Genetic analysis of the FOXL2 gene using quantitative real-time PCR in Chinese patients with blepharophimosis-ptosis-epicanthus inversus syndrome

PURPOSE The purpose of this study was to identify the mutation(s) or deletion(s) of the forkhead box protein L2 (FOXL2) gene in Chinese patients with blepharophimosis-ptosis-epicanthus inversus syndrome (BPES). METHODS Genomic DNA extracted from peripheral blood was collected from two Chinese families and from one sporadic case. PCR direct sequencing and quantitative real-time PCR-based copy number screening for the whole exon of FOXL2 were performed. RESULTS Direct sequencing revealed an indel mutation c.50C→TA in the sporadic case which resulted in a frameshift generating 78 novel amino acids and terminating prematurely at codon 95. Deletions in the FOXL2 gene were confirmed by quantitative real-time PCR (q-real-time PCR) in two families in which intragenic mutations were excluded by direct sequencing. These changes containing deletions and a de novo mutation were not detected either in the non-carrier relatives or in 100 normal controls. CONCLUSIONS This study identified two deletions and a de novo mutation in the FOXL2 gene in Chinese BPES patients. This is the first study to report FOXL2 gene deletions detected by q-real-time PCR in this ethnic group. This technique enriches the diagnostic methods of molecular genetics in BPES patients. The de novo mutation expands the mutation spectrum of FOXL2.