DDOST-Congenital Disorder of Glycosylation: Defining the Clinical Spectrum and First Report of a Structural Variant

Congenital disorders of glycosylation (CDG) are a heterogeneous group of metabolic diseases caused by defects in glycan biosynthesis, predominantly affecting the N-glycosylation pathway. Pathogenic variants in the DDOST gene, encoding a non-catalytic subunit of the oligosaccharyltransferase (OST) complex, underlie an ultra-rare CDG subtype with only three patients reported to date, complicating diagnosis and genotype-phenotype correlations. We describe a female patient with developmental delay, hypotonia, and dysmorphic features.  […] We also reviewed published DDOST-CDG cases to compare clinical and molecular findings.