COG1-congenital disorders of glycosylation: Milder presentation and review.

Congenital disorders of glycosylation (CDG) are a heterogeneous group of genetic defects in glycoprotein and glycolipid glycan synthesis and attachment. A CDG subgroup are defects in the conserved oligomeric Golgi complex encoded by eight genes, COG1-COG8. Pathogenic variants in all genes except the COG3 gene have been reported. COG1-CDG has been reported in five patients. We report a male with neonatal seizures, dysmorphism, hepatitis and a type 2 serum transferrin isoelectrofocusing. Exome sequencing identified a homozygous COG1 variant (NM_018714.3: c.2665dup: p.[Arg889Profs*12]), which has been reported previously in one patient. We review the reported patients.