ALG1-CDG

ALG1-CDG is an autosomal recessive congenital disorder of glycosylation caused by biallelic pathogenic variants in the ALG1 gene. It was originally named CDG-IK under the earlier nomenclature for these disorders. The first cases were described in 2004, the same year the causative gene was identified. Clinically, affected people have developmental delay, hypotonia, seizures and microcephaly. Fewer than 60 cases have been confirmed in the published literature. The disorder can be suspected from clinical findings and an abnormal serum transferrin glycosylation test, and confirmed by sequence analysis of ALG1, a step complicated by the presence of a pseudogene. No specific treatment exists, and care consists mostly of managing symptoms.