Benign hypermobility joint syndrome, or BHJS, affects more females than males and tends to affect children more than adults, according to WebMD. BHJS is a condition in which patients have more mobility in their joints than normal, causing pain and, sometimes, swelling.
BHJS rates vary by age, sex and ethnicity. As children get older, they may have fewer symptoms because they learn how to manage their pain and because the joints become stronger, notes WebMD. BHJS most commonly affects joints in the knees, elbows, wrists and fingers, explains MedlinePlus. Children with BHJS can develop problems, such as arthritis and sprains, due to the weakness of the ligaments holding their joints together.