CONGENITAL NEPHROTIC SYNDROME - A NOVEL PHENOTYPE OF TYPE-I CARBOHYDRATE-DEFICIENT GLYCOPROTEIN SYNDROME

Type I carbohydrate-deficient glycoprotein (CDG) syndrome is a genetic multisystem disorder generally without overt renal problems. We repor t a neonate with neurological abnormalities and congenital nephrotic s yndrome of diffuse mesangial sclerosis type. Serum transferrin isoelec tric focusing showed the typical abnormalities of type I CDG syndrome. Normal transferrin focusing findings in other patients with similar r enal problems excluded the possibility of a secondary biochemical phen omenon. The diagnosis of type I CDG syndrome was confirmed by demonstr ation of a deficiency of phosphomannomutase. No evidence of pontocereb ellar atrophy was found in imaging or at autopsy. We conclude that con genital nephrotic syndrome may occur in type I CDG syndrome, and that this diagnosis should be considered in patients with congenital nephro tic syndrome. Absence of pontocerebellar atrophy does not exclude the diagnosis of type I CDG syndrome.