Mosaicism of the UDP-Galactose Transporter SLC35A2 Causes a Congenital Disorder of Glycosylation

摘要: Biochemical analysis and whole-exome sequencing identified mutations in the Golgi-localized UDP-galactose transporter SLC35A2 that define an undiagnosed X-linked congenital disorder of glycosylation (CDG) three unrelated families. Each mutation reduced UDP-galactose transport, leading to galactose-deficient glycoproteins. Two affected males were somatic mosaics, suggesting that a wild-type allele may be required for survival. In infancy, commonly used biomarker transferrin showed abnormal glycosylation, but its appearance became normal later childhood, without any corresponding clinical improvement. This indicate selection against cells carrying mutant allele. To detect other individuals with such mutations, we suggest testing infancy. Here, report mosaicism CDG, our work stresses importance combining both genetic biochemical diagnoses.