A Thijs, Patrícia Janeiro, Ina Knerr, Ana I. Coelho, Aurélie Hubert, Dirk Müller-Wieland, Philippe Labrune, D Ramadza, M T Forga, Isabel Rivera, Rein Vos, Saskia B. Wortmann, María L. Couce, Gerard T. Berry, Christel Tran, Elaine Murphy, Didem Demirbas, Roshni Vara, Charlotte Dawson, Janneke G. Langendonk, Katrin Õunap, Mendy M. Welsink-Karssies, M Haskovic, Eileen P. Treacy, Johannes Häberle, Matthias Gautschi, Annet M. Bosch, Stephanie Grunewald, Gepke Visser, Birute Burnyte, S Scholl-Buergi, David Cassiman, M. E. Rubio-Gozalbo, Susan E. Waisbren, Yuval Landau, François Eyskens, Karolina M. Stepien, Jorg Kotzka, H H Huidekoper, Michel Hochuli, Dorothea Möslinger, Terry G J Derks, M.S. de Vries, Center for Liver, Digestive and Metabolic Diseases (CLDM), Universidade de Santiago de Compostela. Departamento de Ciencias Forenses, Anatomía Patolóxica, Xinecoloxía e Obstetricia, e Pediatría, Paediatric Metabolic Diseases, AGEM - Inborn errors of metabolism, Pediatrics, Internal Medicine, Medical Informatics, Kindergeneeskunde, MUMC+: MA Medische Staf Kindergeneeskunde (9), RS: GROW - R4 - Reproductive and Perinatal Medicine, Promovendi ODB, FHML Methodologie & Statistiek, RS: CAPHRI other, Internal medicine, ACS - Diabetes & metabolism, AGEM - Endocrinology, metabolism and nutrition, and Amsterdam Reproduction & Development (AR&D)
Background: Classic galactosemia is a rare inborn error of carbohydrate metabolism, caused by a severe deficiency of the enzyme galactose-1-phosphate uridylyltransferase (GALT). A galactose-restricted diet has proven to be very effective to treat the neonatal life-threatening manifestations and has been the cornerstone of treatment for this severe disease. However, burdensome complications occur despite a lifelong diet. For rare diseases, a patient disease specific registry is fundamental to monitor the lifespan pathology and to evaluate the safety and efficacy of potential therapies. In 2014, the international Galactosemias Network (GalNet) developed a web-based patient registry for this disease, the GalNet Registry. The aim was to delineate the natural history of classic galactosemia based on a large dataset of patients. Methods: Observational data derived from 15 countries and 32 centers including 509 patients were acquired between December 2014 and July 2018. Results: Most affected patients experienced neonatal manifestations (79.8%) and despite following a diet developed brain impairments (85.0%), primary ovarian insufficiency (79.7%) and a diminished bone mineral density (26.5%). Newborn screening, age at onset of dietary treatment, strictness of the galactose-restricted diet, p.Gln188Arg mutation and GALT enzyme activity influenced the clinical picture. Detection by newborn screening and commencement of diet in the first week of life were associated with a more favorable outcome. A homozygous p.Gln188Arg mutation, GALT enzyme activity of ≤ 1% and strict galactose restriction were associated with a less favorable outcome. Conclusion: This study describes the natural history of classic galactosemia based on the hitherto largest data set. The initial GalNet meeting to discuss the registry was financially supported by a grant to M.E.R-G. from The Netherlands Organisation for Scientific Research (NWO). Development, implementation and maintenance were supported by grants from the Dutch Galactosemia Research foundation, European Galactosemia Society and Metakids grants to M.E. R-G. Data entry for 6 of the 7 participating Dutch centers was done by the coordinating center and was financially supported by a Stofwisselkracht grant to M.E.R-G. in 2016. Analysis and interpretation of data was financially supported by Stofwisselkracht and Metakids grants to M.E.R-G. (2017 and 2018). The Irish data entry was supported by a national Health Research Board (HRB) grant to E.P.T. The British inherited Metabolic Disease Group supported access to the registry in the UK. M.G. was supported by a grant from the Batzebär foundation of the University Hospital Bern, and one from the Galaktosämie Schweiz patient organization for the set-up of the registry and data entry for all patients of Switzerland. The Spanish Galactosemia foundation financially supported data entry for Spanish patients. SI