Galactokinase deficiency: lessons from the GalNet registry

M. Estela Rubio-Gozalbo*, Britt Derks, Anibh Martin Das, Uta Meyer, Dorothea Moeslinger, M. Luz Couce, Aurelie Empain, Can Ficicioglu, Natalia Julia Palacios, Mariela M. De Los Santos De Pelegrin, Isabel A. Rivera, Sabine Scholl-Buergi, Annet M. Bosch, David Cassiman, Didem Demirbas, Matthias Gautschi, Ina Knerr, Philippe Labrune, Anastasia Skouma, Patrick VerlooSaskia B. Wortmann, Eileen P. Treacy, David J. Timson, Gerard T. Berry

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Purpose Galactokinase (GALK1) deficiency is a rare hereditary galactose metabolism disorder. Beyond cataract, the phenotypic spectrum is questionable. Data from affected patients included in the Galactosemias Network registry were collected to better characterize the phenotype. Methods Observational study collecting medical data of 53 not previously reported GALK1 deficient patients from 17 centers in 11 countries from December 2014 to April 2020. Results Neonatal or childhood cataract was reported in 15 and 4 patients respectively. The occurrence of neonatal hypoglycemia and infection were comparable with the general population, whereas bleeding diathesis (8.1% versus 2.17-5.9%) and encephalopathy (3.9% versus 0.3%) were reported more often. Elevated transaminases were seen in 25.5%. Cognitive delay was reported in 5 patients. Urinary galactitol was elevated in all patients at diagnosis; five showed unexpected Gal-1-P increase. Most patients showed enzyme activities A (p.Pro28Thr). Thirty-five patients were diagnosed following newborn screening, which was clearly beneficial. Conclusion The phenotype of GALK1 deficiency may include neonatal elevation of transaminases, bleeding diathesis, and encephalopathy in addition to cataract. Potential complications beyond the neonatal period are not systematically surveyed and a better delineation is needed.

Original languageEnglish
Pages (from-to)202-210
Number of pages9
JournalGenetics in Medicine
Issue number1
Early online date18 Aug 2020
Publication statusPublished - Jan 2021


  • galactokinase 1 deficiency
  • cataract
  • galactosemias registry
  • GALK1gene variants
  • neonatal complications


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