Endocrine Disorders of Development and Growth

Question 1

What is mid-parental height?

Answer 1

When you see the centile of dad’s height and of mother’s to work out if the child is normal but small or if there is a disorder of growth.

Question 2

What is the normal height growth velocity?

Answer 2

10cm/year

Question 3

What general tests are done to investigate growth problems?

Answer 3

FBCs (checking for anaemia)
U&Es (to test kidney function)
Liver function tests
Bone profile (to check parathyroid and bones)
Vitamin D (to check parathyroid, bones, calcium)
ESR and CRP
Total immunoglobulins
Coeliac screen

Question 4

What endocrine tests are done to investigate growth problems?

Answer 4

Thyroid function tests
IGF-1
Growth hormone
Prolactin
Gonadotrophins
Random cortisol
Bone age (delayed or accelerated?)
Karyotype in girls (to check for Turner syndrome)

Question 5

What is seen in growth hormone insensitivity?

Answer 5

Severe short stature
Normal/elevated GH
Low IGF-1

Question 6

How is growth hormone insensitivity treated?

Answer 6

Synthetic IGF-1

Question 7

What are the adverse effects of synthetic IGF-1?

Answer 7

Tonsillar hypertrophy

Hypoglycaemia

Question 8

Are children shorter if they have GH insensitivity or GH deficiency?

Answer 8

Insensitivity

Question 9

How is GH deficiency treated?

Answer 9

GH

Question 10

What is Turner syndrome?

Answer 10

Missing X chromosome in females

Question 11

What is Klinefelter syndrome?

Answer 11

Extra X chromosomes (2 or more) in males

Question 12

What is Kallman syndrome?

Answer 12

Failure to start or complete puberty (failure of hypothalamus to release GnRH at the appropriate time)

Question 13

Are exons or introns coding DNA?

Answer 13

Exons (introns are ‘junk’ DNA)

Question 14

Explain the GH-IGF-1 axis.

Answer 14

• The hypothalamus commands the pituitary gland through somatostatin and GHRH
• Pituitary produces GH
• GH travels to liver and other organs – it attaches to the cell and dimerises the GH receptor.
• Production of IGF-1
• IGF-1 is quite unstable, so it needs IGFBP-3 and ALS

Question 15

What mutations may disrupt the GH-IGF-1 system?

Answer 15

Mutations in ALS or IGF-1 etc…

These cause the system to fall apart.