Phenotypic spectrum of CHARGE syndrome based on clinical characteristics

Abstract

Background/aim: CHARGE syndrome is a rare autosomal dominant disease with multiple congenital anomalies and cognitive impairment, which is caused by mutations in the CHD7 gene. This study aimed to disclose the mild end of the phenotypic spectrum of CHARGE syndrome, which has a highly variable expressivity. Materials and methods: Twenty-one patients who had at least one of the major symptoms of CHARGE syndrome (coloboma, choanal atresia, characteristic ear anomalies, semicircular canal hypoplasia, and cranial nerve anomalies) were included in the study. All patients were tested for karyotype analysis and CHD7 gene mutation/deletion. Results: In the study population, 6 different mutations were detected in 5 patients, and 2 different polymorphisms were detected in the CHD7 gene in 3 patients. MLPA analysis of all coding exons of the CHD7 gene revealed no pathogenic deletion/duplication. Conclusion: CHARGE syndrome should be considered as a differential diagnosis to detect the mild end of the spectrum, even if the patient does not fit the criteria.