- What is brittle bone disease?
- What are the types of brittle bone disease?
- What causes it?
- How common is the disease?
- What are the symptoms of brittle bone disease?
- How is it diagnosed?
- How is brittle bone disease treated?
- What are its complications?
- Are there ways to prevent brittle bone disease?
- Managing brittle bone disease
The bones are the most important part of our body structure. They are what give us that human form by supporting the body and they need to be strong.
But sometimes, certain ailments can weaken the bones. Brittle bone disease (osteogenesis imperfecta) is one such condition that makes the bones fragile and prone to breakage even from minor impact. The disease can limit a child’s ability to have normal growth and childhood. Though there is no cure for it, the condition is manageable.
What Is Brittle Bone Disease?
Brittle bone disease is medically called osteogenesis imperfecta or simply OI (1) and causes the bones that are otherwise healthy to break easily even from minor impact. Brittle bones are so delicate that they may break suddenly, sometimes without any cause.
Osteogenesis imperfecta is divided into eight types depending on the severity of the bone’s fragility and the gene that causes the disease (2).
What Are The Types Of Brittle Bone Disease?
Brittle bone disease is of eight types, each with a different set of signs and symptoms (3):
- Type 1: It is the most common yet the mildest form of brittle bone disease. It occurs in 1 in 30,000 birth. Nearly 50% of children have type 1 osteogenesis imperfecta, which results in the least number of bone deformities when compared to other types. Type 1 usually occurs due to the direct transfer of faulty genes from the parents to the baby.
- Type 2: It is the most severe form of the disease that is most likely to affect newborns. It is not so common occurring in 1 in 60,000 births. It results in extreme bone deformities and develops due to the transfer of a new gene mutation from the parent.
- Type 3: The first fractures in type 3 brittle bone disease occur immediately after birth. Some infants may already have broken bones at birth, as they suffer fractures as a fetus. This type is often an isolated incident in the family, quite likely due to a spontaneous genetic mutation. It means the baby will be the first one to have the disease, with no history of the condition in the family.
- Type 4: The fragility of the bone lies between that of type one and type two. Type 4 runs in the family and is traceable to a faulty gene in the family tree.
- Type 5: It is very similar to type four in terms of severity. The frequency of fractures and the extent of bone deformity is also the same as that of type four.
- Type 6: This type of brittle bone disease is extremely rare, and it accounts for only 5% of total cases. The severity of symptoms is moderate.
- Type 7: It is similar to the type two or four OI. Research has noted that this type of osteogenesis imperfecta is restricted to a small population of native Canadians.
- Type 8: It is similar to type two or three. The symptoms can be very severe and may be fatal too.
The classification of the brittle bone disease depends on the causative gene. Some additional genes can cause osteogenesis imperfecta different from these eight types (4). Therefore, medical professionals may go as far as classifying the disease to a total of 11 forms, although only the first eight are widely referred to.
[ Read: What Causes Bowed Legs In Babies ]
What Causes Brittle Bone Disease?
The fundamental cause of the brittle bone disease is a genetic defect that inhibits the body’s ability to produce the protein called collagen, which gives your bones their strength and rigidity. Since the body does not produce adequate collagen, it cannot make stronger bones that can withstand pressure. The defective genes that cause the defect vary, thus resulting in different types of osteogenesis imperfecta.
The genes responsible for brittle bones can be categorized as dominant and recessive. Dominant genes cause brittle bones even if the baby receives one copy of the gene from one of the parents. Dominant gene cases are likely to run in families since the dominant defective gene from one parent will always override the healthy gene from another parent. Dominant gene defect is responsible for 90% of brittle bone disease cases.
Recessive gene defect is when the baby receives the defective gene from both the parents. The parents will not have the disease and may not be aware that they are carrying the defective gene. Recessive genes usually lead to that isolated cases where only the baby and no one else in the family has the condition. It can occur mainly in marriages between cousins or relatives.
How Common Is Brittle Bone Disease?
According to the US National Library of Medicine, osteogenesis imperfecta affects six to seven individuals per 100,000. Type one and four are the most common since they are responsible for four to five cases per 100,000 individuals (5). About 20,000 to 50,000 people in the US have the brittle bone disease (6).
What Are The Symptoms Of Brittle Bone Disease?
There are certain features common to all types of brittle disease. The main feature is weak bones that can easily break. In severe cases, fractures can occur at birth or the bones can break with the smallest impact. In mild cases fractures occur after a fall or hit. The bone takes a longer time to heal and deformities occur. Sometimes, the child or parents are not aware of the fracture as it heals slowly by itself. The parents become aware only after they notice the deformity and x-rays are done.
The other symptoms of the brittle bone disease vary based on the type it is categorized into and include:
- Normal stature or slightly shorter than the ideal height for the age.
- Frequent fractures, as the bones break easily when subjected to pressure or impact.
- The white of the eye called sclera has a bluish tinge to it. It is due to a deficiency of collagen in the body.
- The teeth that emerge later are also brittle. Babies will eventually face dental problems as they grow older.
- An odd, inverted triangle shape of the face.
- Spinal curvatures are common due to weak bones.
- Hearing loss develops during the early 20s and the 30s.
- Loose joints and low muscle tone.
- Skin bruises easily due to the low levels of collagen.
- A more severe form of the disorder, which leads to fractures and bone deformities.
- The bones break right after birth or even during delivery.
- Arms and legs are abnormally short at birth. Limbs may even be improperly formed.
- Small stature, small chest, and under-developed lungs. The ribs cage is deformed. The lungs cannot expand normally leading to frequent respiratory infections. This anomaly can lead to heart failure.
- Other noticeable body deformities include a narrow nose, a small jaw, and abnormally soft skull, which is called fontanelle. The child also displays symptoms of type one OI such as thin, fragile skin and low muscle tone.
- Symptoms are same as type one symptoms and body deformities similar to that of type two OI including a narrow nose, small jaw, and low muscle tone.
- Fractures will be present at birth. An x-ray will reveal the healing of bones, which indicates fractures sustained inside the uterus.
- Ribs and limb bones could be deformed at birth. Further degeneration is progressive and the child may eventually need a wheelchair for mobility.
- Same symptoms as type one and type three osteogenesis imperfecta. Bones are deformed and the child may experience several fractures usually before puberty.
- The sclera, which is the white of the eye, will be normal or have a very slight tinge of blue that is hard to detect.
- Brittle and discolored teeth.
- Same as that of type four. Parts of the bone that sustained fracture become enlarged through the formation of bone calluses, which are unusually hard parts of the bone formed at the site of the fracture.
- Enlargement of the bone may occur randomly even without any prior fracture.
- The movement of the forearm (arm below the elbow) is restricted. There is also a risk of dislocation of the arm.
- This type is rare and the symptoms are the same as type four, but moderate in severity.
- The symptoms either resemble that of type four or type two. Type seven is less common in the broader population and is limited to a small community of Canadians (7).
- The white of the eye is normal and does not have any bluish tinge.
- The face is round, and the head small.
- Limbs are shortened. A hip deformity is very common in this type of brittle bone disease.
- Symptoms are similar to type two or three with the exception that the sclera is white.
- The bones are extremely weak. The limbs are short, and the fontanelle at the top of the skull is very soft.
- The disease is progressive. The baby eventually suffers from growth deficiency and severe osteoporosis.
Accurate diagnosis of the type and severity of the condition is must to keep the baby safe.
How Is Brittle Bone Disease Diagnosed?
Following are the options used for diagnosing brittle bone disease.
- Prenatal diagnosis: A regular ultrasound scan of the pregnant mother can be used to observe the development of bones in the fetus. If the doctor strongly suspects osteogenesis imperfecta, then they may consider amniocentesis, a test where they take a sample of the amniotic fluid. Doctors test the fluid for the presence of genetic anomalies.
- Symptomatic diagnosis: If the baby develops fractures right after birth or has oddly shaped bones, then the doctor will assess the symptoms carefully to check if it is OI. Certain body defects like triangular face and loose joints point straight towards brittle bone disease. A bluish sclera can also indicate the presence of osteogenesis imperfecta.
- X-ray: X-ray will help determine bone deformities, fractures, and their location. X-rays are extremely important for diagnosis.
- Dual Energy X-ray Absorptiometry scan (DEXA scan): The DEXA scan checks the bone density. It gives an advantage over standard X-ray since it can tell the precise bone density, which can help the doctor determine the severity of the brittle bone disease.
- Skin and bone biopsy: A doctor may collect a sample of the bone or the skin to measure the collagen content. Abnormally low levels of collagen will indicate osteogenesis imperfecta.
- Blood and saliva test: It provides a conclusive test by testing the DNA for the defective genes for the brittle bone disease.
The doctor will discuss the next course of action based on the diagnosis.
[ Read: Signs Of Muscular Dystrophy In Babies ]
How Is Brittle Bone Disease Treated?
There is no treatment or medicine to cure brittle bone disease (8). The treatment procedures aim at easing the symptoms and improving the quality of patient’s life. The ideal option depends on the age of the child, type of osteogenesis imperfecta, the severity of the condition, and overall health of the baby. The following treatment procedures are used for rectifying the problems caused by the brittle bone disease:
- Surgical procedures: A wide variety of surgical procedures can help reduce the susceptibility of bones to break. A common procedure employed is the insertion of a metal rod through the entire length of the bones of arm and legs (femur and humerus). The metal rod provides rigidity to the bone and prevents abnormal bending of the bone that causes deformity.
Doctors often refer to this procedure as rodding. Other methods include bracing, where metal braces stuck to the spine can prevent spinal curvature. Dental implants may be necessary as the baby grows older.
- Physical therapy: Therapy aims at reinforcing the strength and density of the bones and muscle strength and tone through exercises. Once the baby is old enough, doctors may suggest physical therapy through games and activities. You can refer to a certified physical therapist who may consider hydrotherapy including swimming and water exercises, as movement in water poses no risk of fracture.
- Oral medicines: Oral medications for OI usually contain a compound called bisphosphonate that can help improve the strength of the bone. These are usually given to older children. Alternative medications include growth hormones and medicines for gene therapy.
- Assistive devices: The child may need a wheelchair, a support stick, and other customized devices for mobility.
Treatment options may not cure the disease, but play a key role in easing the intensity of the disease, which eventually can help in mitigating complications.
What Are The Complications Of Brittle Bone Disease?
Brittle bone disease has an impact on several other functions of the body. Here are the complications of brittle bone disease:
- Hearing loss
- Problems in bone joints
- Respiratory infections
- Heart problems
- Eye problems including vision loss
Are There Ways To Prevent Brittle Bone Disease?
Preventing osteogenesis imperfecta is unlikely since faulty genes, which cannot be altered, are the cause of it. Parents can take a few steps to minimize the risk of the child developing the condition:
- Learn if you have a family history of the condition: Find out if anyone in your family had or has the disease. It may do little to prevent the condition, but it can give you an idea whether it is recessive or dominant. For instance, if one of your siblings has the condition, but you do not, then you have a 50% chance of being the carrier of the defective recessive gene.
- DNA testing: DNA testing provides you a clearer picture. Several clinics offer DNA testing to detect a set of faulty genes that can lead to birth defects such as brittle bones.
- Be prepared through regular ultrasound scans: Your doctor can identify the condition in the unborn child through analysis of ultrasound scans. If your doctor states that the baby could have osteogenesis imperfecta, then prepare yourself with the necessary knowledge and resources to better handle the baby’s condition.
Learning how to manage the condition is the key to keeping complications at bay and let the baby grow healthy.
[ Read: Importance Of Vitamin D For Babies ]
Managing Brittle Bone Disease
Proper management of the brittle bone disease is the key to long-term relief to the child. Here is what you can do to make life easier for a child with OI:
- Prevent fractures: Babies with OI can develop a fracture even if left in one position for a very long time. Keep changing the baby’s position when they are asleep and be extra careful about how you change their diapers or bathe them. Remember a baby with brittle bones is extra delicate and must be held as gently as possible. Consult the doctor and a therapist on how best to handle the baby safely, during the day-to-day tasks As the child grows older, take all measures to prevent falls.
- Keep infections away: The child may become susceptible to respiratory infections. Protect your child by getting them immunized for all possible infections, including the flu. Keep them away from others with a cold and other respiratory infections. Maintain and teach the child proper hygiene.
- Have a regular exercise routine: A daily routine of exercise and activity will help keep your baby’s bones in good shape while also improving muscle tone. Stick to the schedule stated by the therapist and never miss even a single session of activity.
- Focus on weight management: Therapy and exercise is the best way of preventing weight gain in those with brittle bones. OI limits the ability to move and participate in activities that can help in maintaining ideal body weight. But then, being overweight can put pressure on the bones. Following the exercise and therapy routine is the best way to keep your child in good shape.
- Do not forget the checkups: Regular checkups help detect fractures and deformities early, thus allowing the doctor to intervene and prevent complications.
Brittle bone disease is untreatable and can cause psychological and physical pain. But advancements in technology and the improvements in medicine help lessen the pain and allow people with osteogenesis imperfecta live normal lives. Most individuals with OI can live healthy, satisfying lives. They can attend school, develop friendships, participate in events, and grow up to have jobs. The disease is seldom a limit and parents can lay the foundation for it right at the start the early days of their child.
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2. Osteogenesis Imperfecta in Children; University of Rochester
3. Osteogenesis Imperfecta in Children; Children’s Hospital of Philadelphia
4. R.D. Steiner, J. Adsit, & D. Basel, COL1A1/2-Related Osteogenesis Imperfecta; National Center for Biotechnology Information
5. Osteogenesis imperfecta; U.S. National Library of Medicine
6. Osteogenesis Imperfecta; National Organization for Rare Disorders
7. L.M. Ward et al., Osteogenesis imperfecta type VII, National Center for Biotechnology Information
8. Osteogenesis Imperfecta Overview; U.S. Department of Health and Human Services