As far as PGM1-CDG is concerned, liver involvement is observed in the multisystem phenotype (including congenital malformations, cardiomyopathy, variable endocrine and hematological abnormalities and no neurological disease); it has not been described in the muscular form of PGM1-CDG (7, 9, 14–16). Here, PGM1 is linked to nervous system disorder.