Joint hypermobility syndrome (JHS) is a condition in which the joints of the body are more flexible than normal due to excessive ligamentous laxity. This can cause joint pain, fatigue, and dysfunction, and can increase the risk of injury and long-term health problems.

Vasculitides are a heterogeneous group of inflammatory diseases that affect blood vessels, including arteries, veins, and capillaries. The inflammation can cause damage to the blood vessel wall and compromise blood flow to affected organs. The diagnosis and treatment of vasculitis can be complex, since there are multiple subtypes with different clinical presentations and laboratory patterns.

Systemic exercise intolerance disease (SEID) is a chronic and complex disease characterized by intolerance to physical and/or mental exertion. SEID is a syndrome that manifests with symptoms such as fatigue, muscle and joint pain, cognitive dysfunction, and sleep disturbances.

Sarcoidosis is a multisystem disease of unknown origin characterized by the formation of non-caseating granulomas in different organs and tissues, especially in the lungs, lymph nodes, eyes, skin and joints. The etiology of sarcoidosis is uncertain, although it is thought to be an abnormal immune response to an unknown antigen in genetically susceptible individuals.