An association between hemifacial microsomia and facial clefting.

PURPOSE

Hemifacial microsomia (HFM) is a relatively uncommon malformation, a far second to cleft lip/palate (CL/P). Transverse oral cleft ("macrostomia") is known to be associated with HFM, but there are also reports of concurrent CL/P. We undertook a retrospective study of patients with HFM to document the prevalence of facial clefting. The hypothesis is that the coexistence of facial clefts and HFM suggests a common pathogenic mechanism.

MATERIALS AND METHODS

Records of 198 HFM patients from the database of the Craniofacial Centre at Boston Children's Hospital were reviewed. The age, gender, predominant side of HFM, OMENS classification, and presence, size, and type of cleft (CL/P, transverse oral cleft, or oro-ocular cleft) were documented. We performed chi 2 , t test, and Fishers exact analyses to evaluate the association of facial clefting with HFM.

RESULTS

There were 100 males and 98 females in the HFM study group, with a mean age of 15.3 years (range, 1 to 50 years); 90 were right-sided (45%), 79 were left-sided (40%), and 29 were bilateral (15%). Twenty patients had a CL/P (10%), and of these 15 had unilateral CL/P (UCL/P), equally distributed between right and left sides, and 5 had bilateral CL/P (BCL/P). There were 9 males and 11 females with combined HFM and CL/P. Cleft of the oral commissure (macrostomia) was present in 46 (23.0%) of the HFM patients with a left-to-right-to-bilateral ratio of 5:6:1. There was a significant association between the predominant side of HFM and the side of CL/P ( P < .001) and macrostomia ( P </= .001). We also showed a correlation between the severity of the orbital and mandibular deformities in HFM and the coexisting facial cleft.

CONCLUSIONS

An association implies concurrence, more often than by chance, of 2 or more anomalies and suggests an etiopathologic link. The finding of ipsilateral labial clefts in 10% of HFM patients, and the differing demographic distribution from common labial clefts, suggests an overlapping pathogenesis. Whether the cause is genetic or environmental, we hypothesize that there may be a common pathway leading to a disturbance in neural crest cell migration in HFM patients who also have a facial cleft.