[Clinical and genetic analysis of two patients with CHARGE syndrome due to de novo variants of CHD7 gene].

OBJECTIVE

To analyze the clinical characteristics and genetic basis of two children patients with CHARGE syndrome.

METHODS

The clinical features of the two patients were analyzed, and potential variants were detected by Trio whole exome sequencing (trio-WES) of the probands and their parents.

RESULTS

Child 1 has manifested cerebellar vermis dysplasia, enlargement of cerebral ventricles, whereas child 2 manifested with infantile spasm and congenital hip dysplasia. Both children were found to harbor de novo heterozygous variants of the CHD7 gene, namely c.4015C>T (exon 17) and c.5050G>A (exon 22). Based on the guidelines of the American College of Medical Genetics and Genomics, the two variants were rated as pathogenic variants, and the related disease was CHARGE syndrome. Furthermore, child 2 was also found to harbor a novel heterozygous c.6161A>C (p.Gln2054Pro) missense variant of COL12A1 gene, which was rated as possibly pathogenic, and the associated disease was Bethlem myopathy type 2, which is partially matched with the patient' s clinical phenotype.

CONCLUSION

The special clinical phenotypes shown by the two children harboring novel CHD7 variants have further expanded the phenotypic spectrum of CHARGE syndrome.