Patient's question:
What are the clinical manifestations of galactosemia in children? What tests are needed to confirm the diagnosis?Doctor's answer:
Hello: Galactosemia is a genetic disorder characterized by abnormal galactose metabolism, caused by a defect in 1-phosphogalactose uridylyltransferase, leading to the deposition of 1-phosphogalactose and galactitol, which results in disease. Based on changes in red blood cell and liver enzyme levels, this enzyme has several variants. The liver, kidneys, eye lenses, and brain tissue are the main organs affected.In the weeks following birth, the liver disease includes cholestasis, widespread fat degeneration, and no inflammatory cell infiltration. Later, pseudovascular formation, pseudoglandular hyperplasia, and hepatocyte destruction occur. Pseudoglandular hyperplasia is a characteristic feature of galactosemia but is not specific. As the disease progresses, fine fibrous tissue hyperplasia appears. Fibrous tissue hyperplasia begins in the periportal area and later extends to the portal area, forming bridging connections, followed by the formation of regenerative nodules. During the progression of cirrhosis, the changes are similar to those seen in alcoholic cirrhosis, with no significant inflammatory cell infiltration throughout the disease process.
In addition to liver disease, renal cortex and medullary junctional tubular dilation may occur. Portal hypertension can lead to splenomegaly, and brain involvement is mild. The severity of the disease varies greatly. Some children may develop acute, fulminant disease after the first breastfeeding, while most progress subacutely. Gastrointestinal symptoms include jaundice, anorexia, abdominal distension, diarrhea, vomiting, and hypoglycemia. Ascites may appear within 2–5 weeks, and cataracts can develop within days of birth. If the mother consumes excessive dairy products during pregnancy, the infant may develop jaundice shortly after birth. Infants with the above clinical manifestations should be suspected of having this disease.
Elevated galactose levels in blood and urine, particularly when urine glucose tests are positive but glucose oxidase-based urine glucose tests are negative, can diagnose the disease. If possible, the level of 1-phosphogalactose uridylyltransferase in the child's red blood cells can be measured, as this enzyme is completely or nearly completely deficient. Early diagnosis should be followed by a galactose-free diet. Some advocate lifting dietary restrictions after the age of 8, but it is generally recommended to maintain this diet lifelong. With timely treatment, cataracts, hepatomegaly, and cirrhosis can be reversed.
It is important to note that asymptomatic homozygous females may experience elevated blood galactose levels after consuming high-lactose foods. The infants of these women may develop galactosemia, especially for mothers who have previously had infants with galactosemia. During pregnancy, these mothers should limit their galactose intake.