Mixed connective tissue disease

What it is

From: Orphanet

Mixed connective tissue disease (MCTD) is a rare connective tissue disorder combining clinical features of systemic lupus erythematosus (SLE), systemic sclerosis (SSc), polymyositis (PM) and/or rheumatoid arthritis (RA).

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Arthritis · Very frequent (99-80%)

Inflammation of a joint.

Autoimmunity · Very frequent (99-80%)

The occurrence of an immune reaction against the organism's own cells or tissues.

Chest pain · Very frequent (99-80%)

An unpleasant sensation characterized by physical discomfort (such as pricking, throbbing, or aching) localized to the chest.

Dyspnea · Very frequent (99-80%)

Difficult or labored breathing. Dyspnea is a subjective feeling only the patient can rate, e.g., on a Borg scale.

Elevated erythrocyte sedimentation rate · Very frequent (99-80%)

An increased erythrocyte sedimentation rate (ESR). The ESR is a test that measures the distance that erythrocytes have fallen after one hour in a vertical column of anticoagulated blood under the influence of gravity. The ESR is a nonspecific finding. An elevation may indicate inflammation or may be caused by any condition that elevates fibrinogen.

Fatigue · Very frequent (99-80%)

A subjective feeling of tiredness characterized by a lack of energy and motivation.

Gastritis · Very frequent (99-80%)

The presence of inflammation of the gastric mucous membrane.

Gastroesophageal reflux · Very frequent (99-80%)

A condition in which the stomach contents leak backwards from the stomach into the esophagus through the lower esophageal sphincter.

Myalgia · Very frequent (99-80%)

Pain in muscle.

Pulmonary fibrosis · Very frequent (99-80%)

Replacement of normal lung tissues by fibroblasts and collagen.

Scleroderma · Very frequent (99-80%)

A chronic autoimmune phenomenon characterized by fibrosis (or hardening) and vascular alterations of the skin.

Skin rash · Very frequent (99-80%)

A red eruption of the skin.

Anti-Ro52/TRIM21 antibody positivity · Frequent (79-30%)

The presence of autoantibodies (immunoglobulins) in the blood circulation that react against Ro52/TRIM21.

Anti-U1 ribonucleoprotein antibody positivity · Frequent (79-30%)

The presence autoantibodies in the serum that react to proteins (70 Kd, A, C) that are associated with U1 RNA and form U1snRNP.

Other findings in the same source

From: Orphanet

Additional reported features include Anti-cyclic citrullinated peptide antibody positivity (Frequent (79-30%)); Anti-dsDNA antibody positivity (Frequent (79-30%)); Anti-ribosome Po antibody positivity (Frequent (79-30%)); Arthralgia (Frequent (79-30%)); Edema of the dorsum of hands (Frequent (79-30%)); Fever (Frequent (79-30%)); Increased circulating immunoglobulin concentration (Frequent (79-30%)); Keratoconjunctivitis sicca (Frequent (79-30%)); Myositis (Frequent (79-30%)); Pleuritis (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Adolescent; Adult; Childhood

Inheritance in the source

From: Orphanet

Multigenic/multifactorial

Frequency and the population described

From: Orphanet

Annual incidence: 1-9 / 1 000 000; Norway; Value and class. Point prevalence: 1-9 / 100 000; Norway; Value and class. Point prevalence: 1-9 / 100 000; Japan; Value and class. Annual incidence: 1-9 / 100 000; United States; Value and class.

Which doctor should you see?

The suggested department for discussing Mixed connective tissue disease is Rheumatology, with a rheumatologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Are the findings inflammatory, structural or due to another mechanism?
• Is there evidence that other organs need assessment?
• How will function and any treatment-related risks be monitored?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Mixed connective tissue disease. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.