The parents of a 4-month-old infant bring their child to his pediatrician because they are concerned about his difficulty in feeding, irritability, and his overall floppiness. The pediatrician notes that the infant has pudgy, rosy, cheeks and brittle, easily broken hair. The doctor suspects the child is suffering from Menkes disease. Given that the physician is correct in her diagnosis, the lack of which of the following would likely be found in this patient?

Question

Quizplus · Accepted Answer

Menkes disease is inherited as an X-linked disorder of copper homeostasis. The disorder is associated with an inability to absorb copper from the gastrointestinal tract. As a consequence of the reduced delivery of copper to the brain, Menkes patients exhibit severe mental and developmental impairment. In addition, because there is a need for copper as a cofactor in numerous enzymes (eg, lysyl oxidases) Menkes patients also exhibit connective tissue abnormalities. Menkes disease is the result of defects in the P-type ATPase protein that is responsible for the translocation of copper across the intestinal basal-lateral membrane into the blood, thus allowing for uptake of dietary copper. This protein is encoded by the ATPase, Cu²⁺-transporting, α-polypeptide (ATP7A) gene.

The Parents of a 4-Month-Old Infant Bring Their Child to His