Classical Galactosemia (GALT) Sequencing

Disorder Galactosemia
Gene Name GALT
Clinical info Galactosemia is an autosomal recessive inborn error of carbohydrate metabolism caused by the deficiency of galactose-1-phosphate uridyl transferase (GALT), which performs the second enzymatic step in the conversion of galactose to glucose-1-phosphate.  As a result of the enzyme deficiency, excess galactose is excreted in the urine and the substrate for GALT, galactose-1-phosphate, accumulates throughout the body. Manifestations of the disease appear within days of the initiation of milk feedings, and include vomiting, jaundice and failure to thrive. If left untreated for a prolonged period of time, patients will develop hepatomegaly, cataracts and intellectual disability. Speech delay and premature ovarian failure are also observed in many galactosemia patients, even in those who are diagnosed early and put on treatment. Galactosemia is typically detected very early because of newborn screening programs, which measure GALT enzyme activity in dried blood spots. Mutations in the GALT gene are responsible for the classic form of galactosemia (G/G). This sequencing analysis can help identify the disease causing mutations in patients.
Indications Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutations within a family to allow for carrier testing and prenatal diagnosis.
Detection A mutation in GALT will be indentified in approximately 99% of patients with classic galacossemia.
Associated Tests Galactose-1-phosphate biochemical analysis
Specimen Requirements 5 to 10 ml of peripheral blood collected in an EDTA (lavender top) Vacutainer tube is preferred.  The minimal blood needed for reliable DNA isolation is 3 ml
Transport The specimen should be kept at room temperature and delivered via overnight shipping. FedEx is preferred. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.
Turnaround time 10 days
Prenatal testing Prenatal diagnosis is available if the familial mutations are known. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests Contact the laboratory prior to sending a prenatal specimen.
CPT Codes Unknown mutation: 81406

Known mutation: 81403

Deletion/Duplication Analysis: 81229
Cost $800 for sequencing

$350 for known mutation

$700 for deletion/duplication analysis

Prenatal diagnosis for known mutation is $1000.  Please contact the laboratory for more information.

Contact For further information contact This email address is being protected from spambots. You need JavaScript enabled to view it. , MS, Lab Counselor at 1-800-473-9411.

Molecular Diagnostic Lab

The Molecular Diagnostic Lab offers DNA analysis for many genetic disorders via gene sequencing, targeted mutation analysis, MLPA deletion/duplication testing, trinucleotide repeat analysis and next generation sequencing panels.

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