ALG6 encodes an alpha-1,3-glucosyltransferase that catalyzes a critical step in N-linked protein glycosylation. This enzyme adds the first glucose residue to the lipid-linked oligosaccharide Man9GlcNAc2-PP-Dol in the endoplasmic reticulum lumen, producing Glc1Man9GlcNAc2-PP-Dol, which serves as the glycan precursor transferred to nascent proteins during their synthesis. Pathogenic ALG6 variants cause congenital disorder of glycosylation type Ic (ALG6-CDG), characterized by a recognizable neurological phenotype 1. Affected individuals present with hypotonia, developmental delay, and epilepsy in all cases, along with ataxia, proximal muscle weakness, and failure to thrive in most patients 1. Behavioral changes with autistic and depressive features occur frequently 1. Coagulation anomalies are present in fewer than 50% of cases, and some patients develop intractable seizures or fatal complications including protein-losing enteropathy 1. ALG6-CDG represents the second most common N-glycosylation disorder 1. Cardiac manifestations have been reported among congenital disorders of glycosylation 2. At the population level, gnomAD v4.1 classifies ALG6 as LoF-tolerant (LOEUF=0.89); however, this is distinct from clinical pathogenicity observed in disease contexts, where 149 ClinVar variants are classified as pathogenic or likely pathogenic. Current management focuses on symptom control, including seizure management with agents such as escitalopram and risperidone for psychiatric symptoms 3.