A 9-month-old child is presented to the emergency room by his parents who report that he has been vomiting and has severe diarrhea. The episodes of vomiting began when the mother stopped breastfeeding and switched to the use of child cow's milk. The infant exhibits signs of failure to thrive, weight loss, hepatomegaly, and jaundice. Laboratory tests show elevated blood galactose, hypergalactosuria, and metabolic acidosis with coagulation deficiency characteristic of classic galactosemia. Which of the following is most likely to occur if this child continues to consume cow's milk?

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Quizplus · Accepted Answer

Type 1 galactosemia occurs as a consequence of mutations in the gene encoding GALT. Classic galactosemia manifests by a failure of neonates to thrive. Vomiting and diarrhea occur following ingestion of milk, hence individuals are termed lactose intolerant. Clinical findings include impaired liver function (which if left untreated leads to severe cirrhosis), elevated blood galactose, hypergalactosemia, hyperchloremic metabolic acidosis, urinary galactitol excretion, and hyperaminoaciduria. Unless controlled by exclusion of galactose from the diet, these patients can go on to develop blindness and fatal liver damage. Blindness is due to the conversion of circulating galactose to the sugar alcohol galacitol, by an NADPH-dependent aldose reductase that is present in neural tissue and in the lens of the eye.

A 9-Month-Old Child Is Presented to the Emergency Room by His