Rat model study probes prenatal origins of long-term complications in classic galactosemia
A PLOS Genetics study using GALT-deficient rats documents elevated galactose metabolites and downstream consequences in utero, suggesting that complications may begin before birth.
Researchers at Emory University School of Medicine, led by Judith L. Fridovich-Keil and colleagues, have published a study in PLOS Genetics examining prenatal consequences of galactose-1-P uridylyltransferase (GALT) deficiency — the enzyme whose loss causes classic galactosemia (CG), a potentially life-threatening inherited metabolic disorder detectable by newborn screening.
Classic galactosemia is caused by biallelic loss-of-function variants in the GALT gene. Despite newborn screening and dietary restriction of galactose from birth, many affected individuals develop long-term complications including cognitive difficulties, speech and language problems, and, in females, primary ovarian insufficiency. The reasons why these complications persist despite early dietary intervention have remained poorly understood.
Prior work has shown that galactose metabolites accumulate in utero in CG. The new study, using a rat model of GALT deficiency, characterises the nature and extent of prenatal consequences in greater detail, with the authors investigating whether intrauterine exposure to elevated galactose metabolites may contribute to the long-term outcomes seen postnatally. The available data suggest prenatal effects are measurable, though the precise mechanisms linking foetal metabolite exposure to adult complications require further investigation.
For genetic counsellors and clinicians working with families affected by galactosemia, the findings add biological plausibility to the hypothesis that the window for intervention may extend to the prenatal period, a question with implications for how the disorder is conceptualised and monitored — though this remains a research finding rather than a basis for changed clinical practice.
Plain-language version
For patients, families, and general readers. Educational only — not medical advice.
Classic galactosemia is a rare inherited condition caused by the body's inability to properly process a sugar called galactose, found in dairy products and some other foods. It is detected at birth through newborn screening in many countries, and affected babies are immediately placed on a restricted diet.
Despite early dietary treatment, some people with galactosemia experience lasting problems such as learning difficulties or fertility issues. Scientists have wondered whether some of these complications might begin before birth, when a developing baby is exposed to high levels of galactose-related substances through the mother's metabolism.
Researchers publishing in the journal PLOS Genetics used rats that lack the GALT enzyme — the same enzyme affected in classic galactosemia — to study what happens before birth. Their findings suggest that galactose metabolites do accumulate in the womb and that this has measurable effects on development.
This is early-stage research in an animal model, and it does not change current guidance for managing galactosemia. Researchers say it may help explain why some long-term complications arise even with early treatment, which could eventually guide new research directions.
This is an educational summary, not medical advice. If anything here raises questions for you, please speak with your GP or a clinical professional.
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Primary source Public Library of Science · 2026-09-21Prenatal consequences of GALT deficiency in a rat model of classic galactosemia