As the ER physician you are tending to a 59-year-old female patient who has a broken left fibula. Upon physical exam you discover she also has multiple bruises on her arms, legs, and upper torso. She also complains of painful gums and significant bleeding whenever she brushes her teeth. She reports that she subsists on bouillon soup, tea, plain pasta, and dinner rolls. Blood work indicates that she is mildly anemic with microcytic erythrocytes. Given these signs and symptoms, this patient most likely is suffering from the effects of a deficiency in the activity of which of the following enzymes?

Question

Quizplus · Accepted Answer

The patient's symptoms and dietary habits suggest scurvy, which is caused by vitamin C deficiency. Vitamin C is a cofactor for lysyl hydroxylase, an enzyme involved in collagen synthesis. Deficiency leads to poor collagen formation, resulting in bruising, bleeding gums, and bone issues.  The signs and symptoms exhibited by this patient are indicative of scurvy which results from a deficiency of vitamin C (ascorbate). Vitamin C is a critical co-factor for the enzymes lysyl hydroxylase and prolyl hydroxylase that are required for the correct posttranslational modification of collagen. Loss of collagen processing leads to defective connective tissue synthesis and also results in poor platelet adhesion to exposed sub-endothelial extracellular matrix resulting prolonged bleeding time. Often times vitamin C deficient patients also exhibit mild anemia due to the role of vitamin C in the process of intestinal absorption of Fe2+ iron.

As the ER Physician You Are Tending to a 59-Year-Old