Physiology & Biochemistry · single question
What is the pattern of inheritance of Cleidocranial Dysplasia?
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Correct answer: A. Autosomal Dominant
✓ A) Autosomal Dominant is correct.
Cleidocranial Dysplasia (CCD) is caused by mutations in the RUNX2 gene and follows an autosomal dominant inheritance pattern (though 1/3 of cases are de novo mutations). Features include: absent/hypoplastic clavicles (allowing shoulder approximation), open fontanelles, supernumerary teeth, delayed eruption, short stature. The dental implications are significant — multiple retained primary teeth and impacted supernumerary teeth require extensive management.
Cleidocranial Dysplasia (CCD) is caused by mutations in the RUNX2 gene and follows an autosomal dominant inheritance pattern (though 1/3 of cases are de novo mutations). Features include: absent/hypoplastic clavicles (allowing shoulder approximation), open fontanelles, supernumerary teeth, delayed eruption, short stature. The dental implications are significant — multiple retained primary teeth and impacted supernumerary teeth require extensive management.
- A. While de novo mutations occur in ~one-third of cases, CCD IS autosomal dominant and CAN be inherited from an affected parent.
- B. Cleidocranial dysplasia (CCD) is an AUTOSOMAL DOMINANT condition caused by mutations in RUNX2 (CBFA1) gene. Key features: absent or hypoplastic clavicles (the defining feature — allows patient to approximate shoulders), delayed closure of fontanelles, supernumerary teeth, delayed eruption, frontal bossing, midface hypoplasia. As autosomal dominant, a parent with CCD has a 50% chance of passing it to each child.
- C. CCD is NOT autosomal recessive — it is autosomal dominant with high penetrance.
- D. CCD is NOT X-linked — it is autosomal (chromosome 6) dominant.
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