RETROSPECIVE ANALYSIS OF PATIENTS WITH OVERLAPPING FEATURES OF TOWNES-BROCKS SYNDROME AND GOLDENHAR SYNDROME

Abstract

We conducted a retrospective chart analysis of seven patients with expanded spectrum hemifacial microsomia and imperforate anus to determine whether this subset of patients has undiagnosed Townes-Brocks syndrome. Townes-Brocks syndrome is characterized by the triad of imperforate anus, hand and foot anomalies, and ear anomalies. Hemifacial microsomia is not typically a feature of Townes-Brocks syndrome. Expanded spectrum hemifacial microsomia, or Goldenhar syndrome, consists of hemifacial microsomia, ear anomalies, vertebral anomalies, and eye anomalies, including epibulbar dermoids. Although imperforate anus has been reported in Goldenhar syndrome, it is not a common feature. Because these two syndromes have some overlapping features, it is often difficult to differentiate between these two entities in the clinical setting. However, Townes-Brocks syndrome is inherited in an autosomal dominant fashion, whereas Goldenhar is inherited sporadically, thereby emphasizing the importance of distinguishing between these two syndromes. We reviewed the medical records of six patients with expanded spectrum hemifacial microsomia for features of Townes-Brocks syndrome. Our results demonstrate that only one of these six patients could potentially be diagnosed as having Townes-Brocks syndrome. This patient has hemifacial microsomia, bilateral microtia, a left preaxial supernumerary thumb, a right epibulbar dermoid and mild vertebral anomalies. She also has a tethered spinal cord and a hypopastic right kidney. The other five patients had features more consistent with Goldenhar syndrome, VATER association, or other undefined syndromes. We are in the process of characterizing this subset of patients at a molecular level to more accurately predict their genetic risk. This will be done be sequencing the gene that is mutated in Townes-Brocks syndrome, the SALL1 transcription factor, in these patients.