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

• MCDS (Metaphyseal Chondrodysplasia, Schmid type)

What is Metaphyseal Chondrodysplasia, Schmid type? (Definition/Background Information)

• Metaphyseal Chondrodysplasia, Schmid type (MCDS) is a type of skeletal disorder in which there is abnormal bone formation at the end of the long bones (metaphyses)
• Symptoms include short stature with abnormally short arms and legs (short-limbed dwarfism) and bowed legs (genu varum). Additional signs and symptoms may include lumbar lordosis, leg pain, joint pain, hip deformities, and an outward flaring of the bones of the lower rib cage
• As a result of the hip and leg findings, individuals with this condition may have an unusual walk that resembles a waddle
• Metaphyseal Chondrodysplasia, Schmid type is caused by a mutation in one of the collagen genes known as COL10A1
• The mutation may be inherited from a parent or may happen for the first time in an affected individual. The MCDS mutation is passed on in an autosomal dominant manner
• The treatment of Metaphyseal Chondrodysplasia, Schmid type may include physical therapy and/or orthopedic surgery and often requires a team of specialists. Early intervention is important to help children with MCDS reach their potential

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

Who gets Metaphyseal Chondrodysplasia, Schmid type? (Age and Sex Distribution)

• Metaphyseal Chondrodysplasia, Schmid type, is a rare skeletal disorder that may be inherited or sporadic
• The presentation of symptoms may begin in infancy or later in childhood
• Both males and females may be affected

What are the Risk Factors for Metaphyseal Chondrodysplasia, Schmid type? (Predisposing Factors)

• A positive family history may be an important risk factor, since Metaphyseal Chondrodysplasia, Schmid type can be inherited condition
• Currently, no other risk factors have been clearly identified for this disorder

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 Metaphyseal Chondrodysplasia, Schmid type? (Etiology)

• Metaphyseal Chondrodysplasia, Schmid type, is caused by mutation(s) in the COL10A1 gene. This gene codes for the collagen alpha-1(X) chain
• The condition may occur sporadically in individuals with no family history of the disorder, or may be inherited in an autosomal dominant manner

Autosomal dominant inheritance: 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 Metaphyseal Chondrodysplasia, Schmid type?

The signs and symptoms of Metaphyseal Chondrodysplasia, Schmid type, may include:

• Broad middle phalanx of finger
• Distal tibial bowing
• Enlargement of the proximal femoral epiphysis
• Femoral bowing
• Metaphyseal chondrodysplasia
• Metaphyseal cupping of metacarpals
• Metaphyseal cupping of proximal phalanges 
• Mild short stature 
• Proximal femoral metaphyseal abnormality
• Short distal phalanx of finger
• Short middle phalanx of finger
• Waddling gait

Based on the frequency of symptoms observed, the following information may be noted:

Very frequently present symptoms in 80-99% of the cases:

• Abnormality of the metaphysis
• Coxa vara 
• Genu varum 
• Limb undergrowth
• Moderately short stature

Frequently present symptoms in 30-79% of the cases:

• Abnormality of bone mineral density
• Brachydactyly
• Craniosynostosis
• Diaphyseal thickening 
• Frontal bossing
• Hearing impairment
• Hypercalcemia
• Micrognathia

Occasionally present symptoms in 5-29% of the cases:

• Abnormality of epiphysis morphology
• Irregular acetabular roof 
• Irregular vertebral endplates
• Platyspondyly

(Source: Metaphyseal Chondrodysplasia, Schmid type; Orphanet, National Institute of Health and Medical Research (INSERM), Paris.)

How is Metaphyseal Chondrodysplasia, Schmid type Diagnosed?

Metaphyseal Chondrodysplasia, Schmid type 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 Metaphyseal Chondrodysplasia, Schmid type?

The complications of Metaphyseal Chondrodysplasia, Schmid type may include:

• Abnormal gait
• Severe pain in legs and joints
• Low self-esteem

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

How is Metaphyseal Chondrodysplasia, Schmid type Treated?

There is no cure for Metaphyseal Chondrodysplasia, Schmid type, since it is a genetic condition.

• The treatment is usually given to manage the signs and symptoms and any complications that develop
• Surgical correction of bone abnormalities may be helpful

How can Metaphyseal Chondrodysplasia, Schmid type be Prevented?

Currently, Metaphyseal Chondrodysplasia, Schmid type may not be preventable, since it is a genetic disorder.

• Genetic testing of the expecting parents (and related family members) may help in understanding the risks better during pregnancy. However, some researchers suggest that prenatal diagnosis should not be recommended
• 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 Metaphyseal Chondrodysplasia, Schmid type? (Outcomes/Resolutions)

• The prognosis of Metaphyseal Chondrodysplasia, Schmid type 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 Metaphyseal Chondrodysplasia, Schmid type:

• Metaphyseal Chondrodysplasia, Schmid type is often mistaken for vitamin D-deficient rickets

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

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