Hemifacial microsomia is a feature of:

 # Hemifacial microsomia is a feature of:

A. Goldenhar syndrome

B. Crouzon syndrome

C. Treacher Collins syndrome

D. Mandibulofacial dysostosis

The correct answer is A. Goldenhar syndrome.

Hemifacial microsomia is a feature of Goldenhar syndrome. Synonyms for hemifacial microsomia include hemifacial hypoplasia, craniofacial microsomia, lateral facial dysplasia, Goldenhar syndrome, and oculoauriculovertebral dysplasia (OAV) spectrum. 

B is incorrect; Hemifacial microsomia is not a feature of Crouzon syndrome. Patients with Crouzon syndrome characteristically have brachycephaly (short skull front to back), hypertelorism (increased distance between eyes), and orbital proptosis (protruding eyes). 

C is incorrect; Hemifacial microsomia is not a feature of Treacher Collins syndrome. The most common clinical findings in Treacher Collins syndrome are relative underdevelopment or absence of the zygomatic bones, resulting in a small narrow face; a downward inclination of the palpebral fissures; underdevelopment of the mandible, resulting in a down-turned, wide mouth; malformation of the external ears; absence of the external auditory canal; and occasional facial clefts. 

D is incorrect, Mandibulofacial dysostosis is a synonym of Treacher Collins syndrome.