Craniofacial disorders Flashcards
When does craniofacial development occur?
4-10 weeks in utero
What causes organ disorders?
Impairment of early embryonic developmental processes like morphogenesis.
What factors can cause craniofacial disorders?
Genetic (mutations in developmental genes) or environmental (teratogens)
How are craniofacial disorders classified by phenotype?
Syndromic - defects occur along with other anomalies
Non-Syndromic - defects don’t occur with other anomolies
How do the genes that syndromic and non-syndromic disorders affect differ?
Syndromic - affects genes that have multiple functions in developmental process of other organs.
Non-Syndromic - affects genes that can be compensated by others in different genes or the organ was more sensitive to gene dosage.
How are craniofacial disorders classified by developmental timing?
Early defects affect development e.g. cleft lip, abnormal number of teeth
Late defects affect cell differentiation e.g. abnormal eruption dates
How does combinatorial cell signalling form new genetic programmes?
Combinations of TF regulate the expression of a cell signalling molecule. it is released and binds to a receptor on a target cell. the signal is integrated and received, resulting int he activation of other TF that bind to regulatory region and regulate the expression of a new gene.
Where are craniofacial structures derived from?
Pharyngeal arches.
Pharyngeal arch 1 = mandible and maxilla and teeth
What are CNCs
Cranial neural crest cells
They migrate from the early brain into a specific pharyngeal arch and form the majority of craniofacial structures .
Is a cleft lip syndromic or non-syndromic?
70% are non-syndromic, 30% syndromic
different types with different severity
What is Treacher Collins syndrome and what causes it?
It is hypoplasia of the mandible and facial bones.
Caused by apoptosis of CNCs
What is craniosynostosis?
Premature fusion of cranial sutures
How will the tooth be effected if it development is impaired early?
Tooth numbers and identity will be affected
How will the tooth be effected if its development id impaired during morphogenesis?
Tooth she and size will be effected
How will the tooth be effected if its development is impaired late?
Differentiation will be effects - hard tissues will be impaired.
