Galactokinase Deficiency
Galactokinase deficiency (GALK), a mild type of galactosemia, is an inherited disorder that impairs the body's ability to process and produce energy from a simple sugar called galactose. If babies with GALK eat foods containing galactose, undigested sugars build up in the blood. Galactose is present in many foods, including all dairy products, many baby formulas, and some fruits and vegetables. Children with GALK who are not treated with dietary therapy develop cataracts in the eyes, but otherwise they typically do not have long-term health problems. Rarely, a child with GALK will have pseudotumor cerebri, a condition which mimics the symptoms of a large brain tumor when no brain tumor is present. This is thought to be caused by increased pressure in the brain from cerebrospinal fluid (CSF) due to elevated levels of a galactose product in the CSF. The severe medical problems that occur with "classic" galactosemia (type 1), such as liver, kidney, and brain damage, typically are not present in people with GALK.
GALK is caused by mutations in the GALK1 gene and inheritance is autosomal recessive. The disorder may be suspected in babies with an abnormal newborn screening result, or in babies with cataracts. The diagnosis can be confirmed with biochemical and molecular genetic testing. The treatment is dietary therapy, which involves taking calcium supplements and restricting galactose in the diet throughout life to prevent cataracts. If cataracts develop, they usually resolve with dietary therapy. Children with GALK should have their growth monitored, and both children and adults should consult with a dietitian and have regular eye exams.
GALK is caused by mutations in the GALK1 gene and inheritance is autosomal recessive. The disorder may be suspected in babies with an abnormal newborn screening result, or in babies with cataracts. The diagnosis can be confirmed with biochemical and molecular genetic testing. The treatment is dietary therapy, which involves taking calcium supplements and restricting galactose in the diet throughout life to prevent cataracts. If cataracts develop, they usually resolve with dietary therapy. Children with GALK should have their growth monitored, and both children and adults should consult with a dietitian and have regular eye exams.