Additional symptoms such as hepatomegaly (galactose-1-phosphate uridylyltransferase deficiency, COG5-CDG and PMM2-CDG), hypertrophic cardiomyopathy (dihydrolipoamide dehydrogenase deficiency), pulmonary embolism (Lesch-Nyhan syndrome), urinary tract infections (Lesch-Nyhan syndrome), and optic atrophy (OPA3 deficiency, neuronal ceroid lipofuscinosis, phosphatidylserine flippase deficiency and 3-methylglutaconic aciduria) were also present in the cohort (Figure 1G). Here, PMM2 is linked to neuronal ceroid lipofuscinosis.