Face, Palate and teeth Flashcards
(13 cards)
Name the components of the Pharyngeal arches
- Mesenchymal core
- External ectodermal lining
- Internal endodermal lining
- Cranial nerve specific to that arch
- Aortic arch artery
What is the mesenchymal core of the Pharyngeal arches made up of
- Paraxial mesoderm
- Lateral plate mesoderm
- Neural crest cells
List some syndromes that arise due to neural crest cell defects
- Treacher collins syndrome
2. DiGeorge anomaly
List some characteristics of treacher collins syndrome
- Down slanting palpebral fissures
- Lower eyelid colhbomas
- Microtia
- Zygomatic and mandibular hypoplasia
- Malformed ossicles
Which pharyngeal arch is most affected by treacher collins syndrome
The 1st pharyngeal arch structures
How is the mandible affected in treacher collins syndrome
Mandibular condyle is most severely affected leading to abnormal TMJ
treacher collins syndrome is a ___________ condition
Genetic
Which gene causes treacher collins syndrome
TOCF1 gene (it is autosomal dominant)
What is the significance of the TOCF1 gene
It encoded a protein called treacle which is expressed in neural folds as neural crest cells are forming and migrating
What are mutations in the TOCF1 gene associated with
Increased apoptosis of neural crest precursors and decreased proliferation of neural crest cells
Give some characteristics of DiGeorge anomaly
- Mild facial malformations such as small mouth, smooth philtrum and micrognathia
- Total/partial agonies of derivatives of the 3rd and 4th pharyngeal pouches
- Cardiac abnormalities
What cardiac abnormalities can arise in DiGeorge anomaly
Tetralogy of fallot
Persistent trunks arteriosus
what causes DiGeorge anomaly
Deletion of chromosome 22 leads to impaired neural crest cell migration
