What are the other Names for this Condition? (Also known as/Synonyms)

• Ivory Bones
• Albers-Schonberg Disease
• Osteosclerosis Fragilis Generalisata

What is Osteopetrosis? (Definition/Background Information)

• Osteopetrosis is a genetic bone disease that results in dense bones that are susceptible to breakage.
• In individuals with osteopetrosis, bone mass increases, but the additional mass bone that is added is weak, porous, and brittle. This causes an individual to have big bones that have poor strength and prone to fractures
• Three major types of osteopetrosis have been identified: malignant infantile type of osteopetrosis, intermediate type of osteopetrosis, and adult type of osteopetrosis. Malignant infantile osteopetrosis is present from birth, intermediate develops during adolescence, and the adult form becomes apparent during adulthood.
• There are three different patterns of inheritance of osteopetrosis: autosomal dominant, autosomal recessive, and X-linked.
• The different types of osteopetrosis are differentiated based on different set of signs and symptoms.

Who gets Osteopetrosis? (Age and Sex Distribution)

• Both males and females of all ages are able to get osteopetrosis.
• Individuals are more likely to get the disease if there is a history of osteopetrosis in their family.
• No racial, ethnic or geographical predilection is noted

What are the Risk Factors for Osteopetrosis? (Predisposing Factors)

Common risk factors of osteopetrosis include:

• A family history of osteopetrosis 

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider. 

What are the Causes of Osteopetrosis? (Etiology)

• Osteopetrosis is caused by mutations in at least nine different genes. Researchers have identified the CLCN7 gene, the TCIRG1 gene, and IKBKG gene as the most commonly mutated genes in individuals with osteopetrosis.
• The genes that are associated with osteopetrosis are important in the formation and development of osteoclasts ( a type of bone cell) , which are important in breaking down bone tissue during remodeling.
• When mutations are present, osteoclasts are abnormal or absent from the body. This prevents old bone from being broken down and results in abnormally dense bones. 

What are the Signs and Symptoms of Osteopetrosis?

Common signs and symptoms of osteopetrosis include:

• Breakable bones
• Bruising and Bone pain
• Carpal tunnel syndrome
• Osteoarthritis of various joints
• Paralysis of various nerves due to nerve compression or damage to nerves due adjacent bone fractures
• Loss of muscle control
• Large liver/spleen (hepatomegaly and splenomegaly)
• Low calcium levels in blood (hypocalcemia)
• Low blood count (pancytopenias)

How is Osteopetrosis Diagnosed?

• A complete medical history and through physical examination
• Osteopetrosis is most commonly diagnosed after conducting X-rays. If abnormalities or increases in bone density are found, the disease is is thought to be present.
• To confirm the diagnosis, bone biopsies are done.
• Genetic test to determine the presence of known mutations.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis. 

What are the possible Complications of Osteopetrosis?

• Children with osteopetrosis commonly develop difficulties producing blood cells due to osteopetrosis. This causes in low numbers of white cells ( cells that fight infection), low number red blood cells ( cells that carry oxygen to the tissues) and low platelets( cells that help in controlling bleeding). In many cases, this decreased numbers of cells leads to infection, anemia or severe bleeding.
• Children may also suffer from developmental delays due to increased skull density, or vision and hearing problems.
• Cranial nerve compression often results in adults with osteopetrosis causing a variety of signs and symptoms (cranial nerve palsy) 

How is Osteopetrosis Treated?

There are many treatment modalties for Osteopetrosis. They include:

• Interferon gamma-1b has been approved for use in the United States to treat osteopetrosis.
• Bone marrow transplants are done to treat severe malignant infantile osteopetrosis. There is a high risk of death with this procedure, so it is rarely utilized.
• Many medical professionals suggest high doses of calcitriol to stimulate osteoclasts and alleviate symptoms.
• Many individuals also seek physical and occupational therapy, especially for children with osteopetrosis, in order to aid in normal development. 

How can Osteopetrosis be Prevented?

• Osteopetrosis is a genetically inherited disease, which means that there are no preventative measures that can be taken.
• If you have a family history of the disease, it is important to consult with a genetic counselor before becoming pregnant to understand the risks associated.

What is the Prognosis of Osteopetrosis? (Outcomes/Resolutions)

• Most children with osteopetrosis die before the age of ten unless they receive proper treatment.
• Most adults with the disease have normal life spans with milder symptoms than infants and children.

Additional and Relevant Useful Information for Osteopetrosis:

The following DoveMed website link is a useful resource for additional information:

https://www.dovemed.com/health-topics/orthopedc-disorders/