Fetal phenotype of SLC35A2-CDG: Enlarged cisterna magna on ultrasound

Abstract

Congenital disorders of glycosylation (CDG) are rare conditions caused by genetic defects in glycan synthesis, processing or trans-port that are required in formation of glycoproteins and glycolipids. 1 Glycosylation involves an ever growing number of genes, encoding different proteins or enzymes. A defect of one of these genes can lead to a subtype of CDG, potentially affecting multiple organ sys-tems and always including an important neurological component. For example, CDG type IIm is known as SLC35A2-CDG due to a hemizygous or heterozygous variant in the X-linked gene SLC35A2 that encodes the major Golgi-localized UDP-galactose transporter required for proper protein and lipid glycosylation. 2 The manifesta-tions of SLC35A2-CDG include seizures, failure to thrive, developmental delay, and intellectual disability. Prenatal diagnosis is uncommon in SLC35A2-CDG cases. We here report such a fetal case with an enlarged cisterna magna identified by prenatal ultrasound. revealed An