Association of Autoimmune Diseases With Down Syndrome

Abstract

BACKGROUNDDown syndrome (DS) is a genetic disease with trisomy of chromosome 21, associated to a higher prevalence of autoimmune disorders. However, the presence of rheumatic diseases in patients with this trisomy is unusual. This case describes a patient with DS diagnosed with mixed connective tissue disease (MCTD), characterized by overlapping symptoms of more than one collagenous disease. CASE REPORTA 39-year-old woman previously diagnosed with DS and hypothyroidism came to the clinic reporting that 2 years ago she started showing hypopigmentation, thickening, skin dryness, with difficulty to walk. She also reported myasthenia, difficulty moving her hands and mouth, and arthralgia in small and large joints. Physical exam showed hypo/achromic macules on lower and upper limbs, with leukomelanoderma, violaceous peripalpebral lesion, diffuse skin thickening and alopecia. Raynaud's phenomenon, telangiectasis, synovitis on the wrists, thinning of the distal phalanges and sclerodactyly were observed. Tests showed ANA (1:320) with a mixed nucleolar and fine dotted nuclear pattern, negative anticardiolipin, CH50 (137.2), anti-DNA, anti-SM, anti-RO, anti-LA, anti-SCL-70, antibeta-2-GPI, anticentromere, lupus anticoagulant, C-ANCA, and atypic ANCA were not reagent, anti-RNP (45.4), antimyeloperoxidase (359), and P-ANCA (1/40) were reagent. In addition, she presented normocytic anemia and leukopenia. ESR, CRP, and CPK were high. Therefore, an echocardiogram, hand and wrist X-rays, upper digestive endoscopy, high-resolution computed tomography (HRCT), and muscle enzymes were requested due to the suspicion of CTED or ES. On her return, she reported cough with sputum and presented an echocardiogram with moderate pericardial effusion without signs of diastolic restriction and a pulmonary artery systolic pressure of 33 mmHg. X-rays of the hands with amorphous calcifications of mottled soft tissue in the distal third of the first right clinodactyly and distal and middle third of the left. X-rays of the right wrist without changes and of the left wrist with amorphous hyperdense material in the carpal bones and calcification in soft tissue adjacent to the ulna. HRCT suggestive of tuberculosis. In view of this, investigation for infectious disease was initiated. CONCLUSIONMCTD is a multifaceted disease, requiring careful investigation. In this case, the diagnosis was built from the clinical picture associated with a positive anti-RNP in the absence of other specific antibodies for SLE and ES. However, since there are few reports that address a patient with DS and MCTD, this case is important to make professionals aware of this connection that may be present in clinical practice.