A novel PITX2 mutation in a Chinese family with Axenfeld-Rieger syndrome

PURPOSE Axenfeld-Rieger syndrome (ARS) is an autosomal dominant disorder characterized by extraocular anomalies and developmental defects of the anterior segment. PITX2 (paired-like homeodomain transcription factor 2) is considered the major causative gene. In this study, we characterized the molecular defect in PITX2 in a Chinese family with ARS. METHODS Two generations of the family with ARS were enrolled in the present study. In addition to ophthalmologic examinations, polymerase chain reaction (PCR) amplification and nucleotide sequencing of all coding exons of PITX2 were performed. Exon 5 (region 1) was also sequenced in 100 healthy controls unrelated to the family for comparison. RESULTS A novel PITX2 mutation, c.840G>T, was identified in all affected members of the family with ARS that causes an amino acid substitution from tryptophan to cysteine at codon 86. CONCLUSIONS We found a novel p.W86C mutation in PITX2 in a Chinese family with ARS. The tryptophan residue at position 86 is strictly conserved in PITX2a proteins from several species and in homeodomain proteins. We suggest that this mutation in PITX2 is the cause of typical ARS in patients. Our results may be useful for better understanding of the spectrum of PITX2 mutations and the role of PITX2 in the development and progression of ARS.