A new case of UDP-galactose transporter deficiency (SLC35A2-CDG): molecular basis, clinical phenotype, and therapeutic approach

J Inherit Metab Dis. 2015 Sep;38(5):931-40. doi: 10.1007/s10545-015-9828-6. Epub 2015 Mar 17.


Congenital disorders of glycosylation (CDG) are a group of hereditary metabolic diseases characterized by abnormal glycosylation of proteins and lipids. Often, multisystem disorders with central nervous system involvement and a large variety of clinical symptoms occur. The main characteristics are developmental delay, seizures, and ataxia. In this paper we report the clinical and biochemical characteristics of a 5-year-old girl with a defective galactosylation of N-glycans, resulting in developmental delay, muscular hypotonia, epileptic seizures, inverted nipples, and visual impairment. Next generation sequencing revealed a de novo mutation (c.797G > T, p.G266V) in the X-chromosomal gene SLC35A2 (solute carrier family 35, UDP-galactose transporter, member A2; MIM 300896). While this mutation was found heterozygous, random X-inactivation of the normal allele will lead to loss of normal SLC35A2 activity in respective cells. The functional relevance of the mutation was demonstrated by complementation of UGT-deficient MDCK-RCA(r) and CHO-Lec8 cells by normal UGT-expression construct but not by the mutant version. The effect of dietary galactose supplementation on glycosylation was investigated, showing a nearly complete normalization of transferrin glycosylation.

Publication types

  • Case Reports

MeSH terms

  • Animals
  • CHO Cells
  • Child, Preschool
  • Congenital Disorders of Glycosylation / genetics*
  • Congenital Disorders of Glycosylation / therapy*
  • Cricetinae
  • Cricetulus
  • DNA Mutational Analysis
  • Dogs
  • Female
  • Galactose / therapeutic use
  • Humans
  • Madin Darby Canine Kidney Cells
  • Monosaccharide Transport Proteins / deficiency
  • Monosaccharide Transport Proteins / genetics*
  • Phenotype


  • Monosaccharide Transport Proteins
  • UDP-galactose translocator
  • Galactose