Auriculocondylar syndrome

Auriculocondylar syndrome (ACS), also known as question mark ear syndrome or dysgnathia complex, is a rare craniofacial disorder primarily affecting the development of the first and second pharyngeal arches during embryonic development. The condition is characterized by distinctive ear malformations — most notably a cleft between the lobule and the helix that gives the ear a 'question mark' appearance — along with mandibular condyle hypoplasia or aplasia, which leads to significant underdevelopment of the lower jaw (micrognathia). Additional features may include prominent cheeks, a small mouth (microstomia), abnormal temporomandibular joint function, glossoptosis (posterior displacement of the tongue), feeding difficulties, and respiratory problems in infancy due to airway compromise from the mandibular hypoplasia. Hearing loss, preauricular tags, and cleft palate may also occur. The severity of clinical features is highly variable, even within the same family. Auriculocondylar syndrome is caused by pathogenic variants in the GNAI3, PLCB4, or EDN1 genes, all of which play roles in the endothelin signaling pathway critical for craniofacial development. Both autosomal dominant and autosomal recessive inheritance patterns have been described depending on the gene involved. There is no cure for ACS, and management is supportive and symptom-based. Treatment may include surgical correction of jaw and ear anomalies, orthodontic interventions, management of airway obstruction (which may require tracheostomy in severe cases), speech therapy, and hearing aids if hearing loss is present. A multidisciplinary team involving craniofacial surgeons, otolaryngologists, audiologists, and speech-language pathologists is typically needed for optimal care. Long-term follow-up is important as mandibular growth may be progressively affected.

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