Gorlin Syndrome Inheritance — ORE Part 1 MCQ

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ModerateOral PathologyGorlin Syndrome InheritanceORE Part 1

A 20-year-old man presents with multiple keratocystic odontogenic tumours (odontogenic keratocysts) in both jaws. He also has multiple basal cell carcinomas on his skin and calcification of the falx cerebri on skull radiograph. What is the inheritance pattern of this condition?

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Correct answer: A — Autosomal dominant

Explanation lettering: E = shown as B · D = shown as C · B = shown as D · C = shown as E

This clinical presentation is pathognomonic for Gorlin syndrome (Nevoid Basal Cell Carcinoma Syndrome/Gorlin-Goltz syndrome): the triad of multiple odontogenic keratocysts, multiple basal cell carcinomas, and falx cerebri calcification. Gorlin syndrome is inherited in an autosomal dominant pattern with high penetrance and variable expressivity. The condition results from germline mutations in the PTCH1 tumour suppressor gene (chromosome 9q22.3) in 50–85% of cases, or less commonly in SUFU or PTCH2. Patients have a 50% chance of inheriting and expressing the condition. Option B (autosomal recessive) would require two mutated copies and typically presents more severely in childhood; Gorlin syndrome is not recessive. Options C, D, and E (X-linked and mitochondrial) are inconsistent with the known molecular genetics of the condition.

Reference: Gorlin syndrome: a case report. PubMed 2005 (https://pubmed.ncbi.nlm.nih.gov/16327143/); Identification of a SUFU germline mutation in a family with Gorlin syndrome. PubMed 2009 (https://pubmed.ncbi.nlm.nih.gov/19533801/)