Flashcards on Congenital Craniofacial Clefts: Etiology and Treatment
Congenital Craniofacial Clefts: Etiology & Treatment Guide
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Craniofacial clefts overview
88 cards
Card 1
Question: What is the estimated incidence range of craniofacial clefts in live births?
Answer: Approximately 1.4–4.9 per 100,000 live births.
Card 2
Question: How does the incidence of rare craniofacial clefts compare to common cleft lip and palate malformations?
Answer: Rare craniofacial clefts range from about 9.5 to 34 per 1,000 compared to common cleft lip and palate (note: this reflects rates cited in the content
Card 3
Question: Are most rare craniofacial clefts familial or sporadic?
Answer: Most rare craniofacial clefts occur sporadically, though some familial cases exist.
Card 4
Question: Which syndromes mentioned show a hereditary role in rare craniofacial clefts?
Answer: Treacher–Collins syndrome and some familial cases of Goldenhar syndrome.
Card 5
Question: What gene defect causes Treacher–Collins syndrome and what is notable about its penetrance?
Answer: A dominant defect in the TCOF-1 gene causes Treacher–Collins syndrome; penetrance is somewhat variable but the malformation is very consistent.
Card 6
Question: What embryologic process was disrupted in the TCOF-1 knock-out animal model, and what facial abnormality resulted?
Answer: Massive regional cell death affected neural crest (crest cell mesenchymal) migration, resulting in zygomatic abnormalities.
Card 7
Question: What limb condition has been associated with rare facial clefting, and what study found this association?
Answer: Constriction limb deformities (amniotic band syndrome) have been associated; Coady et al. found a statistically significant association between cranio
Card 8
Question: What four major environmental categories have been shown to cause facial clefts in animal and human studies?
Answer: (1) Radiation, (2) infection, (3) maternal metabolic imbalances, and (4) drugs and chemicals.
Card 9
Question: Which class of medications is noted as being investigated for causing facial malformations?
Answer: Medications containing retinoic acid are being investigated as potential causes of facial malformations.
Card 10
Question: Why is determining the teratogenic cause of a specific facial cleft difficult?
Answer: Because multiple factors can act on numerous developmental pathways, and the critical embryologic phase often occurs before a mother knows she is preg