Mixed Connective Tissue Disease (MCTD)

Mixed connective tissue disease (MCTD) is a rare systemic autoimmune disease characterized by high levels of anti-U1 ribonucleoprotein (U1-RNP) antibodies and overlapping features of several connective tissue diseases, most commonly systemic lupus erythematosus, systemic sclerosis (scleroderma), and polymyositis. Symptoms often develop gradually over time and may include Raynaud’s phenomenon, swollen fingers, joint pain, muscle inflammation, and fatigue. Although MCTD shares features with several autoimmune diseases, it is considered a distinct clinical diagnosis with its own classification criteria.

Red/reddish-brown rash patches over the knuckles, increased fatigue/mild fever, Raynaud’s phenomenon (cold/numb fingers/toes), swelling of the fingers or hands, muscle and joint pain/swelling/deformities, organs (kidneys, heart, and lungs) can be afflicted later in the progression of the disease, chest pain, stomach inflammation, dyspnea (trouble with breathing), high erythrocyte sedimentation rate, and dry mouth/eyes.

Rheumatoid arthritis, Sjogren’s syndrome, systemic lupus erythematosus, scleroderma, and polymyositis. 

While MCTD can develop in anyone, females under the age of 50 are most commonly afflicted.

• Subacute cutaneous lupus erythematosus in a patient with mixed connective tissue disease (2023)
• 2019 diagnostic criteria for mixed connective tissue disease (MCTD): From the Japan research committee of the minitry of health, labor, and welfare for systemic autoimmune diseases (2021)
• Clinical and immunological profile of mixed connective tissue disease and a comparison of four diagnositic criteria (2020)
• Epigenome-wide comparative study reveals key differences between mixed connective tissue disease and related systemic autoimmune diseases (2019)

Presha’s Story: Being Okay with Not Being Okay

Claire’s Story: Gender Bias & The Long Road to Diagnosis

Rahel’s Story: MCTD, Raynaud’s, & Living with Gratitude