Microtia and associated anomalies: Statistical analysis

TLDR

Microtia is frequently associated with craniofacial and postcranial anomalies such as oculoauriculovertebral dysplasia, Goldenhar syndrome, hemifacial microsomia, and defects arising from diverse embryonic cell populations. The authors performed statistical analyses on 297 microtia patients with additional anomalies to identify previously described and novel patient subgroups. Analysis revealed 15 distinct anomaly subgroups, with mandibular hypoplasia positively linked to cervical spine fusion and other skeletal anomalies, negatively linked to bilateral microtia, indicating that disturbances in multiple cell populations and the timing of pathogenic events influence the pattern of associated anomalies.

Abstract

Abstract Terms such as oculoauriculovertebral dysplasia, Goldenhar syndrome, and hemifacial microsomia have been used to describe microtia with specific combinations of other craniofacial anomalies. Microtia is also observed with anomalies of postcranial structures. Statistical studies were performed on 297 patients with microtia and other anomalies to identify subgroups of patients representing previously described or new associations. Analysis identified 15 subgroups of patients with specific patterns of anomalies. Log‐linear analyses of cranial and postcranial variables demonstrated a positive association between mandibular hypoplasia and cervical spine fusion, which was, in turn, positively associated with other spine anomalies ( P < .02) and other skeletal anomalies ( P < .001). Although unilateral microtia was commonly observed with mandibular hypoplasia, mandibular hypoplasia was negatively associated with bilateral microtia. Many of the associated anomalies were of structures not derived from the 1st and 2nd branchial arch neural crest. However, most associated anomalies were of structures derived from migratory cell populations or populations undergoing differentiation prior to migration between the 19th and 24th day post‐fertilization (neural crest, ectodermal placode, mesoderm, surface ectoderm). These findings suggest that many different cell populations may be disturbed in the pathogenesis of microtia in association with other anomalies. The timing of the pathogenetic event may determine the specific pattern of associated anomalies.