Parents report that their child's face is symmetrically enlarging on both sides of the jaw. What is the most likely diagnosis?

Cherubism is an autosomal dominant fibro-osseous condition caused by mutations in the SH3BP2 gene, characterized by bilateral, symmetrical expansion of the mandible and sometimes the maxilla. It typically presents in childhood (ages 2-5 years) with progressive bilateral jaw enlargement giving the characteristic 'chubby-cheeked' or angelic (cherubic) appearance. Radiographically, there are multilocular radiolucent lesions replacing normal bone. The condition is self-limiting and often stabilizes after puberty, with some spontaneous regression. Fibrous dysplasia (option c) is usually monostotic (unilateral) in children. Cherubism is the classic cause of bilateral, symmetric jaw enlargement in a child.