Galactosemia is a rare genetic disorder in which galactose cannot be converted to glucose and instead accumulates in the blood. If infants born with this condition are left untreated, they die in 75% of cases.

Babies are screened for galactosemia at birth as part of routine newborn screening and this is usually how the disease is detected.

The condition is caused by a mutation in the gene that codes for the enzyme galactose-1-phosphate uridyl transferase or GALT. This enzyme is involved in a series of steps that converts galactose to glucose, which is then used for energy.

If the enzyme is missing, then galactose builds up in the infant’s blood which can lead to a range of complications from slurred speech to cardiac problems and death.

Screening

Newborns are screened for this condition using a blood sample taken as a heel prick test. The drop of blood from the patient’s heel is dried and checked for the GALT enzyme.

The level of galactose and galactose 1-phosphate in the blood can also be checked. Genetic testing to look for mutations in the GALT gene may be useful in confirming a diagnosis.

Clinical features

Examples of clinical features that may cause galactosemia to be suspected include:

• Lethargy
• Refusal to feed
• Failure to thrive and gain weight
• Delayed development
• Vomiting
• Diarrhea
• Jaundice
• Death a few days after birth
• Bleeding tendencies
• Coagulation defects
• Cataracts
• Fluid in the abdomen or ascitis
• Liver and/or kidney damage