Hypertelorism-microtia-facial clefting syndrome

Hypertelorism-microtia-facial clefting syndrome (also known as HMC syndrome or Bixler syndrome) is an extremely rare congenital malformation syndrome characterized by a distinctive combination of craniofacial anomalies present at birth. The hallmark features include hypertelorism (widely spaced eyes), microtia (underdeveloped or malformed ears), and facial clefting, which may involve cleft lip, cleft palate, or both. Additional features that have been reported in affected individuals include conductive hearing loss related to the ear malformations, renal anomalies, and congenital heart defects, indicating that the syndrome can affect multiple organ systems beyond the craniofacial structures. The condition was first described by Bixler and colleagues, and only a small number of cases have been reported in the medical literature. Some familial cases have been observed, suggesting a genetic basis, though the precise molecular cause has not been definitively established. The pattern of inheritance has been suggested to be autosomal recessive based on reports of affected siblings born to unaffected parents, though this remains to be fully confirmed. Treatment is symptomatic and supportive, focusing on surgical correction of facial clefts, reconstructive surgery for ear malformations, hearing aids or other interventions for hearing loss, and monitoring and management of any associated renal or cardiac anomalies. A multidisciplinary team including craniofacial surgeons, otolaryngologists, audiologists, cardiologists, and nephrologists is typically involved in the care of affected individuals. Genetic counseling is recommended for affected families.

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