Evaluation of Efficacy and Safety of D-galactose Supplementation in SLC35A2-CDG, a Disorder of Hypogalactosylation

Inclusion Criteria * Molecular confirmation of SLC35A2 genetic variant * Age \> 1 month * Presence of seizures, chronic vomiting, chronic constipation, or chronic diarrhea * A parent or legal guardian must be available and willing to provide consent on behalf of minor subjects or adult subjects who are unable to give informed consent due to developmental disabilities. * Use of contraception in females \> age 8 years * Previously performed eye exam within last year Exclusion Criteria * Aldolase-B deficiency * Galactosemia * Hemolytic uremic syndrome * Hemoglobin \< 7 mg/dL * LFTs \> 3x ULN *…