Linking human syndromes to molecular processes Flashcards
What are the two types of congenital anomalies affecting the craniofacial region?
Isolated = one defect
Syndromic = many physical signs and symptoms occurring together
What are the 4 types of cleft issues?
Isolated cleft palate
Unilateral cleft palate and lip
Bilateral cleft palate and lip
Cleft lip
What is the most common type of cleft?
Unilateral cleft lip and palate
Why do we use an antenatal screening programme for Down syndrome?
This identifies a women in whom a risk of Down syndrome is sufficiently high risk of Down syndrome.
What is a teratogen?
Any agent that causes a structural abnormality following fatal exposure during pregnancy e.g. alcohol, mercury, cocaine.
What are ways in which we may be able to treat craniofacial deformity in the future?
Stem cells
Early diagnosis
Therapeutic intervention
What can cleft lip cause for the teeth?
Malocclusions Class 3 reverse bite Reverse incisors relations Narrow maxillary arch Lots of crowding
How does the palate usually form?
Shelves of forming palate grow towards each other and meet in the midline during development.
They then fuse together at they midline.
FGF receptor 2b is expressed in one part of the palatal shelf and this signals to Fgf10.
Knocking either of these genes out will give the mouse a cleft palate.
Due to the failure of the palatine shelves fusing.
What signalling pathway causes proliferation of palatal cells?
Proliferation of the cells for the proliferation of palatal cells.
FGF10 binds to its receptor and switches on FGfr2b induced proliferation of the mesenchymal cells.
What is craniosyntosis?
Premature fusion of one of a number of sutures within the skull vault.
This means the brain will then expand in any direction which the skull allows it to.
What balance is needed for sutures to form?
Sutures maintain a balance of bony formation and proliferation of mesenchymal cells.
Too much bone formation causes the suture to cure prematurely.
Not enough = large open gaps within the skull.
(FGF ligands binds to the receptor and casues a signal.
In a mutation, there is excess signalling that occurs.
This causes prolonged bone formation.)
What is Treacher Collins syndrome?
Defect during the 1st and 2nd brachial arch development.
Major defects in the external ear.
Hereditary condition.
The gene inside of the ribosome considered important.
The gene gets expressed in the phayngeal folds and the frotontonasal processes in these affected individuals.
Problems in the neural crest cells as the formation of ribosomes doesn’t work.
This causes increased cell death of neural crest cells so no growth in the maxillary and mandibular processes.
Why is hedgehog signalling important?
Important signalling molecule in development required fro growth, pattering and morphogenesis in all parts of the embryo.
Important in regulating post natal development also.
