A family with features overlapping Okihiro syndrome, hemifacial microsomia and isolated Duane anomaly caused by a novel SALL4 mutation

Abstract

The SALL4 gene encodes a putative zinc finger transcription factor and is located on chromosome 20q13.13-13.2. Mutations in SALL4 have been identified in patients with Okihiro syndrome, which is characterized by radial ray anomalies associated with a Duane anomaly. Here, we report an unusual family in which affected persons show an extremely variable phenotype consistent with either Okihiro syndrome, hemifacial microsomia, or isolated Duane anomaly. A novel nonsense mutation in the SALL4 gene was detected in all affected family members and obligate carriers. This mutation is located in exon 3, only 29 bp 5' of the most 3' intron, and would therefore be expected to escape the nonsense mediated mRNA decay pathway, which might explain the phenotypic variability and mild degree of limb involvement.