Objective: This paper compares demographic, morphological, functional, and risk factors between isolated and familial forms of microtia in Ecuadorian mestizo patients. Methods: The authors did an epidemiological, and retrospective study with 112 patients divided into isolated microtia (n = 91) and familial microtia (n = 21). Patients with syndromic microtia were not included. Results: In isolated microtia, the mean age was 11.80 ± 16.9, and the most prevalent age group was from 5 to 9 years, with 45.0%; males were 58.2%, and 91.2% of patients were born in a city above 2500 meters about sea level. In familial microtia, the mean age was 15.57 ± 17.2. There were no statistically significant differences between the analyzed variables. In isolated microtia, 41.8% of patients had bilateral involvement, 40.7% had grade 1 microtia in the right ear (RE), and grade 1 in the left ear was 47.3%; external auditory canal atresia of RE was present in 62.6%, and in left ear in 31.6%. External auditory canal atresia sidedness was mostly unilateral in both groups. Most patients did not have tags or pits (78% and 81% in RE and 85.7% and 71.4%). Most patients had moderate hearing loss in both ears. Conclusion: The authors found an association between both microtia forms with external auditory canal atresia in RE; only 20% of patients had unilateral auricular tags or pits in both groups. The authors also found a high incidence (18.75%) of familial microtia, which suggests a distinct pathological genetic component than the more prevalent isolated cases. The authors found a high association of microtia cases from the Ecuadorian highlands above 2500 meters about sea level (over 90%). The presence of “social” intake of alcohol during pregnancy showed over twice the chance of having a child born with microtia.
