Galactokinase deficiency


Galactokinase deficiency, also known as Galactosemia type 2 or GALK deficiency, is marked by an accumulation of galactose and galactitol secondary to the decreased conversion of galactose to galactose-1-phosphate by galactokinase


* Absence of inanition * Gastrointestinal disorders * Jaundice * Progressive vision loss * Blindness


Galactokinase deficiency is an autosomal recessive genetic disorder mapped to band 17q24. At least 20 mutations are known to exist, of which the P28T mutation is considered the founder mutation.


Newborn screening is the act of testing all infants for a specific disease shortly after birth for the purpose of preventing disease progression through prompt medical treatment. When newborn screening for the inherited disease phenylketonuria (PKU) began in 1962, it quickly became clear that many infants with PKU were being identified for early treatment and that the mental retardation caused by the disease was being prevented.


Abundant experience with early treatment supports the concept that effective treatment instituted in the initial weeks of life can prevent all symptoms of the disease. In the rare event that some degree of mild retardation results, it is likely irreversible. Cataracts appear to be reversible if treatment is started within the initial three months of life.


The galactosemia syndromes are effectively treated by rigid dietary exclusion of all lactose and galactose, primarily involving the elimination of milk and its products. A galactose-free diet should be initiated as early as possible, particularly because cataract formation may be reversed in early stages. Non-lactose milk substitutes are often used. Although soybean preparations contain bound galactose, they appear to be well-tolerated because the bound galactose is not readily absorbed by the intestine.