DPM2 deficiency is an ultra-rare inherited metabolic disorder caused by mutations (pathogenic variants) in DPM2, which is a gene coding for DPM2 protein. Individuals with DPM2 deficiency have two faulty copies of DPM2 gene, each inherited from one of the parents. DPM2 protein is involved in a process called glycosylation. Therefore, the disorder is classified as DPM2-congenital disorder of glycosylation (DPM2-CDG). There have been only 4 individuals with DPM2-CDG reported up to date.