An 8-year-old boy is brought to his pediatrician for developing multiple bruises over the course of the school year. The patient's mother believes the child is being bullied at school. The patient is otherwise healthy. Family history is significant for his father expiring at 38 yearas of age due to a severe subarachnoid hemorrhage. On physical exam, there are ecchymoses and hematomas over the shins and knees. The skin also appears fragile and thin, which demonstrates a venous pattern in the extremities. A skin biopsy is performed, and histochemical evaluation of the biopsy reveals a defect in extracellular processing of collagen. Which of the following steps of collagen synthesis is most likely impaired in this patient?

Question

An 8-year-old boy is brought to his pediatrician for developing multiple bruises over the course of the school year. The patient's mother believes the child is being bullied at school. The patient is otherwise healthy. Family history is significant for his father expiring at 38 yearas of age due to a severe subarachnoid hemorrhage. On physical exam, there are ecchymoses and hematomas over the shins and knees. The skin also appears fragile and thin, which demonstrates a venous pattern in the extremities. A skin biopsy is performed, and histochemical evaluation of the biopsy reveals a defect in extracellular processing of collagen.  Which of the following steps of collagen synthesis is most likely impaired in this patient?

Quizplus · Accepted Answer

Eductional Objective: Ehlers-Danlos syndrome is a group of rare hereditary disorders characterized by defective collagen synthesis.  It can be caused by procollagen peptidase deficiency, which results in impaired cleavage of terminal propeptides in the extracellular space.  Patients often have joint laxity, hyperextensible skin, and tissue fragility due to the formation of soluble collagen that does not properly crosslink.

An 8-Year-Old Boy Is Brought to His Pediatrician for Developing