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SLC35A2 gene

solute carrier family 35 member A2

Normal Function

The SLC35A2 gene provides instructions for making an enzyme called UDP-galactose translocator (UGT). This enzyme is involved in a process called glycosylation. During this process, complex chains of sugar molecules (oligosaccharides) are added to proteins and fats (lipids). Glycosylation modifies proteins and lipids so they can fully perform their functions. The UGT enzyme transfers a simple sugar called galactose to growing oligosaccharides at a particular step in the formation of the sugar chain. Once the correct number of sugar molecules are linked together, the oligosaccharide is attached to a protein or lipid.

Two versions of the enzyme, known as UGT1 and UGT2, are produced from the SLC35A2 gene. These enzymes differ in only a few protein building blocks (amino acids) and can function together or separately in different areas of the cell.

Health Conditions Related to Genetic Changes

SLC35A2-congenital disorder of glycosylation

At least nine mutations in the SLC35A2 gene have been found to cause SLC35A2-congenital disorder of glycosylation (SLC35A2-CDG). SLC35A2-CDG is an inherited condition that causes neurological problems (such as seizures, developmental delay, and intellectual disability) and abnormalities affecting other body systems.

SLC35A2 gene mutations change single amino acids in the UGT enzyme or disrupt the way the gene's instructions are used to make the enzyme. These mutations can affect one or both versions of the enzyme and lead to the production of an abnormal enzyme with reduced or no activity. Without a properly functioning enzyme, glycosylation cannot proceed normally, and oligosaccharides are incomplete. The signs and symptoms of SLC35A2-CDG are likely due to impaired glycosylation of proteins and fats that are needed for the normal function of various organs and tissues.

In some individuals with SLC35A2-CDG, glycosylation becomes normal later in childhood. The cause of this apparent correction is unknown. The restoration of glycosylation in these individuals, however, does not seem to improve the signs and symptoms of SLC35A2-CDG.

More About This Health Condition

Other Names for This Gene

  • solute carrier family 35 (UDP-galactose transporter), member 2
  • solute carrier family 35 (UDP-galactose transporter), member A2
  • UDP-Gal-Tr
  • UDP-galactose translocator
  • UGAT
  • UGT
  • UGT1
  • UGT2
  • UGTL

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Gene and Variant Databases


  • Dorre K, Olczak M, Wada Y, Sosicka P, Gruneberg M, Reunert J, Kurlemann G, Fiedler B, Biskup S, Hortnagel K, Rust S, Marquardt T. 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. Citation on PubMed
  • Kimizu T, Takahashi Y, Oboshi T, Horino A, Koike T, Yoshitomi S, Mori T, Yamaguchi T, Ikeda H, Okamoto N, Nakashima M, Saitsu H, Kato M, Matsumoto N, Imai K. A case of early onset epileptic encephalopathy with de novo mutation in SLC35A2: Clinical features and treatment for epilepsy. Brain Dev. 2017 Mar;39(3):256-260. doi: 10.1016/j.braindev.2016.09.009. Epub 2016 Oct 12. Citation on PubMed
  • Kodera H, Nakamura K, Osaka H, Maegaki Y, Haginoya K, Mizumoto S, Kato M, Okamoto N, Iai M, Kondo Y, Nishiyama K, Tsurusaki Y, Nakashima M, Miyake N, Hayasaka K, Sugahara K, Yuasa I, Wada Y, Matsumoto N, Saitsu H. De novo mutations in SLC35A2 encoding a UDP-galactose transporter cause early-onset epileptic encephalopathy. Hum Mutat. 2013 Dec;34(12):1708-14. doi: 10.1002/humu.22446. Epub 2013 Oct 15. Citation on PubMed
  • Ng BG, Buckingham KJ, Raymond K, Kircher M, Turner EH, He M, Smith JD, Eroshkin A, Szybowska M, Losfeld ME, Chong JX, Kozenko M, Li C, Patterson MC, Gilbert RD, Nickerson DA, Shendure J, Bamshad MJ; University of Washington Center for Mendelian Genomics; Freeze HH. Mosaicism of the UDP-galactose transporter SLC35A2 causes a congenital disorder of glycosylation. Am J Hum Genet. 2013 Apr 4;92(4):632-6. doi: 10.1016/j.ajhg.2013.03.012. Citation on PubMed or Free article on PubMed Central

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.