Partial CHARGE syndrome with bilateral retinochoroidal colobomas associated with 7q11.23 duplication syndrome: case report

BACKGROUND: CHARGE syndrome is a relatively common cause of deafness and blindness resulting from failure to form the primordia of specific organs due to deficient contribution of neural crest cell derivatives. The majority of CHARGE syndrome cases are caused by heterozygous mutations in CHD7 on chromosome 8q21. Those with CHARGE syndrome without CHD7 mutation typically do not have an identified genetic defect. 7q11.23 duplication syndrome is associated with mild facial dysmorphism, heart defects, language delay, and autism spectrum disorder. In the current literature, 7q11.23 duplication has not been associated with CHARGE syndrome, retinochoroidal colobomas, or significant ear abnormalities. CASE PRESENTATION: We describe a patient with 7q11.23 duplication syndrome and clinical CHARGE syndrome with no variant in CHARGE-associated genes. CONCLUSIONS: This case highlights the still incomplete understanding of the pathogenesis of CHARGE syndrome and raises the possibility of a dose-sensitive effect of genes in the 7q11.23 critical region on neural crest differentiation and fate.