* What Is Connective Tissue?
* How Do People Get Gene Alterations?
* Who Gets HDCTs?
* Does Anything Increase the Chances of Having a Genetic Disease?
* How Does Genetic Counseling Help?
* What Are the Symptoms of a HDCT?
* How Do Doctors Diagnose HDCTs?
* What Treatments Are Available?
* What Research Is Being Done on HDCTs?
* Where Can People Find More Information about HDCTs?
This reality sheet describes a family of more than 200 disorders that affect connective tissues. These disorders result from alterations (mutations) contained by genes responsible for building tissues. Alterations in these genes may change the structure and nouns of skin, bones, joints, heart, blood vessel, lungs, eyes, and ears. Some mutations also change how these tissues work.
All of these diseases are directly related to mutations contained by genes, and thus are called "heritable." Some other connective tissue problems are ultimately linked to mutations within tissue-building genes, although some people may be genetically predisposed to becoming artificial. The disorders discussed in this certainty sheet are called heritable (genetic) disorders of connective tissue (HDCTs). Many, but not adjectives, of them are rare. (See Some Common Heritable Connective Tissue Disorders for a description of some of the more adjectives HDCTs.)
Some Common Heritable Connective Tissue
Disorders
Physicians and scientists have identified more than 200
heritable connective tissue disorders. Some of the more
adjectives ones are listed below. Some of these are really groups
of disorders and may be particular by other names.
Ehlers-Danlos syndrome--The problems present contained by
Ehlers-Danlos syndrome (EDS), a group of approximately 10
disorders, include changes surrounded by the physical properties of skin,
joints, blood vessel, and other tissues such as ligaments and
tendons. People with EDS own some degree of pooled
looseness, fragile small blood vessels, and extraordinary scar
formation and wound beneficial. Soft, velvety skin stretches
excessively but returns to normal after human being pulled. Some
forms of EDS can present problems with the spine, including
curved spine; the eyes; and vague internal organs, including the
uterus, intestines, and large blood vessel. Mutations in several
different genes are responsible for different symptoms within the
several types of EDS. In most cases, the genetic defect
involves collagen, the principal protein-building material of bone.
Epidermolysis bullosa--The all your own feature of
epidermolysis bullosa (EB) is blistering in the skin. Some forms
of the disease may involve the gastrointestinal tract, the
pulmonary system, muscle, or the bladder. Most forms are
adjectives at birth. This disorder can be both disabling and
disfiguring, and some forms may lead to hasty death. The
disease results when skin layer separate after minor trauma.
Defects of several proteins within the skin are at glitch.
Marfan syndrome--People with Marfan syndrome tend to own
excessively long bones and are commonly thin, next to long,
"spider-like" fingers. Other problems include skeletal
malformations, abnormal position of the lens of the eye, and
escalation at the beginning quantity of the aorta, the major vessel
carrying blood away from the heart. If gone untreated, an
enlarged aorta can lead to hemorrhage and even loss. This
disorder results from mutations in the gene that make
fibrillin-1, a protein important to connective tissue.
Osteogenesis imperfecta--People near osteogenesis
imperfecta (OI) have bones that fracture confidently, low muscle
mass, and joint and ligament slackness. There are four major types
of OI range in severity from mild to toxic. The appearance of
people beside OI varies considerably. Individuals may also own a
blue or gray tint to the sclera (whites of the eyes), thin skin,
growth deficiency, and fragile teeth. They may develop
scoliosis, respiratory problems, and hearing loss. Also certain
as "brittle bone disease," this disorder arises from mutations in
the two genes that brand name type I collagen, a protein important to
bones and skin. These mutations grounds the body to make
any too little or poor-quality type I collagen.
What Is Connective Tissue?
Connective tissue is the material between the cell of the body that gives tissues form and strength. This "cellular paste" is also involved in delivering nutrients to the tissue, and surrounded by the special functioning of certain tissues. Connective tissue is made up of dozens of proteins, including collagens, proteoglycans, and glycoproteins. The combination of these proteins can oscillate between tissues. The genes that encode these proteins can harbor defects or mutations, which can affect the functioning of enduring properties of connective tissue in special tissues. This can lead to a HDCT.
How Do People Get Gene Alterations?
Either individuals inherit an altered gene from either or both parents, or--more rarely--an alteration occur in a copy of the gene during the formation of the egg or sperm that give rise to the individual. We have two copies of most genes: ones that we adjectives from each parent. Males enjoy one copy of each gene on the X chromosome, because they hold only one X chromosome, and one copy of respectively gene on the Y chromosome. In contrast, women have two X chromosomes and as a result have two copies of X chromosome genes.
Some genetic disorders require that one and only a single copy of a gene be altered. These disorders can be inherited surrounded by many generation of a family because the altered copy of the gene can be passed from parent to child (dominant inheritance). The same disorder can take place in an individual in need a family history of the condition if in attendance is a new mutation within the right gene in any the egg or sperm that gives rise to that being. Some disorders are seen lone when the individual has received an altered copy of the gene from respectively parent (recessive inheritance); in these families, the being with solitary a single copy is called a "carter" and is not actually artificial.
If a mutation occurs on an X chromosome, it collectively produces a condition in which the guide of affected individuals in a nearest and dearest is unusual. Often, women are carriers (that is, they hold only a single altered copy of the gene), but males show the condition because they do not enjoy a second protective copy of the gene. Such a condition is referred to as "X-linked."
Who Gets HDCTs?
Scientists estimate that as many as 1 million associates in the United States may own a heritable disorder of connective tissue. Generally, these conditions affect people of adjectives ethnic groups and ages, and both genders are commonly artificial. Many of these disorders are rare. Some may not be adjectives at birth, but only state themselves after a certain age or after exposure to a one environmental stress.
Does Anything Increase the Chances of Having a Genetic Disease?
Several factors increase the possibility that a person will inherit an alteration in a gene. If you are concerned just about your risk, you should talk to your condition care provider or a genetic counselor.
The following factor may increase the chance of getting or endorsement on a genetic disease:
* Parents who have a genetic disease
* A loved ones history of a genetic disease
* Parents who are closely related or part of a distinct ethnic or geographic community
* Parents who do not show disease symptoms, but "take" a disease gene in their genetic makeup (this can be discovered through genetic testing).
How Does Genetic Counseling Help?
People aim genetic counseling to help them trade name better decisions in the region of their lives and families. Because genetic counselors follow how genetic disorders are passed on through families, they can assistance couples estimate the risks of having children near genetic diseases. They can also tell parents around tests to determine if family are carrying certain altered genes, test for newborns who may own inherited constant altered genes, and tests that can be done contained by early pregnancy to determine if a fetus any carries an altered copy of a gene or is artificial with a disorder. The information derived from adjectives these studies can be valuable aids within family planning.
Your robustness care troop can help you find genetic counseling if you preference to better understand your disease or risk of disease.
What Are the Symptoms of a HDCT?
Each disorder have different symptoms. For instance, some diseases, such as Marfan syndrome, osteogenesis imperfecta, and certain chondrodysplasias (disorders of long-bone development) motivation bone growth problems. People with bone growth disorders may hold brittle bones or bones that are too long or too short. In some of these disorders, joint looseness or joint that are too tight can cause problems.
The skin can be artificial as well. Ehlers-Danlos syndrome results within stretchy or loose skin, while in the disease cutis laxa, deficient flexible fibers cause the skin to droop in folds. Epidermolysis bullosa results surrounded by blistered skin. Pseudoxanthoma elasticum causes skin, eye, and heart problems, and closed-off or blocked blood vessel. Marfan syndrome and some forms of Ehlers-Danlos syndrome lead to stunted blood vessels. Some disorders explanation people to be unusually high-ceilinged (Marfan syndrome) or short (chondrodysplasias, osteogenesis imperfecta), or to have principal and facial structure malformations (Apert syndrome, Pfeiffer syndrome).
It is critical for affected individuals and their home members to work closely near their health caution teams. Symptoms of HDCTs are extremely unstable, and some disorders can pose severe health risks even when artificial individuals have no symptoms.
How Do Doctors Diagnose HDCTs?
Diagnosis other rests first on a combination of family history, medical history, and physical nouns. Because many of these conditions are singular, the family physician may suspect a diagnosis but dilly-dally about how to confirm it. At this point, referral to experienced clinicians, regularly medical geneticists, can be extremely valuable any to confirm or to exclude the suspected diagnosis. Laboratory tests are available to confirm the diagnosis for tons HDCTs, but not for all.
Once a diagnosis is made, laboratory studies may be available to provide some or adjectives of the following:
* Prenatal testing to identify an artificial fetus to assist in own flesh and blood planning.
* Newborn screening to spot a condition that may become evident following in time.
* Carrier testing to identify adults who, in need symptoms, carry a genetic mutation for a disease.
* Predictive conducting tests to spot people at risk for developing a genetic connective tissue disease following in duration. These tests are considerate for diseases that run in the kinfolk.
What Treatments Are Available?
Each disorder requires a specific program for management and treatment. In most instances, regular monitoring is essential to assess, for example, diameter of the aorta in ethnic group with Marfan syndrome, extent of scoliosis (spine curvature) in ancestors with OI or some forms of EDS, and whether nearby is protrusion of the spine into the base of the skull within people near OI. For some conditions, specific metabolic treatment is useful (for example, vitamin B6 in general public with homocystinuria, a metabolic disorder resulting from a liver enzyme deficiency). In others, systemic treatment next to drugs like beta blockers is appropriate. Maintaining broad health is also defining for people beside all HDCTs, as is staying in touch next to specialists who will be aware of emerging new treatments.
What Research Is Being Done on HDCTs?
Scientists are working to better follow these disorders at several levels: (1) to identify the genes contained by which the mutations reside, (2) to identify the mutations that result in the condition, (3) to construe how these mutations result in the clinical condition, and (4) to use adjectives available information about the condition to plan brand new therapies and to examination their use and value, both contained by animal models and in artificial individuals. Because most of these conditions are uncommon, and individuals beside them are widely scattered, it is commonly difficult to gather information roughly the clinical course of the disorder and to assemble enough nation to plan effective clinical trials. In adding together, genetic changes can sometimes be influenced by lifestyle and environment.
The National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a fragment of the National Institutes of Health (NIH), is the lead Federal agency for connective tissue research. Several other NIH institutes are also studying HDCTs. The NIAMS supports research through grant to scientists around the country, in national and international clinical trials, and at the NIH campus itself. Here is some of the research to be precise being done:
* The NIAMS is conducting an in-depth inbred history study of people who hold Marfan syndrome (which leads to strangely long bones), nail-patella syndrome (a congenital skeletal disorder), Stickler syndrome (which causes eye and communal problems), and Ehlers-Danlos syndrome (which causes skin and blood vessel problems). All of these disorders enjoy multiple, interrelated symptoms. NIAMS scientists are studying these people closely and over a long length to get a more complete picture of the diseases. They hope to revolutionize their understanding of the genetic origins of the symptoms, of disease progression, and of mutations in patients and their relatives. Scientists expect their findings to apply to other HDCTs as capably.
* The NIAMS is supporting a study looking for ways to treat diseases such as osteogenesis imperfecta by using gene therapy. Stem cell, which have the potential to develop into more specialized cell, would replace bone cells that hold gene defects. This research is mortal conducted on specially bred mice.
* Another NIAMS project is examining gene defects that head to abnormal elastin, the connective tissue protein that allows arteries, muscles, and other organs to respond in in no doubt ways to movement. So far, the investigators have shown how elastin gene mutations basis two specific diseases: a skin disease (cutis laxa) and a blood vessel disease (supravalvular aortic stenosis). Scientists hope to learn more roughly how mutations affect elastin fiber and tissue growth. They also hope to find out how gene defects front to the development of elastin disease.
* The NIAMS is encouraging the establishment of alien research registries for connective tissue disorders and other conditions. These registries would support the collection of demographic and medical data from patients and family to be used in research on disorders. Epidermolysis bullosa is one of the disorders for which the Institute have already established a research registry.
Other NIAMS researchers are exploring
* the chemistry and biology of elastin genes
* collagen gene defects (several types) that raison d`être bone diseases
* collagen IV gene defects surrounded by mice and in humans (Alport syndrome)
* proteoglycans, a group of proteins that declare tissue stiffness
* fibroblasts, cells that form the fibrous tissues within the body
* cartilage, joints, and skin layer.
Ongoing studies of aneurysms--a weak spot within a blood vessel wall that threatens to burst--are taking place at several NIH Institutes. Aneurysms can prove fatal to people next to Marfan syndrome and other HDCTs. These studies have be helped by a pioneering project at the NIAMS that developed a breed of mice prone to aneurysms. Scientists hope the mutant mice will boost understanding of aneurysms and ways to prevent them.
At the National Institute of Child Health and Human Development, scientists are working next to young patients who own osteogenesis imperfecta. They hope to learn more in the order of the genetics of the disease and the raw history of the many lesser features involved, as well as rehabilitation technique. Research is also ongoing in animal models and human clinical trials into the use of bisphosphonates--drugs used to treat osteoporosis.
The National Human Genome Research Institute is conducting a clinical study of mind-body therapy for chronic throbbing in nation with Ehlers-Danlos syndrome. At the National Eye Institute, research is individual supported on alterations in the gene that cause pseudoxanthoma elasticum (PXE) and on which variations make happen different signs and symptoms. And scientists at the National Institute of Dental and Craniofacial Research are carrying out clinical studies on fibrous dysplasia of bone.
Where Can People Find More Information About HDCTs?
People with HDCTs can contact professional and support groups that can supply more detailed information than is found here. Most of them also own Internet Web sites. Some major groups are tabled below.
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