer 10

Somatotroph cell in pituitary
Pulsatile secretion
GH pulses secreted every 3-4hours

Question 11

GH-IGF1 axis

Answer 11

GH stimulates IGF1 production in liver and other target tissues
IGF1 stimulates IGF1 receptor in target tissues + growth plates
–> GROWTH

Question 12

GH deficiency

Answer 12

Isolated or part of panhypopituitarism

Associated genes- GH1, GHRHR, BTK

Question 13

Laron Syndrome

Answer 13

GH insensitivity
Normal size at birth
Severe growth restriction in infancy
Distinctive facial features
Blue sclerae
Hypoglycaemia - insulin sensitivity

Question 14

Height-promoting treatments

Answer 14

GH
Oxandrolone
Somatropin

Question 15

First markers onset puberty

Answer 15

Girls: 8-13 years, breast development, pubic hair
Boys: 9.5-14 years, genital development + pubic hair

Question 16

Tanner stage B2- girls

Answer 16

First physical marker of puberty

BUT may be present without central activation of HPG axis

Question 17

Central puberty indication- males

Answer 17

Testicular volume >3cc

–> most will have further increase in testicular volume when re-examined 6 months later