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

• Axial Osteosclerosis

What is Osteomesopyknosis? (Definition/Background Information)

• Osteomesopyknosis is a bone disorder characterized by abnormal hardening of bone (osteosclerosis). It is generally limited to the axial spine, pelvis, and proximal part of the long bones, which is what distinguishes this condition from other sclerosing bone disorders
• It is usually diagnosed incidentally in young adults complaining of back pain
• Osteomesopyknosis is inherited in an autosomal dominant manner, but the genetic cause has not yet been identified
• It is generally benign and life expectancy is normal

(Source: Osteomesopyknosis; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Who gets Osteomesopyknosis? (Age and Sex Distribution)

• Osteomesopyknosis is a rare congenital disorder. However, the presentation of symptoms is seen between teenage to young adulthood stage
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

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

• A positive family history may be an important risk factor, since Osteomesopyknosis can be inherited
• Currently, no other risk factors have been clearly identified for Osteomesopyknosis

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s 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 Osteomesopyknosis? (Etiology)

Osteomesopyknosis is inherited in an autosomal dominant manner, but the genetic cause has not yet been identified.

• This means that having only one mutated copy of the responsible gene (which has not yet been identified) is enough to cause signs or symptoms of the disorder. When a person with an autosomal dominant condition has children, each child has a 50% (1 in 2) risk to be affected
• There have been reported cases where both parents of an affected person did not appear to have the condition
• The chance of having signs and symptoms when the responsible mutation is present (penetrance), and potential nature of signs and symptoms (expressivity), is not clear

(Source: Osteomesopyknosis; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Autosomal dominant: Autosomal dominant conditions are traits or disorders that are present when only one copy of the mutation is inherited on a non-sex chromosome. In these types of conditions, the individual has one normal copy and one mutant copy of the gene. The abnormal gene dominates, masking the effects of the correctly function gene. If an individual has an autosomal dominant condition, the chance of passing the abnormal gene on to their offspring is 50%. Children, who do not inherit the abnormal gene, will not develop the condition or pass it on to their offspring.

What are the Signs and Symptoms of Osteomesopyknosis?

The signs and symptoms of Osteomesopyknosis may include:

• Infertility
• Low back pain

Osteomesopyknosis may cause chronic, low-grade back pain in the thoracic (middle) and lumbar (lower) regions. It is considered a mild form of osteosclerosis and is usually found in young adults or teenagers. Height and intellect are not affected.

There are cases of association with other findings such as ovarian sclerosis and lymphoma; however, it is uncertain whether they have been coincidental or features of the disorder.

• Very frequently present symptoms in 80-99% of the cases: Increased bone mineral density
  • Abnormal form of the vertebral bodies
  • Kyphosis
  • Scoliosis
  • Vertebral body sclerosis
• Occasionally present symptoms in 5-29% of the cases:
  • Abnormal cortical bone morphology
  • Abnormality of metabolism/homeostasis

(Source: Osteomesopyknosis; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How is Osteomesopyknosis Diagnosed?

Osteomesopyknosis is diagnosed on the basis of the following information:

• Complete physical examination
• Thorough medical history evaluation
• Assessment of signs and symptoms
• Laboratory tests
• Imaging studies
• Biopsy studies, if necessary

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 Osteomesopyknosis?

The complications of Osteomesopyknosis may include:

• Chronic pain
• Spinal curvature (making it difficult to walk)
• Difficulty in performing certain simple/routine tasks
• Infertility, in some cases

Complications may occur with or without treatment, and in some cases, due to treatment also.

How is Osteomesopyknosis Treated?

There is no cure for Osteomesopyknosis, since it is a genetic condition. The treatment is usually given to manage the signs and symptoms and any complications that develop.

How can Osteomesopyknosis be Prevented?

Currently, Osteomesopyknosis may not be preventable, since it is a genetic disorder.

• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders

Regular medical screening at periodic intervals with tests and physical examinations are recommended.

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

• The prognosis of Osteomesopyknosis is dependent upon the severity of the signs and symptoms and associated complications, if any
• Individuals with mild conditions have better prognosis than those with severe symptoms and complications
• Typically, the prognosis may be assessed on a case-by-case basis

Additional and Relevant Useful Information for Osteomesopyknosis:

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

http://www.dovemed.com/diseases-conditions/rare-disorders/