Defining the clinical spectrum and genotype-phenotype correlations for CCDC115-CDG: A patient report and review of the literature

Abstract

CCDC115-CDG is a recently described combined N- and O-linked congenital disorder of glycosylation affecting Golgi apparatus homeostasis. To date, only thirteen patients have been reported with this condition. The clinical presentation is characterized by hepatosplenomegaly, elevated serum aminotransferases and alkaline phosphatase, often accompanied by psychomotor delay and hypotonia, hypercholesterolemia and copper metabolism anomalies, features that can mimic Wilson disease. Serum transferrin capillary electrophoresis shows a pattern compatible with abnormal Golgi N-glycosylation. We gathered phenotype descriptions and molecular data from all reported patients to better characterize this condition and explore potential genotype-phenotype correlation. Notably, we observed that homozygosity for the p.Leu31Ser variant is associated with higher serum transaminase levels. We also report the natural history of a patient, as clinical narratives are lacking in the literature for this condition. In summary, our report provides new insights into the natural history and genotype-phenotype correlation of CCDC115-CDG, key elements to focus on in ultra-rare conditions.