Despite life-long galactose restriction, long-term complications generally occur in classical galactosemia. We report an adult male with classical galactosemia (Q188R homozygosity, severely reduced erythrocyte galactose-1-phosphate uridyltransferase activity) who has a surprisingly mild phenotype despite genotype and enzyme activity associated with severe phenotype. Moreover he has a normal galactose intake from the age of 3 years. This case is probably an example of the important role of yet unknown susceptibility and or modifier genes.
Panis, B., Bakker, J. A., Sels, J. P. J. E., Spaapen, L. J., van Loon, L. J., & Rubio-Gozalbo, M. E. (2006). Untreated classical galactosemia patient with mild phenotype. Molecular Genetics and Metabolism, 89(3), 277-279. https://doi.org/10.1016/j.ymgme.2006.03.002