Parents Against Injustice

Osteogenesis Imperfecta (OI) is a genetic disorder of collagen, a protein which forms the framework for the bone structure. In OI the collagen may be of poor quality, or there may just not be enough to support the mineral structure of the bones. This makes the bones weak and fragile and results in the bones being liable to fracture at anytime even without trauma.

Each time a bone is broken and set it will heal in a position slightly less than perfect and the same bone may often break repeatedly.

As the composition of collagen in the bone is not correct, even when there are no fractures there will be other problems connected to the condition.

Genetic Inheritance of Osteogenesis Imperfecta

In most cases one parent carries the gene for OI and there is a 50% chance that a child will have the condition. In the following diagram the gene marker for OI is represented as A.

Inheritance chart

Despite the shared gene A the condition may affect the Mother, Child 1 and Child 3 in very different ways e.g. the Mother may have few or no symptoms of the condition, Child 1 may have relatively few fractures and child 3 may have dozens or hundreds of fractures and severe mobility problems through their life. DNA testing is available in cases where this pattern of inheritance is not evident.

Genetic counseling is available to families with OI, or who are concerned about the possibility of future children having the condition. Your GP or clinical specialist should be able to refer you directly but should you have a problem accessing a counseling service please contact the BBS.

For a list of Genetic Councilling available in the UK go to Directory of Genetic Centres and Services website at www.gig.org.uk/services.htm.

Osteogenesis Imperfecta

OI is generally subdivided into Types. Not everyone will know what type they are and there is no such thing as a ‘typical person’ within the types. The main types are as follows

Type I

This is the mildest form of the disorder. However, the number of fractures varies greatly. Hypermobility (bendy joints) is common. Spinal issues may be apparent and regular monitoring will be necessary. Hearing problems can affect some (usually becoming evident in early twenty’s), Dentinogenesis Imperfecta (where the teeth crumble, and are brittle) might be evident.

A Child with Type 1 OI

May appear clumsy as hypermobility may increase the chance of falling/tripping

In most cases mainstream schools will be appropriate

May tire more easily than others of their age

Surgery may be required

At times mobility problems may be an issue, short-term use of a wheelchair may be required

An Adult with Type 1 OI

Will generally appear physically in good health. This can lead to problems in people misunderstanding the condition

Might find as they get older that fractures sustained months or years before, have an effect on their day to day mobility

May find that they have fractures more frequently

Type II

Type II is the most severe form of OI. Babies tend not to survive beyond the first few months.

Problems with the bones in the rib cage can lead to the lungs not being fully formed. Often this leads to respiratory complications.

Parents may have been informed of problems at an ante-natal scan, but may have had no warning that their baby has OI

Support needs to be immediate and ranges from providing information and a listening ear, help with financial costs i.e. equipment, hospital travel

Type III

This is a severe form of the condition. Fractures may occur in the womb and the baby is often born with fractures. The height will be very small, arms and legs will also be bent and short.

A Child with Type III OI

Can experience a high number of fractures

Will normally go to mainstream schooling but commonly will need additional support to help prevent fractures.

Babies require adapted car seats and buggies

Will need specially adapted wheelchairs

Will do all the things a child can do, but might find different ways to do them!

An Adult with Type III OI

Will still have fractures, but they may not have as many as when they where younger

The rib cage may not be properly developed leading to respiratory problems

Ligament problems may be evident. This can cause joint problems such as dislocations

Spinal curvature (where the shape of the spine is not right) must be monitored and can cause a great deal of pain

May experience pain with no obvious cause (ligament and spinal problems can both cause pain)

Bending of long bones may be an issue

There are other types of OI that have been clinically identified. These range from Types V-VIII. However the ones detailed above are the most common.

Type IV

This type falls between I and III in severity. There is huge variation in the number of fractures. Diagnosis is often not made until the person is older as the symptoms are easily missed or misdiagnosed.

A Child with Type IV OI

Ligament problems may be evident. This can cause joint problems such as dislocations

Spinal curvature (where the shape of the spine is not right) must be monitored and can cause a great deal of pain

An Adult with Type IV OI

May experience pain with no obvious cause (ligament and spinal problems can both cause pain)

Bending of long bones may be an issue

There are other types of OI that have been clinically identified. These range from Types V-VIII. However the ones detailed above are the most common.

Treatments

The structure of the bone means cells are continually being replaced. Normally there is a balance between the amount of old bone cells removed and new bone cells being formed. Osteoblasts are responsible for new bone formation whilst osteoclasts, are responsible for removing old bone, a process known as bone resorption.

In individuals with Osteogenesis Imperfecta there is evidence of an imbalance in this process.

The Bisphosphonates work by trying to re-dress this imbalance. There are many different Bisphosphonate drugs that vary in the strength of their effects and way they are given.

Bisphosphonates can be taken in a tablet form which is taken once weekly. The method of taken this is quite specific most manage well with the tablet but it can cause stomach irritation. They are also given as an infusion (into a vein through a drip). A person would be required to attend hospital (normally as a day patient) over three consecutive days every three months. It is most common for adults to receive the tablet and children the infusions but this is in no way the rule.

The majority of studies on Bisphosphonates for people with OI have focused on children on infusion. These studies are showing positive results and there are reports of pain reduction, improved bone quality (bone density) and in some case a reduction in the number of fractures.

Surgery is often required by both adults and children. Surgery may focus on individual fractures, or the decision may also be taken to perform rodding, this involves putting rods into the bones to help strengthen them and protect against fractures.

Pain management in the form of standard pain medication might also be required. There are two issues that needto be addressed, short-term pain management (following a fracture) and long term pain management. Many benefit from being referred to specialist Pain Clinics.

Management of OI

Treatment for OI does not just come in the form of medication. A full overall approach is required, this may include (amongst other things):

Physiotherapy

Physiotherapy can help improve muscle tone and fitness. This is crucial as fractures; surgery etc can lead to periods of inactivity. Building up strength can help with pain management and also may shorten the recovery time after a fracture.

Occupational Therapy

Occupational therapy also plays an important role in terms of the practicalities of day to day living. Good quality properly assessed and fitted equipment can make big differences to individuals. Poor seating posture for example (either at a school desk or in a wheelchair) can lead to back pain, hip pain and potentially fractures in the back.

More information on Osteogenesis Imperfecta is available from our factsheets on this website or for more detailed information you can visit the OI Foundation in the USA www.oif.org