The original description of the<unk>  is characterized by a generally good prognosis and an excellent response to treatment with corticosteroids; however, in actuality it is clear that there is a group of patients with elevated morbidity and mortality. In a recent study the survival rates at 5, 10, and 15 years were 98%, 96%, and 88% respectively, with the main causes of death being pulmonary hypertension, cardiovascular problems, and infections. The presence of anticardiolipin antibodies is a more serious risk factor for the<unk> , as well as the presence of more scleroderma and polymyositis signs and symptoms. Morbidity is quite high in patients with<unk> . In addition to fatigue and recurrent musculoskeletal complaints, patients can develop a fibromyalgia symptom as a result of occasional outbreaks requiring medium-high doses of corticosteroid. The steroids, in combination with their adverse effects, frequently cause fibromyalgia symptoms and thus complicate treatment. The prognosis of<unk>  is in one third of cases worse than that of systemic lupus erythematosus (SLE). In spite of prednisone treatment, this<unk>  is progressive and may in many cases evolve into a progressive systemic sclerosis (PSS), also referred to as diffuse cutaneous systemic scleroderma (dcSSc) which has a poor outcome. In some cases though the<unk>  is mild and may only need aspirin as a treatment and may go into remission where no Anti-U1-RNP antibodies are detected, but that is rare or within 30% of cases. Most deaths from<unk>  are due to heart failure caused by pulmonary arterial hypertension (PAH).<unk>  progression Patients diagnosed with<unk>  may progress to a clinical picture more consistent with other<unk>  tissue<unk> s like SLE, scleroderma, or rheumatoid arthritis. In some studies these patients become reclassified over time with other<unk> s, such as rheumatoid arthritis in 9%, SLE in 15%, and scleroderma in 21% of cases. Such progression is, in part, determined genetically, thus SLE is more likely in patients with HLA-DR3 and scleroderma in patients with HLA-DR5.
Mixed connective tissue disease
Carnitine palmitoyltransferase II
Undifferentiated connective tissue disease
Scleroderma
Systemic scleroderma
Antisynthetase syndrome
CREST syndrome
Cryopyrin-associated periodic syndrome