A 3-Year-Old With Gingival Hemorrhage and Musculoskeletal Pain.

A 3-year-old had spontaneous gingival hemorrhage and bilateral limb weakness with inability to bear weight. He had no preceding oral trauma or recent infection, took no regular medications, and had no recent use of aspirin or nonsteroidal anti-inflammatory drugs; his diet was limited to primarily chicken nuggets and milk. What is the diagnosis and what would you do next?