BACKGROUND: Mixed connective tissue disease (MCTD) is a distinct autoimmune disease with overlapping features of different connective tissue diseases and a broad spectrum of presentation and prognosis. Our aim is to present the clinical profile of a cohort of Filipinos with MCTD.
METHODS: Charts with diagnosis of MCTD based on the Alarcon-Segovia Criteria from the Philippine General Hospital Adult Rheumatology clinic from January 1999 to December 2011 were reviewed for demographics, clinical presentation, and management. Descriptive statistics were applied.
RESULTS: Fourteen patients were identified to have MCTD. All were females. The median age at symptom onset, and at diagnosis, was 30.5, and 31.5 years, respectively, with two having juvenile onset of symptoms. Mean interval from symptom onset to diagnosis is two years. Patients are being followed up for the past mean of 3.5 years.All eight women    who wanted children were able to conceive, and among them only two had fetal losses but were negative for antiphospholipid antibodies. Chief complaint was most commonly joint pain (67%) followed by skin tightness (13%). Systemic lupus erythematosus (SLE) was the most frequent initial diagnosis (43%). Majority had initial constitutional symptoms with generalized weakness and fatigue being the most frequent (93%). Most common physical findings in different body systems are as follows: musculoskeletal - arthritis (100%); vascular - Raynaud's phenomenon (93%); cutaneous- skin tightness (71%); gastrointestinal - dental caries (57%); hematologic - anemia of chronic disease (50%); cardiopulmonary - accentuated pulmonary component of the second heart sound and right ventricular hypertrophy (21% each); neurologic - peripheral neuropathy (21%); renal - proteinuria (21%); endocrine - autoimmune thyroiditis (21%).Half have anemia of chronic disease. Only three (21%) have proteinuria and were below nephrotic range. Twelve out of 12 have elevated sedimentation rates. For serologic studies, all have speckled ANA  and very  high  titers  of  anti-U1RNP;six of six patients have  normal  rheumatoid  factor(RF) titers; one    out    of  two  have  positive  anti-Ro;two out of four have anti-Ds DNA; none of two have anti-SCL70.Majority of the chest x-rays,electrocardiograms,echocardiographs  were  normal.Three have pulmonary hypertension. One out of four has restrictive lung disease on pulmonary function test. Most are in remission and are on low-dose prednisone (79%), hydroxychloroquine (50%), nifedipine (36%) and methotrexate (21%).
CONCLUSION: This is the first study that detailed clinical and laboratory features of Filipinos with MCTD diagnosed using the Alarcon-Segovia criteria. Most clinical features, disease activity, and management are concordant with international data. Possible peculiarities include fewer interstitial lung disease, esophageal dysmotility, thrombocytopenia and leucopenia, and RF titers. We intend to add newly diagnosed patients and pursue this cohort for us to better understand the course of MCTD in Filipinos that could translate to better patient care.