A List of Genetic Connective Tissue Disorders

Genetic connective tissue disorders are conditions people are born with, caused by changes in the genes that build the body’s support proteins, such as collagen, elastin and fibrillin. The best known are Marfan syndrome, the Ehlers-Danlos syndromes, Loeys-Dietz syndrome, osteogenesis imperfecta, Stickler syndrome, Alport syndrome, cutis laxa, pseudoxanthoma elasticum and epidermolysis bullosa. Which protein is affected largely decides which body parts are at risk, from joints and skin to arteries, eyes, bones and kidneys.

More than 200 conditions affect connective tissue, but only some are inherited; others, like lupus, are autoimmune.1MedlinePlus. Connective Tissue Disorders The inherited ones can look very different from each other, because each damaged protein shows up in the tissues that rely on it most. Some mainly cause bendy joints or fragile skin, while a few quietly put the body’s largest artery at risk.

The Main Genetic Connective Tissue Disorders at a Glance

The body’s supporting matrix is built from fibre-forming proteins such as collagens and elastin, plus other molecules that hold water and bind cells together.2PubMed. The extracellular matrix as a multitasking player in disease Fibrillins and related proteins form fine threads that give tissues stretch and strength.3Nature. Extracellular Matrix Proteins in Connective Tissue Disorders A faulty gene for any one of these proteins can weaken skin, joints, vessels, bone or eyes, depending on where that protein is used.4PubMed. The extracellular matrix as a multitasking player in disease

If a doctor has named one condition, find its protein first, since the protein helps show which organs need checking. Gene names on a test report may match the entries above, though many other genes can be involved.

Flexible joints alone are not a diagnosis, since many healthy people are very bendy. A connective tissue disorder involves a pattern across skin, joints, vessels or other organs, and a family history or those added features are what push doctors toward testing.

How a Faulty Gene Weakens Tissue

Some gene changes simply reduce how much of a support protein is made, leaving the matrix thin.15PubMed Central. Genetic Disorders of the Extracellular Matrix Others produce a misshapen protein that interferes with the normal copy, which can be more damaging.16PubMed Central. Genetic Disorders of the Extracellular Matrix In classic Ehlers-Danlos, most cases come from one working copy of a type V collagen gene going silent.17PubMed. Clinical and genetic aspects of Ehlers-Danlos syndrome, classic type Collagen fibres in skin, joints, eyes and vessels need both copies to form properly.18PubMed Central. COL5A1 haploinsufficiency is a common molecular mechanism underlying the classical form of EDS

We inherit two copies of most genes, one from each parent, and many of these disorders appear when just one copy is faulty. In dominant conditions like these, an affected parent has about a 1 in 2 chance of passing the change to each child.

Some conditions are recessive. Pseudoxanthoma elasticum needs two faulty ABCC6 copies, and carriers with a single copy show no signs, as studies of carriers found.19PubMed. Pseudoxanthoma elasticum: Wide phenotypic variation in homozygotes and no signs in heterozygotes for the c.3775delT mutation in ABCC6 The parents of an affected child are often both unaffected carriers.

Marfan Syndrome and Loeys-Dietz Syndrome

Fibrillin-1 threads also store a growth signal, keeping it inactive until it is needed.20Learn.Genetics. A List of Genetic Connective Tissue Disorders That signal helps control muscle and bone growth.21Learn.Genetics. A List of Genetic Connective Tissue Disorders When fibrillin is faulty, the signal is released in the wrong places or at the wrong times.223billion. FBN1 Gene Variants: Why One Mutation Causes Marfan Syndrome The extra signal drives scarring, matrix breakdown and inflammation that worsen the aorta.233billion. FBN1 Gene Variants: Why One Mutation Causes Marfan Syndrome

In daily life, Marfan typically means a tall frame with long limbs and fingers. A displaced lens can blur vision. Widening of the aorta often causes no symptoms at all and is found only on a scan.

Loeys-Dietz reaches the same signal from the other end: it comes from changes in genes for the signalling pathway itself.24PubMed Central. Activation of TGF-β signaling in an aortic aneurysm in a patient with Loeys-Dietz syndrome caused by a novel loss-of-function variant of TGFBR1 Changes in TGFBR1 and TGFBR2 are linked to aggressive aneurysms and early tearing, so close monitoring and planned repair are advised.25Academic Medicine & Surgery. Acute Aortic Dissection in Heritable Thoracic Aortic Disease: Loeys–Dietz Syndrome with TGFBR2 Mutation Compared with Marfan, arteries beyond the aorta can be involved, and problems can appear at younger ages.

The Ehlers-Danlos Syndromes, Including Vascular and Hypermobile Types

The 13 types share loose joints, stretchy skin and fragile tissues.26PubMed. The 2017 international classification of the Ehlers-Danlos syndromes Most trace to collagen genes or to genes for enzymes that process collagen.27PubMed. The 2017 international classification of the Ehlers-Danlos syndromes

Hypermobile Ehlers-Danlos is the commonest type, and no gene has yet been found for it.28PubMed. Hypermobile Ehlers-Danlos syndrome: A review and a critical appraisal of published genetic research to date It is therefore diagnosed on clinical criteria rather than a blood test.29PubMed. Hypermobile Ehlers-Danlos syndrome: A review and a critical appraisal of published genetic research to date Even so, in one group meeting those criteria, gene testing found a different or extra diagnosis in about 1 in 4.30PubMed Central. Hypermobile Ehlers–Danlos Syndrome: Diagnostic Challenges and the Role of Genetic Testing Testing can still matter, because some of those diagnoses need different care.31PubMed Central. Hypermobile Ehlers–Danlos Syndrome: Diagnostic Challenges and the Role of Genetic Testing Day to day, hypermobile type brings frequent joint sprains and dislocations, and physical therapy aims first at protecting and stabilising the joints.

Vascular Ehlers-Danlos is the serious exception. It comes from changes in the type III collagen gene and causes fragile arteries and organs and early death.32PubMed. Vascular Ehlers-Danlos Syndrome: Long-Term Observational Study In the US it affects roughly 1 in 50,000 to 1 in 200,000 people.33PubMed Central. Vascular Ehlers-Danlos Syndrome: A Comprehensive Natural History Study in a Dutch National Cohort of 142 Patients Its hallmark emergencies are sudden artery tears, bowel rupture and uterine rupture.34PubMed Central. Vascular Ehlers-Danlos Syndrome: A Comprehensive Natural History Study in a Dutch National Cohort of 142 Patients

Worth mentioning to a doctor: thin skin with visible veins and easy bruising, or a relative who had an arterial tear or bowel rupture young. Sudden severe pain in the belly, chest or back needs emergency care.

Bone, Eye, Ear and Kidney Disorders

Osteogenesis imperfecta comes mostly from type I collagen gene changes, causing breakable bones and blue-tinged eye whites.35PubMed Central. Splice receptor-site mutation c.697-2A>G of the COL1A1 gene in a Chinese family with osteogenesis imperfecta Stickler syndrome affects the collagen of the eye’s gel and of cartilage.36PubMed. Stickler syndrome and the vitreous phenotype: mutations in COL2A1 and COL11A1 That can bring severe nearsightedness from birth, retinal detachment, cleft palate, hearing loss and early arthritis.37PubMed. Stickler syndrome and the vitreous phenotype: mutations in COL2A1 and COL11A1

Stickler is often missed because signs vary widely, even within one family.38PubMed. Stickler syndrome and the vitreous phenotype: mutations in COL2A1 and COL11A1 A child with a cleft palate and strong glasses may have it. Regular eye checks matter because retinal detachment can cause blindness.39PubMed. Stickler syndrome and the vitreous phenotype: mutations in COL2A1 and COL11A1

Alport syndrome affects type IV collagen in the filter membranes of the kidney, inner ear and eye.40PubMed. Proteinuria, eGFR Decline, and the Pathway to Kidney Failure in Alport Syndrome In the kidney, protein leaks into the urine and filtering declines, which can lead to kidney failure.41PubMed. Proteinuria, eGFR Decline, and the Pathway to Kidney Failure in Alport Syndrome Monitoring uses urine tests to look for leaking protein and blood tests to track filtering, with hearing tests as part of follow-up.

Skin-Centred Disorders

Elastin gene changes can cause cutis laxa, sometimes with severe lung disease.42PubMed. Autosomal dominant cutis laxa with severe lung disease: synthesis and matrix deposition of mutant tropoelastin The skin looks loose and sagging, as if prematurely aged. In pseudoxanthoma elasticum, missing ABCC6 protein lets calcium build up in elastic tissue of skin, eyes and vessels.43PubMed Central. Pseudoxanthoma elasticum It shows as small yellowish bumps on the neck and skin folds, and signs vary widely even among people with the same gene change.44PubMed. Pseudoxanthoma elasticum: Wide phenotypic variation in homozygotes and no signs in heterozygotes for the c.3775delT mutation in ABCC6

Dystrophic epidermolysis bullosa comes from faulty type VII collagen, which anchors outer skin to the layer below.45PubMed Central. Dystrophic epidermolysis bullosa: a review Without that anchor, skin blisters and tears with minor friction, so everyday rubbing can raise blisters.

Yellowish bumps on the neck or in skin folds call for an eye and heart check, since pseudoxanthoma elasticum can damage the retina and its deposits in vessels can affect circulation.

Genetic Versus Autoimmune Connective Tissue Disease

Hereditary disorders come from a gene change present at birth.46University of Miami Health System. Hereditary Connective Tissue Disorders Autoimmune and inflammatory ones, such as lupus or scleroderma, usually begin later in life.47Sequence MD. High-Level Guide to Genetic Connective Tissue Disorders Autoimmune diseases also involve the immune system attacking the body, which is why blood tests for inflammation help with lupus but not with Marfan or Ehlers-Danlos.

Lifelong flexibility or a family pattern can point toward a genetic cause, while new joint swelling, rashes or fatigue in adulthood can point toward an autoimmune one, though only a proper assessment can tell them apart. The specialists differ too: geneticists for the first, rheumatologists for the second.

Monitoring the Aorta and When Surgery Comes Up

Widening at the start of the aorta is measured by scan. In Marfan, European guidelines advise surgery at 50 mm, or 46 to 50 mm with a family history of tearing, growth over 2 mm a year, severe valve leaks or planned pregnancy.48PubMed Central. Genetic Basis, New Diagnostic Approaches, and Updated Therapeutic Strategies of the Syndromic Aortic Diseases: Marfan, Loeys–Dietz, and Vascular Ehlers–Danlos Syndrome In Loeys-Dietz, surgery is advised earlier, above 42 mm, because tissue is especially fragile.49PubMed Central. Genetic Basis, New Diagnostic Approaches, and Updated Therapeutic Strategies of the Syndromic Aortic Diseases: Marfan, Loeys–Dietz, and Vascular Ehlers–Danlos Syndrome In vascular Ehlers-Danlos, there is no agreed size cutoff.50PubMed Central. Genetic Basis, New Diagnostic Approaches, and Updated Therapeutic Strategies of the Syndromic Aortic Diseases: Marfan, Loeys–Dietz, and Vascular Ehlers–Danlos Syndrome

A surveillance visit usually involves an echocardiogram, sometimes a CT or MRI. Results are compared with earlier scans to judge growth, so bring prior reports when changing doctors.

Vascular type is handled differently because arteries can tear without much widening. Care focuses on avoiding strain and responding quickly in an emergency, and surgery itself carries extra risk in such fragile tissue.

Genetic Testing and Who Should Get It

After a neck artery tear without other signs, routine gene screening rarely finds a connective tissue disorder.51PubMed Central. Hereditary connective tissue disorders in unselected patients with spontaneous cervical artery dissection: a targeted next generation sequencing approach and systematic review Testing is best reserved for people with a family history of artery tears or tears in several vessels.52PubMed Central. Hereditary connective tissue disorders in unselected patients with spontaneous cervical artery dissection: a targeted next generation sequencing approach and systematic review Gene testing in pregnancy can also identify conditions that affect pregnancy care.53PubMed Central. Ehlers–Danlos syndrome and other heritable connective tissue disorders that impact pregnancies can be detected using next-generation DNA sequencing

Before testing, ask which genes the panel covers, how an unclear result will be handled, and whether relatives should be tested if a change is found.

Pregnancy With a Connective Tissue Disorder

Vascular Ehlers-Danlos carries the highest risk of maternal death, mainly from artery, uterine or bowel rupture.54PubMed Central. Pregnancy Outcomes in Women With Vascular Ehlers-Danlos Syndrome: A Systematic Review of Maternal and Fetal Complications Recent studies report lower death rates thanks to specialist team care and earlier diagnosis.55PubMed Central. Pregnancy Outcomes in Women With Vascular Ehlers-Danlos Syndrome: A Systematic Review of Maternal and Fetal Complications Ehlers-Danlos pregnancies also see more early waters breaking, severe tears and placenta problems.56PubMed Central. Pregnancy Outcomes in Women With Vascular Ehlers-Danlos Syndrome: A Systematic Review of Maternal and Fetal Complications Planning pregnancy with a specialist team before conceiving is wise. Preparation means getting a baseline aortic scan, choosing a hospital with high-risk obstetric care, and discussing the delivery method early.

Treatments on the Horizon

Today care targets complications such as aortic repair, fracture care and physical therapy. New approaches include gene replacement, skipping faulty gene sections and editing DNA or RNA.57PubMed Central. En route towards a personalized medicine approach: Innovative therapeutic modalities for connective tissue disorders Gene editing has shown early promise in raising collagen production in studies.58PubMed Central. Gene editing for collagen disorders: current advances and future perspectives These remain experimental, so ask about clinical trials rather than expecting them in routine care.

The genetics clinic can point you to registries, and patient organisations track trials by condition. Be wary of clinics selling unproven gene therapy.