Classification and goals - GAL

The term galactosemia refers to a group of disorders of galactose metabolism that includes classical galactosemia.

Classical galactosemia

Within days of ingesting breast milk or lactose-containing formulas, infants with classical galactosemia develop life-threatening complications¹.
Removal of all galactose of the diet during the first three to ten days of life, the signs resolve quickly and prognosis is good. Failure to implement effective newborn screening may have catastrophic consequences².
Even with early and adequate therapy, the long-term outcome in older children and adults with classical galactosemia can include cataracts, speech defects, poor growth, poor intellectual function, neurologic deficits (predominantly extrapyramidal findings with ataxia), and premature ovarian insufficiency (POI)³.

Management recommendations in classical galactosemia:

The aim of the management is to prevent the multi-organ toxicity syndrome that occurs after exposure to galactose derived from lactose in breast milk and/or infant formulas or dairy products. Next to lactose from milk, several fruits and vegetables contain a limited amount of galactose^4,1.

Significant endogenous galactose production will take place in galactosemia patients, which is age dependent, and relatively greater amounts are produced in infancy compared to adults. This endogenous galactose production may be an important contributor to long term outcomes⁵. The amount of intake of galactose from fruit and vegetables is relatively small compared to endogenous production. There was no difference in outcome found between clinics that did restrict fruits and vegetables as to those that did not restrict⁶.

Despite the long experience with classical galactosemia treatment, major controversies remain on the optimal strictness and duration of dietary galactose restriction⁶. At diagnosis infants are switched to a galactose free infant formula or even in some cases an elemental formula.

References

Dixon M, Macdonald A et al. Disorders of carbohydrate metabolism, In; Shaw V (ed) Clinical paediatric dietetics, 4^th John Wiley & Sons ltd. Sussex, 2015:526-539
Malone JI, Diaz-Thomas A. Problems with the new born screen for galactosaemia. BMJ Case Reports 2011; doi:10.1136/bcr.01.2011.3769
Schweitzer-Krantz S. Early diagnosis of inherited metabolic disorders towards improving outcome: the controversial issue of galactosemia. Eur J Pediatr 2003 Dec;162 Suppl 1:S50-3.
Huidekoper H, Bosch A, van der Crabben S, Sauerwein H, Ackermans M, Wijburg F. Short-term exogenous galactose supplementation does not influence rate of appearance of galactose in patients with classical galactosemia. Mol Genet Metab. 2005; 84:265–272.
Berry GT, Nissim I, Lin Z et al. Endogenous synthesis of galactose in normal men and patients with hereditary galactosemia. Lancet, 1995, 346 1073−4.
Bosch AM, Bakker HD et al. High tolerance for oral galactose in classical galactosemia: dietary implications. Arch Dis Child. 2004;89:1034-1036