Atypical CHARGE associated with a novel frameshift mutation of CHD7 in a Chinese neonatal patient

Abstract

Background: CHARGE syndrome is an autosomal dominant malformation disorder caused by heterozygous loss of function mutations in the chromatin remodeler CHD7, which has been estimated to occur in 1:10,000 births worldwide. It is a genetic disorder closely resembles other pattern of anomalies. Genetic testing should be pointed out as a useful method for clinical diagnosis. Case presentation: A female infant was the second child born to a 33-year-old, gravida 3, para 2 mother. The infant was born at 37 + 4 weeks of gestation with a birth weight of 2440 g (-1.1 S.D.). Clinical examination showed atypical CHARGE syndrome, with choanal atresia, a heart defect, and sensorineural deafness. Genomic DNA was extracted from peripheral venous blood sample using molecular biological technique. We used the Illumina TruSigt One sequencing panel on the MiSeq next- generation sequencing (NGS) platform for mutation screening and found a novel frameshift mutation in chromodomain helicase DNA binding protein 7 (CHD7; c.4656dupT). This mutation results in a new reading frame ending in p.(Ile1553fs). At the first month of age, the patient had a posterior nostril plasty operation by nasal endoscope. At the second month of age, she had patent ductus arteriosus ligation surgery. At the 4th month of age, she was discharged from the hospital. Conclusions: Our findings further reveal that patients should not be rejected for CHD7 mutational analysis even if they do not fulfill CHARGE syndrome Verloes criteria.