What are the other Names for this Condition? (Also known as/Synonyms)
- Autosomal Dominant Craniometaphyseal Dysplasia
- Autosomal Recessive Craniometaphyseal Dysplasia
- CMDJ (Craniometaphyseal Dysplasia, Jackson Type)
What is Craniometaphyseal Dysplasia? (Definition/Background Information)
- Craniometaphyseal Dysplasia (CMD) is a very rare genetic disorder observed in infants, right from birth. The symptoms of CMD are mainly related to physical abnormalities, especially in the head
- The main risk factor is having a family history of Craniometaphyseal Dysplasia. The disorder is known to be inherited in an autosomal dominant as well as an autosomal recessive manner
- Craniometaphyseal Dysplasia is diagnosed via a physical examination, family history evaluation, and genetic testing
- Surgery for the physical abnormalities and supportive care are the main treatment options for Craniometaphyseal Dysplasia. The prognosis is dependent upon the severity of the symptoms. But, with early and adequate treatment, the prognosis for a majority of individuals is good
Who gets Craniometaphyseal Dysplasia? (Age and Sex Distribution)
- Craniometaphyseal Dysplasia is an extremely rare genetic disorder that is seen in newborn babies (congenital presentation)
- Both males and females can develop the condition
- No specific racial or ethnic group bias is noted with the condition
What are the Risk Factors for Craniometaphyseal Dysplasia? (Predisposing Factors)
- The biggest risk factor of developing Craniometaphyseal Dysplasia is a family history of the condition
- The disorder may be inherited in an autosomal dominant or autosomal recessive (in rare cases) manner, which means that either both parents or only parent can transfer the abnormal gene to their offspring causing CMD
- Parents, who are close blood relatives, have a greater chance of carrying the abnormal genes that may be passed on to their children
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 Craniometaphyseal Dysplasia? (Etiology)
Craniometaphyseal Dysplasia is a congenital condition that may be inherited in an autosomal dominant or autosomal recessive manner.
- The disorder may develop due to mutation in the short arm of chromosome 5, for Autosomal Dominant Craniometaphyseal Dysplasia
- The disorder may also develop due to mutation in the long arm of chromosome 6, for Autosomal Recessive Craniometaphyseal Dysplasia; however, this is more rare
- Sporadic (random) mutations during early embryological development: In such individuals, neither of the parents may show signs and symptoms of the disorder or be carriers of the disorder
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 functioning 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.
Autosomal recessive: Autosomal recessive conditions are traits or disorders that occur when two copies of an abnormal gene have been inherited on a non-sex chromosome. If both parents have an autosomal recessive condition, there is a 100% likelihood of passing on the mutated genes to their children. If, however, only one mutant copy of the gene is inherited, the individual will be a carrier of the condition, but will not be present with any symptoms. Children, born to two carriers, have a 25% chance of being homozygous dominant (unaffected), a 50% chance of being heterozygous (carrier), and a 25% chance of being homozygous recessive (affected).
What are the Signs and Symptoms of Craniometaphyseal Dysplasia?
The signs and symptoms of Craniometaphyseal Dysplasia are usually seen at birth. It may include:
- Abnormal growth or hardening of bones in the forehead or back of the head
- Thicken facial bones
- Thickened bridge at the nose and jaw
- Hardening of bones in the limbs
- Broadening shaft of long bones in the center
- Narrow nasal passages
- Inflammation of the mucus membranes
- Widely-spaced and bulging eyes
- Facial paralysis, deafness, and loss of vision from pressure in the head compressing the brain and nerves
- Nevertheless, normal intelligence is usually seen
How is Craniometaphyseal Dysplasia Diagnosed?
The diagnosis of Craniometaphyseal Dysplasia may involve:
- Compete physical examination upon birth
- A complete family medical history is also evaluated
- X-ray of the affected regions
- Craniometaphyseal Dysplasia is also diagnosed with genetic testing, to look for mutations in the target chromosomes via blood testing
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 Craniometaphyseal Dysplasia?
The complications of Craniometaphyseal Dysplasia may include:
- If the pressure in the brain is not properly managed, the disorder can lead to several other conditions including blindness, deafness, etc.
- Complications that may occur during surgeries to rectify the physical defects
How is Craniometaphyseal Dysplasia Treated?
- Presently, there is no cure for Craniometaphyseal Dysplasia. The main treatment for the condition involves managing the signs and symptoms
- Surgeries may be performed to decrease cranial pressure and fix facial abnormalities. This can help decrease the chance of developing vision or hearing defects
How can Craniometaphyseal Dysplasia be Prevented?
- Currently, there are no specific methods or guidelines to prevent Craniometaphyseal Dysplasia, since it is a genetic condition
- 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 such as Craniometaphyseal Dysplasia
What is the Prognosis of Craniometaphyseal Dysplasia? (Outcomes/Resolutions)
- The prognosis of Craniometaphyseal Dysplasia is generally good with suitable treatment and supportive care. However, the prognosis also depends upon the severity of the signs and symptoms
- The affected individuals can live a normal life as long as the main symptoms, such as facial abnormalities and pressure in the head, are treated early and effectively
Additional and Relevant Useful Information for Craniometaphyseal Dysplasia:
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