Specimen Requirements

Alternate Specimen Requirements

Minimum Specimen Requirements

Stability

Days Performed

Mon

Turnaround Time

9 - 16 days

Methodology

Reference Range

Special Info

Specimen CANNOT be frozen. Specimen must arrive at performing lab within 48 hours of collection. New York State approved.

Clinical Info

Useful for diagnosis of galactokinase deficiency. Galactokinase (GALK) deficiency is the second most common form of galactosemia, affecting approximately 1/250,000 live births, with a higher frequency in the Romani population. Individuals with GALK deficiency have a milder clinical presentation than that seen in patients with classic galactosemia, galactose-1-phosphate uridyltransferase (GALT) deficiency. The major clinical manifestation is bilateral juvenile cataracts. GALK deficiency is treated with a lactose-restricted diet. Early treatment may prevent or reverse the formation of cataracts. In GALK deficiency, erythrocyte galactose-1-phosphate levels are generally normal and plasma galactose levels are generally elevated. The diagnosis is established by demonstrating deficient GALK enzyme activity in erythrocytes. Testing for GALK deficiency should be performed when there is a suspicion of galactosemia, either based upon the patient's clinical presentation or laboratory studies and GALT deficiency has been excluded. Specimens sent for GALT analysis may be used for GALK testing if the original specimen was received in the laboratory within 48 hours of draw. GALK deficiency is caused by mutations in the GALK1 gene. Gene analysis is available from some commercial laboratories. Cautions: It is important to notify the laboratory if the patient has been transfused prior to specimen collection. The results of testing performed in erythrocytes are invalid following a transfusion, including analysis of enzymes, biochemical phenotyping, or galactose-1-phosphate.