Genetic Analysis by NGS and MLPA in Chinese Aniridia Patients

Abstract

Purpose: To report clinical features and elucidate genetic etiology of patients with congenital aniridia and to reveal the mutational spectrum in the Chinese population. Methods: Sixty patients with congenital aniridia from 51 families were recruited in this study. Candidate genes of developmental eye diseases were captured and analyzed by panel-based next-generation sequencing (NGS), and the mutations were confirmed by polymerase chain reaction (PCR) and Sanger sequencing. Multiplex ligation probe amplification (MLPA)of PAX6 and FOXC1 was performed to detect copy number variations (CNVs) for patients without intragenic mutations. Results: Clinical examinations revealed that 58 patients had complete iris loss, two patients showed partial iris loss. Two patients were diagnosed WAGR syndrome with nephroblastoma. Combining panel-based NGS and MLPA, 43 intragenic mutations or deletions of PAX6, FOXC1, and BCOR genes were identified in 59 patients, including 33 point-mutations (76.7%) in 43 patients and 10 deletions (23.3%) in 16 patients; the total detection rate was 98.3%. Phenotypic variations were observed between families and intra-families. Conclusion: The results confirmed that variations in PAX6 and adjacent regions were the predominant cause of aniridia in China. Besides intragenic point mutations in PAX6, the deletion comprising PAX6 gene or the adjacent genes is also a common cause of congenital aniridia. In addition, FOXC1 gene is another important gene causing congenital aniridia. Panel-based NGS combined with MLPA increase significantly the detection rate of gene mutations for patients with congenital aniridia.