Inheritance analysis and family history for microtia: A hospital-based study in China

Microtia is a congenital anomaly of the outer ear. Although genetic and environmental factors could play a role, no consensus has been established on the pathogenesis and cause of this condition. In this study, we surveyed the frequency and pattern of family history in patients with microtia in a Chinese specialty clinic population.

We evaluated data from 672 patients (mean age = 9.2, male-to-female ratio = 2.6:1) with microtia admitted to the Department of Auricular Reconstruction at the Plastic Surgery Hospital of Peking Union Medical College from December 2014 to February 2016. Family history of congenital ear anomalies across three generations was recorded. Pearson chi-square test or Fisher exact test was used to test the associations between the characteristics of microtia and hereditary features.

A family history of auricle anomalies was identified in 202 patients (30.1%), of whom, 95 families showed vertical transmission, 14 families skipped a generation, and 120 families showed family aggregations. The incidence of family history varied with grades of microtia (P = 0.001). Patients with preauricular tags or pits (38.3%) had a higher familial incidence of microtia than those with simple microtia (24.1%) (P < 0.001).

Patients with a lower grade of microtia demonstrated a higher incidence of family history. Patients with microtia had significantly more relatives with preauricular tags or pits. Microtia and preauricular tags or pits are different manifestations of the same defect, and their significant concurrency among relatives suggests that a considerable proportion of microtia is inherited and could recur with varying degrees of severity in other family members.