Mixed connective tissue disease
Encyclopedia
In medicine
, mixed connective tissue disease (also known as "Sharp's syndrome"), commonly abbreviated as MCTD, is an autoimmune disease
, in which the body's defense system
attacks itself. It was characterized in 1972.
It is sometimes equated with the term "Undifferentiated connective tissue disease",) but some sources specifically reject such assertions of equivalence. The term was introduced by Leroy in 1980.
, myositis
, systemic lupus erythematosus
, and rheumatoid arthritis
(with some sources adding polymyositis
, dermatomyositis
, and inclusion body myositis
) and is thus considered an overlap syndrome
.
MCTD commonly causes:
Distinguishing laboratory characteristics are a positive, speckled anti-nuclear antibody
and an anti-U1-RNP antibody.
It has been associated with HLA-DR4
.
The prognosis for MCTD tends to be better than other autoimmune diseases due to lack of renal disease and response to corticosteroids.
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
, mixed connective tissue disease (also known as "Sharp's syndrome"), commonly abbreviated as MCTD, is an autoimmune disease
Autoimmune disease
Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. In other words, the body actually attacks its own cells. The immune system mistakes some part of the body as a pathogen and attacks it. This may be restricted to...
, in which the body's defense system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
attacks itself. It was characterized in 1972.
It is sometimes equated with the term "Undifferentiated connective tissue disease",) but some sources specifically reject such assertions of equivalence. The term was introduced by Leroy in 1980.
Clinical features
MCTD combines features of sclerodermaScleroderma
Systemic sclerosis or systemic scleroderma is a systemic autoimmune disease or systemic connective tissue disease that is a subtype of scleroderma.-Skin symptoms:...
, myositis
Myositis
Myositis is a general term for inflammation of the muscles. Many such conditions are considered likely to be caused by autoimmune conditions, rather than directly due to infection It is also a documented side effect of the lipid-lowering drugs statins and fibrates.Elevation of creatine kinase in...
, systemic lupus erythematosus
Systemic lupus erythematosus
Systemic lupus erythematosus , often abbreviated to SLE or lupus, is a systemic autoimmune disease that can affect any part of the body. As occurs in other autoimmune diseases, the immune system attacks the body's cells and tissue, resulting in inflammation and tissue damage...
, and rheumatoid arthritis
Rheumatoid arthritis
Rheumatoid arthritis is a chronic, systemic inflammatory disorder that may affect many tissues and organs, but principally attacks synovial joints. The process produces an inflammatory response of the synovium secondary to hyperplasia of synovial cells, excess synovial fluid, and the development...
(with some sources adding polymyositis
Polymyositis
Polymyositis is a type of chronic inflammation of the muscles related to dermatomyositis and inclusion body myositis.-Signs and symptoms:...
, dermatomyositis
Dermatomyositis
Dermatomyositis is a connective-tissue disease related to polymyositis and Bramaticosis that is characterized by inflammation of the muscles and the skin.- Causes :...
, and inclusion body myositis
Inclusion body myositis
Inclusion body myositis is an inflammatory muscle disease, characterized by slowly progressive weakness and wasting of both distal and proximal muscles, most apparent in the muscles of the arms and legs...
) and is thus considered an overlap syndrome
Overlap syndrome
An overlap syndrome is an autoimmune disease of connective tissue in which the patient presents with symptoms of two or more diseases. As much as 25% of all patients with connective tissue disease show signs of an overlap syndrome....
.
MCTD commonly causes:
- joint pain/swellingArthritisArthritis is a form of joint disorder that involves inflammation of one or more joints....
, - malaiseMalaiseMalaise is a feeling of general discomfort or uneasiness, of being "out of sorts", often the first indication of an infection or other disease. Malaise is often defined in medicinal research as a "general feeling of being unwell"...
, - Raynaud phenomenon,
- Sjögren's syndromeSjögren's syndromeSjögren's syndrome , also known as "Mikulicz disease" and "Sicca syndrome", is a systemic autoimmune disease in which immune cells attack and destroy the exocrine glands that produce tears and saliva....
, - muscle inflammationMyositisMyositis is a general term for inflammation of the muscles. Many such conditions are considered likely to be caused by autoimmune conditions, rather than directly due to infection It is also a documented side effect of the lipid-lowering drugs statins and fibrates.Elevation of creatine kinase in...
, and - sclerodactylySclerodactylySclerodactyly is a localized thickening and tightness of the skin of the fingers or toes. Sclerodactyly is commonly accompanied by atrophy of the underlying soft tissues....
(thickening of the skin of the pads of the fingers)
Distinguishing laboratory characteristics are a positive, speckled anti-nuclear antibody
Anti-nuclear antibody
Anti-nuclear antibodies are autoantibodies directed against contents of the cell nucleus....
and an anti-U1-RNP antibody.
It has been associated with HLA-DR4
HLA-DR4
HLA-DR4 is a HLA-DR serotype that recognizes the DRB1*04 gene products. The DR4 serogroup is large and has a number ofmoderate frequency alleles spread over large regions of the world.-Serology:The serological identification of DR4 is good...
.
The prognosis for MCTD tends to be better than other autoimmune diseases due to lack of renal disease and response to corticosteroids.