Connective tissue dysplasia

The name "connective tissue dysplasia" covers a wide range of disorders. These disorders are caused by defects in the connective tissues such as bone, ligaments, tendons and skin. There is a clinical service which specializes in the multidisciplinary management of these conditions including rehabilitation, physiotherapy and occupational therapy as well as specific genetic diagnosis at the Children’s Hospital at Westmead campus.

Children with these disorders may have:

• too much joint movement (hypermobility)
• not enough joint movement (joint contractures)
• excessive laxity (looseness) of skin or
• fragile bones, fragile skin, blood vesssels or ligaments

The disorders can be variable because many affected people have a mixture of these different symptoms.

Most connective tissue dysplasias follow common patterns of inheritance. These patterns can help genetic counsellors to provide families with information about inheritance in their family.

There are similarities between the disorders, so that discoveries from research in to one disorder are often of great help in understanding and treating another disorder.

Kinds of disorders

The disorders can be grouped into:

• Arthrogryposis and related disorders
• Ehlers-Danlos Syndrome and familial hypermobility
• Marfan Syndrome and related disorders
• Mucopolysaccharidoses
• Skeletal Dysplasias
• Osteogenesis Imperfecta.

Arthrogryposis and related disorders

Decreased joint movement is present at birth and in the most severe cases, virtually all joints are affected. However, in most people with Arthrogryposis, only some joints are affected. The aim of rehabilitation is to restore normal function and develop each individual's potential. All these disorders need to be actively managed with therapy from birth.  

This group includes over 200 disorders, in three major subgroups:

• Amyoplasia, where there is a lack of muscle development in most areas and
• Distal arthrogryposis which involves mainly the hands and feet (distal).
• Joint contractures with other features e.g. learning difficulties, muscle weakness, nervous system involvement.

Ehlers-Danlos Syndrome

There are multiple disorders known as Ehlers-Danlos syndromes (<?xml:namespace prefix = st1 />EDS).  These all have some degree of hypermobile joints (very loose joints) from birth and throughout life.  Some people may have fragile skin (classic type), and a tendency to sprains, while others have fragile blood vessels with a tendency to bruising or blood vessel rupture. Rarely the corneas of the eyes are brittle and this may result in visual loss.

There may be deformities of the spine such as scoliosis, or joint contractures due to dislocation of joints with damage to nearby muscles.

Rehabilitation goals include prevention of trauma to skin, blood vessels and eyes, protection of loose joints, and treatment of specific complications.

The “Hypermobility Syndrome” refers to the finding that people with joint hypermobility from any cause have an increased chance of developing

• Fatigue which may be severe and disabling
• Joint and muscle pain which is sometime known as fibromyalgia.

The Hypermobility Syndrome requires a specific program of management to avoid long term disability and incorrect treatment as the particular type of joint and muscle pain is resistant to convential pain medicines.

Marfan Syndrome and related disorders

The Marfan Syndrome is associated with tall stature and long arms and legs. There is an increased risk of visual disability in childhood and blood vessel rupture in adult life. Marfan syndrome has multiple different but related genetic disorders. People with Marfan Syndrome usually have very loose joints, but some people have very tight joints and ligaments. A special group have the related disorder, Loeys-Dietz Syndrome.

Marfan syndrome and related disorders need regular health and heart checkups to avoid complications.

Mucopolysaccharidoses (MPS)

These are caused by lysosomal enzyme deficiencies. The body does not produce any, or very little enzyme, so complex sugars are stored in the body cells instead of being broken down and recycled by the body to maintain health and normal growth. These complex sugars are called polysaccharides.

The MPS disorders are progressive, although progression may be slow. Some children have progressive storage  of polysaccharides in the brain, which can result in significant intellectual and behavioural impairment.

Most children with various types of MPS have very tight joints (joint contractures), but some have very loose joints and require specific multidisciplinary management.

Skeletal Dysplasias

There are about 400 disorders in this group. They are generally diagnosed from a combination of expert clinical examination and specific features seen on x-ray of the skeleton. They affect bone (bone dysplasias) and/or cartilage (chondrodysplasias).

Most result in very short stature, such as in Achondroplasia, but some have average or tall stature. Intelligence is normal. Where short stature is present there are different patterns with some people having normal sitting height and short limbs and others with a short trunk. Joints may be either contracted or hypermobile. Some people have congenital heart defects, visual disabilities, cleft palate, or extra fingers and toes. Each disorder or group of disorders has specific requirements for management. 

Osteogenesis Imperfecta (OI)

People with OI have very fragile bones. There are different types of OI and a wide range in severity from person to person.   In some people with OI, the whites of the eyes, known as sclerae, appear very blue.   People with OI may be very short and some develop severe deformity of the limbs and/or spine. Teeth may also be fragile. Some affected individuals develop deafness in later life. Children with OI need highly specialized assessment and treatment.

Other connective tissue dysplasias

There are at least 600 disorders generally grouped together as the Connective Tissue Dysplasias. These include extremely rare disorders such as Pseudoxanthoma Elasticum and common disorders such as familial hip dysplasia.

*Advice about diagnosis and management of any of these conditions can be sought through your local genetic service and advice on referral to the statewide multidisciplinary management service.

• A genetic counsellor will provide you with information about inheritance in your family.