Mitral valve prolapse in autoimmune thyroid disease: An index of systemic autoimmunity?

A coexistence of mitral valve prolapse (MVP) with autoimmune thyroid diseas e (AITD) has been described, but there are not sufficient data to explain t his association. The aim of the present study was to investigate the preval ence of MVP in patients with AITD and to evaluate whether any correlation b etween MVP and certain immunological parameters exists. M-mode, two-dimensi onal Doppler echocardiography was performed in 29 patients with Graves' dis ease (GD), 35 with Hashimoto's thyroiditis (HT), 20 with nonautoimmune goit er, and 30 normal controls. Serum samples were examined for antinuclear ant ibodies (ANA), antibodies against extractable nuclear antigen (ENA), antiph ospholipid antibodies (aCL), rheumatoid factor (RF), thyroid autoantibodies (TAAb), immunoglobulins and C3, C4. Eight of 29 GD patients and 8 of 35 HT patients had MVP, while none of the control group and 2 of 20 of the simpl e goiter group had MVP (p < 0.05). ANA were detected at low titers in 5 of 8 in MVP(+) GD versus 3 of 21 in MVP(-) GD (p < 0.05). In the HT group the MVP(+) patients had a significantly higher incidence of ANA and ENA, 5 of 8 and 2 of 8 versus 5 of 27 and 0 of 27 of MVP(-) patients, respectively, p < 0.05. A statistically significant higher incidence of aCL was found in HT MVP(+) patients. (3/8) versus HT MVP(-) 1/27, p < 0.05. RF levels (immunog lobulin A [IgA]) were significantly higher in MVP(+) patients. The associat ion of MVP with nonorgan-specific autoantibodies indicates that MVP may als o be an autoimmune disease. It is possible that patients with AITD who also have MVP may be at an increased risk to develop systemic autoimmunity.