A 5-month-old infant is brought to her pediatrician because her parents are concerned about her general failure to thrive and a progressive yellowing of her eyes and skin. Upon examination it is noted the infant has slightly bowing legs indicative of rickets, hepatomegaly, poorly clotting blood, and fatty diarrhea. The ricketslike symptoms and the fatty stool are indicative of lipid maladsorption. The pediatrician makes a diagnosis of a bile acid metabolism disorder. Which of the following enzymes is likely to be defective in this infant?

Question

Quizplus · Accepted Answer

The symptoms suggest a defect in bile acid synthesis, leading to lipid malabsorption. 3b-hydroxy Δ⁵ C₂₇-steroid oxidoreductase (HSD3B7) is an enzyme involved in the early steps of bile acid synthesis. A defect in this enzyme can lead to the accumulation of toxic intermediates and impaired bile acid production, causing the symptoms observed.

A 5-Month-Old Infant Is Brought to Her Pediatrician Because Her