Genetic analysis of the CHD7 gene in Korean patients with CHARGE syndrome

Abstract

CHARGE syndrome is an autosomal dominant congenital disorder known to be caused by the haploinsufficiency of the CHD7 gene. Heterozygous mutations in the CHD7 gene have been identified in approximately 60-70% of patients clinically diagnosed with CHARGE syndrome. Although there have been many reports on the mutational spectrum of the CHD7 gene in patients with CHARGE syndrome worldwide, little is known about this syndrome in the Korean population. In this study, three Korean patients with CHARGE syndrome including one patient with Patau syndrome were evaluated for genetic analysis of the CHD7 gene using direct sequencing of all 38 exons and the flanking intronic regions. One nonsense and two novel missense mutations were identified in the CHD7 gene. Clinical symptoms caused by the missense mutations were much milder compared to the nonsense mutation, confirming the previously determined genotype-phenotype correlation in CHARGE syndrome. Our study demonstrates the importance of mutational screening of CHD7 in patients who have been diagnosed with other syndromes but display clinical features of CHARGE syndrome.