Embryology of the Pituitary ✅ Flashcards
(24 cards)
What is the anterior pituitary derived from?
Ectoderm
Which part of the ectoderm is the anterior pituitary derived from?
Rathke’s pouch
What is the development of the anterior pituitary originally part of?
Palatal development
What does the posterior pituitary derive from?
The neuroectoderm
How does Rathke’s pouch develop into the anterior pituitary?
The anterior wall of Rathke’s pouch develops to fill the pouch and form the pars distalis and the pars tuberalis?
What does the pars distalis form?
The bulk of the anterior pituitary
What occurs in the pars distalis?
Most of the hormone production
What does the pars tuberalis form?
A sheath which extends up to the pituitary stalk
What is the clinical importance of Rathke’s pouch?
It is from this embryological tissue that a craniopharyngioma is formed
What does the posterior wall of the pars distalis form?
The poorly-defined pars intermedia
What is the function of the pars intermedia?
It separates the anterior from the posterior pituitary
What genetic abnormality is associated with multiple pituitary hormone deficiency?
Mutations of at least 8 genes encoding transcription factors involved in pituitary development
Why is it important to identify underlying genetic defects associated with pituitary hormone deficiencies?
To allow the clinician to anticipate likely pituitary hormone deficiencies that will arise and will need monitoring
Give 4 genetic mutations that are associated with pituitary hormone deficiencies?
- PROP1
- POU1F1
- HESX1
- LHX3 and LHX4
What is the most common genetic mutation associated with pituitary hormone deficiency?
PROP1 gene
What is the inheritance of mutations in the PROP1 gene?
Autosomal recessive
What are mutations in the PROP1 gene associated with?
Deficiency in GH, TSH, LH, FSH, ACTH, and prolactin
What is the inheritance pattern of mutations in POU1F1?
Autosomal dominant or recessive
What do mutations of POU1F1 lead to?
Deficiencies of GH, prolactin, and the beta subunit of TSH
What is the inheritance pattern of mutations in HESX1?
Autosomal dominant or recessive
Where is the HESX1 gene expressed?
In the oral ectoderm that gives rise to Rathke’s pouch
What do mutations in HESX1 lead to?
Deficiencies in GH associated with septo-optic dysplasia
What is the role of the genes LHX3 and LHX4?
Regulate the proliferation and differentiation of pituitary specific cell lineages
What are mutations in LHX3 and LHX4 associated with?
Combined pituitary hormone deficiencies
