Embryology of the Pituitary ✅

Question 1

What is the anterior pituitary derived from?

Answer 1

Ectoderm

Question 2

Which part of the ectoderm is the anterior pituitary derived from?

Answer 2

Rathke’s pouch

Question 3

What is the development of the anterior pituitary originally part of?

Answer 3

Palatal development

Question 4

What does the posterior pituitary derive from?

Answer 4

The neuroectoderm

Question 5

How does Rathke’s pouch develop into the anterior pituitary?

Answer 5

The anterior wall of Rathke’s pouch develops to fill the pouch and form the pars distalis and the pars tuberalis?

Question 6

What does the pars distalis form?

Answer 6

The bulk of the anterior pituitary

Question 7

What occurs in the pars distalis?

Answer 7

Most of the hormone production

Question 8

What does the pars tuberalis form?

Answer 8

A sheath which extends up to the pituitary stalk

Question 9

What is the clinical importance of Rathke’s pouch?

Answer 9

It is from this embryological tissue that a craniopharyngioma is formed

Question 10

What does the posterior wall of the pars distalis form?

Answer 10

The poorly-defined pars intermedia

Question 11

What is the function of the pars intermedia?

Answer 11

It separates the anterior from the posterior pituitary

Question 12

What genetic abnormality is associated with multiple pituitary hormone deficiency?

Answer 12

Mutations of at least 8 genes encoding transcription factors involved in pituitary development

Question 13

Why is it important to identify underlying genetic defects associated with pituitary hormone deficiencies?

Answer 13

To allow the clinician to anticipate likely pituitary hormone deficiencies that will arise and will need monitoring

Question 14

Give 4 genetic mutations that are associated with pituitary hormone deficiencies?

Answer 14

• PROP1
• POU1F1
• HESX1
• LHX3 and LHX4

Question 15

What is the most common genetic mutation associated with pituitary hormone deficiency?

Answer 15

PROP1 gene

Question 16

What is the inheritance of mutations in the PROP1 gene?

Answer 16

Autosomal recessive

Question 17

What are mutations in the PROP1 gene associated with?

Answer 17

Deficiency in GH, TSH, LH, FSH, ACTH, and prolactin

Question 18

What is the inheritance pattern of mutations in POU1F1?

Answer 18

Autosomal dominant or recessive

Question 19

What do mutations of POU1F1 lead to?

Answer 19

Deficiencies of GH, prolactin, and the beta subunit of TSH

Question 20

What is the inheritance pattern of mutations in HESX1?

Answer 20

Autosomal dominant or recessive

Question 21

Where is the HESX1 gene expressed?

Answer 21

In the oral ectoderm that gives rise to Rathke’s pouch

Question 22

What do mutations in HESX1 lead to?

Answer 22

Deficiencies in GH associated with septo-optic dysplasia

Question 23

What is the role of the genes LHX3 and LHX4?

Answer 23

Regulate the proliferation and differentiation of pituitary specific cell lineages

Question 24

What are mutations in LHX3 and LHX4 associated with?

Answer 24

Combined pituitary hormone deficiencies