Gastrointestinal Health in Classic Galactosemia
Classic galactosemia (CG) is an autosomal recessive disorder of galactose metabolism that affects approximately 1/50,000 live births in the USA. Following exposure to milk, which contains large quantities of galactose, affected infants may become seriously ill. Early identification by newborn screening with immediate dietary galactose restriction minimizes or prevents the potentially lethal acute symptoms of CG. However, more than half of individuals with CG still experience long-term complications including cognitive disability, behavioral problems, and speech impairment. Anecdotal reports have also suggested frequent gastrointestinal (GI) problems, but this outcome has not been systematically addressed. In this study we explored the prevalence of GI symptoms among 183 children and adults with CG (cases) and 190 controls. Cases reported 4.5 times more frequent constipation (95% CI 1.8–11.5) and 4.2 times more frequent nausea (95% CI 1.2–15.5) than controls. Cases with genotypes predicting residual GALT activity reported less frequent constipation than cases without predicted GALT activity but this difference was not statistically significant. Because the rigor of dietary galactose restriction varies among individuals with galactosemia, we further tested whether GI symptoms associated with diet in infancy. Though constipation was almost four times as common among cases reporting a more restrictive diet in infancy, this difference was not statistically significant. These data confirm that certain GI symptoms are more common in classic galactosemia compared to controls and suggest that future studies should investigate associations with residual GALT activity and dietary galactose restriction in early life.
First, we thank the Galactosemia Foundation and the many individuals and families who participated in this study; without them none of this work would have been possible. We are also grateful to Drs. Tanvi Dhere and Sandy van Calcar for invaluable guidance in the early stages of this project, and to Dr. K. Alaine Broadaway for early assistance with R. This study was funded in part by NIH grant R01 DK059904 (to JLFK). KAS was supported at different times by funds from training grant ID#1008188 (BWF), training grant T32GM008490 (NIH), and NRSA F31DK107229 (NIH).
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