A joint contracture is a fixed tightening of tissues that prevents normal joint movement. People with mcEDS typically have multiple joint contractures at birth (multiple congenital contractures). The most common joint contractures in mcEDS are adducted thumbs and clubfeet.

Joint hypermobility means a joint has a greater range of motion than usual. People with mcEDS may have hypermobility throughout the body (generalized joint hypermobility) or just in the hands and feet (distal joint hypermobility).

A joint is the point where two or more bones connect. Joint instability means the bones of a joint are not held in place securely. This can lead to joint subluxations, dislocations, sprains, and other injuries.

A joint dislocation occurs when two bones at a joint separate completely and are no longer touching. A subluxation is a partial dislocation in which two bones at a joint are out of place but are still touching each other.

Muscle tone is the amount of tension (or resistance to movement) in the muscles. Muscle tone allows us to hold our bodies upright and affects the control, speed, and range of our movement. Muscle hypotonia, or low muscle tone, means the muscles are floppy and unable to properly support the body’s position and movement. It may require more effort for people with hypotonia to move and maintain good posture.

Motor skills are actions that use specific muscle movements to perform a task. Gross motor skills involve large muscle groups, such as rolling, crawling, and walking. Delayed gross motor development means that a child has trouble with gross motor skills that other children their age can do.

It may take people with mcEDS longer to learn to walk, but most people can eventually walk independently.

Bone density is the amount of minerals in the bones. Bones that contain more minerals are denser and stronger. Bones with less minerals are weaker and may be more vulnerable to fractures.

Skin hyperextensibility means the skin can be stretched beyond the normal range.

People with mcEDS often bruise very easily, which may result in the development of hematomas.

People with mcEDS may have fragile skin that is prone to tearing.

Atrophic scars are scars that have widened and become thin, causing them to appear sunken.

Wounds may heal more slowly than usual in people with mcEDS.

A fistula is an abnormal connection between two body parts. Some people with mcEDS have recurrent subcutaneous infections, which can lead to the formation of fistulas around the elbow or hip area.

Scoliosis is a sideways curve in the spine that gives the spine an “S” or “C” shape.

Kyphosis is an abnormal forward curve in the spine that causes the upper back to look more rounded.

Kyphoscoliosis is a combination of two spinal conditions: kyphosis and scoliosis. Kyphosis is an abnormal forward curve in the spine that causes the upper back to look more rounded. Scoliosis is a sideways curve in the spine that gives the spine an “S” or “C” shape.

The spinal cord is part of the nervous system that extends from the brain to the lower back. It carries nerve signals back and forth between the brain and the nerves that run throughout the body.

The spinal cord normally floats freely inside a tube in the spine called the spinal canal. In tethered cord syndrome (TCS), the spinal cord is stuck (tethered) to the inside of the spinal canal. This limits the spinal cord’s movement and causes it to stretch.

Symptoms of tethered cord syndrome include:

• Low back pain
• Leg pain
• Leg weakness or numbness
• Changes in bladder and bowel function
• Tethered cord syndrome has been reported in people with mcEDS, but this is not a common feature.

People with mcEDS may have increased sensitivity to pain (hyperalgesia) in response to pressure. This pain can be severe and may interfere with blood pressure measurement.

The ventricles are a network of cavities in the brain that are filled with cerebrospinal fluid (CSF). Ventricular enlargement means the ventricles are enlarged, often due to a buildup of cerebrospinal fluid.

People with mcEDS often have similar craniofacial features, which include features of the face and the rest of the head.

Craniofacial features of mcEDS include:

• Large soft spot on a baby’s head (large fontanelle)
• Down-slanting eyes (down-slanting palpebral fissures)
• Widely spaced eyes (hypertelorism)
• Small lower jaw (micrognathia)
• Overbite (retrognathia)
• High roof of the mouth (high palate)
• Blue tint to the whites of the eyes (blue sclerae)
• Slender face/protruding jaw
• More space between the nose and upper lip (long philtrum)
• Narrow space between the inner and outer corners of the eye (short palpebral fissures)
• Crowded teeth
• Short nose with an underdeveloped bridge between the nostrils (hypoplastic columella)
• Low-set and rotated ears
• Thin upper lip
• Facial asymmetry
• Flat head shape (brachycephaly)
• Split in the lip or the roof of the mouth (cleft lip or palate)

The sclera (plural: sclerae) is a protective layer of connective tissue that surrounds most of the eye. It is usually white but is more transparent when collagen fibers are thin. This allows the underlying tissue to show through, giving the eyes a bluish color.

Myopia, also called nearsightedness or shortsightedness, is a condition that makes it difficult to see objects that are far away. Due to differences in eye shape, people with myopia can see objects near them more clearly but have trouble seeing objects further away.

Astigmatism is a condition that makes it difficult to see objects at any distance. Due to differences in eye shape, people with astigmatism have blurred or distorted vision.

Hyperopia, also called farsightedness or longsightedness, is a condition that makes it difficult to see objects that are close by. Due to differences in eye shape, people with hyperopia can see objects at a distance more clearly but have trouble seeing objects near them.

Strabismus, also known as crossed eyes, means the eyes do not align to look in the same direction at the same time.

Glaucoma is a condition that can lead to vision loss and blindness. Glaucoma occurs when the optic nerve is damaged, often due to increased pressure in the eye.

The cornea is a clear protective dome that covers the iris and the pupil and allows light to enter the eye. Microcornea refers to a cornea that is smaller than usual, with a diameter of less than 10 mm. Microcornea may cause problems with vision.

The retina is a light-sensitive layer of tissue at the back of the eye. It senses light and sends signals to the brain that allow us to see. Retinal detachment occurs when the retina is pulled away from its normal position at the back of the eye.

Symptoms of retinal detachment include seeing many new floaters, sudden flashes of light, or a dark shadow or curtain covering part of the field of vision. Retinal detachment is a medical emergency that can lead to severe visual impairment, including blindness. Rapid medical treatment is required to preserve vision.

Many people with mcEDS have mild to moderate hearing impairment. This is typically due to sensorineural hearing loss, which occurs when there is a problem with the inner ear or the auditory nerve that delivers sound to the brain.

A hematoma is a large collection of blood outside a blood vessel. It occurs when the wall of a blood vessel is damaged, allowing blood to leak into the surrounding tissue. Hematomas in mcEDS are typically large, progressing, and sometimes critical.

The heart has four chambers separated by valves that open and close to ensure that blood flows in the correct direction. The mitral valve separates the left chambers of the heart.

Mitral valve prolapse (MVP) occurs when the mitral valve is floppy and does not close tightly. This can allow blood to leak back through the mitral valve in the wrong direction, known as mitral valve regurgitation.

Aortic valve regurgitation and tricuspid valve regurgitation have also been reported in mcEDS, but these are far less common.

An atrial septal defect is a hole in the wall (septum) between the upper chambers of the heart (atria). Atrial septal defects allow blood to flow between the atria, which does not usually occur.

Atrial septal defects do not always cause symptoms. However, the heart and lungs must work harder if the hole is large enough. Symptoms of atrial septal defects can include difficulty breathing, shortness of breath with activity, and frequent lung infections.

The aorta is the largest artery in the body. It carries blood away from the heart to the rest of the body. The aortic valve separates the lower left heart chamber and the aorta. Aortic valve regurgitation occurs when the aortic valve doesn’t close tightly, allowing blood to flow backward from the aorta into the heart.

The tricuspid valve separates the right chambers of the heart. Tricuspid valve regurgitation occurs when the tricuspid valve doesn’t close tightly, allowing blood to leak backwards through the valve.

People with mcEDS may have a flat chest or broad chest with widely spaced nipples, sometimes called a shield chest. Poor breast development is also reported in mcEDS.

Pectus excavatum is an indentation in the chest that occurs when the sternum grows inward. This happens when too much connective tissue grows between the ribs and the sternum. Mild pectus excavatum may not cause any problems, but if the indentation is deep enough, it can put pressure on the lungs and heart.

Pectus carinatum is a bump on the chest that occurs when the sternum sticks outward more than usual. This happens when too much connective tissue grows between the ribs and sternum. Pectus carinatum does not usually cause symptoms but can cause shortness of breath when exercising.

Pneumothorax happens when air leaks into the chest cavity and puts pressure on the lung, causing it to collapse.

People with mcEDS may have infrequent or difficult bowel movements.

Some people with mcEDS experience pain in the abdomen, the midsection of the body that contains the gastrointestinal system and other organs.

A hernia occurs when an internal organ pushes through a weak spot in the tissues that support it, creating an outward bulge. mcEDS is associated with umbilical hernias (near the bellybutton) and inguinal hernias (in the groin).

Diverticular disease is a condition that affects the large intestine. Diverticulosis occurs when small, bulging pockets (diverticula) develop in the wall of the large intestine. Diverticulitis occurs when these pockets become infected or inflamed.

A stomach ulcer, also called a gastric ulcer, is an open sore in the lining of the stomach. Stomach ulcers can cause abdominal pain, heartburn, and nausea.

A bowel rupture, or bowel perforation, is a hole in the wall of the small or large intestine. The hole may allow waste to leak into the abdomen, which can cause an infection. Bowel ruptures have been reported in mcEDS but are not a common feature.

Hydronephrosis occurs when urine builds up in the kidney and causes it to swell. Hydronephrosis may affect one or both kidneys.

Urinary retention means it is difficult to empty the bladder completely.

A distended bladder, or bladder dilation, occurs when the bladder becomes enlarged or inflamed. This can occur due to urinary retention.

A urinary tract infection (UTI) is an infection of the urinary system. Symptoms include pain and trouble urinating. Some people with mcEDS experience multiple, recurrent urinary tract infections.

Kidney stones, or nephrolithiasis, are hard masses of minerals and salts that form in the kidneys. Kidney stones can cause pain as they pass through the urinary tract.

Bladder stones, or cystolithiasis, are hard masses of minerals in the bladder that can cause pain and trouble urinating. They usually form when a person has difficulty emptying their bladder.

Undescended testicles, also known as cryptorchidism, means the testicles did not move down into the scrotum before birth. This may affect one or both testicles in mcEDS.

Some people with mcEDS have recurrent infections, including urinary tract infections.

An adducted thumb is a type of joint contracture in which the inside of the thumb rotates inward to face the index finger. Joint contractures limit the normal movement of a joint, which can interfere with functioning. Most people with mcEDS are born with adducted thumbs, which may become milder with age.

Many people with mcEDS have unusual finger shapes. Their fingers may be long and slender and described as tapering or cylindrical. Tapering fingers are thickest at the base and get thinner towards the tip. Cylindrical fingers are roughly the same circumference from base to tip.

People with mcEDS often have extra wrinkles on the palms of their hands. This typically becomes more prominent with age.

Clubfoot (talipes equinovarus) causes the foot to point downward and twist inward. This causes the toes to point toward the opposite leg, which can make walking difficult if not addressed.

Flat feet (pes planus) means the feet have little to no arch when standing. When a person with flat feet stands, the entire bottom of their foot touches the ground.

Pes valgus means the back or heel of the foot bends outward.

Pes cavus means the foot has a high arch that does not flatten when bearing weight.