Any congenital diarrhea in which the cause of the disease is a mutation in the GUCY2C gene. The disease is Monarch Disease Ontology entry MONDO_0013825 (congenital diarrhea 6). Also known as: GUCY2C congenital diarrhea, GUCY2C congenital diarrhoea, chronic diarrhea due to guanylate cyclase 2C overactivity, chronic diarrhoea due to guanylate cyclase 2C overactivity, congenital diarrhea caused by mutation in GUCY2C, congenital diarrhea type 6, congenital diarrhoea caused by mutation in GUCY2C, congenital diarrhoea type 6.