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

• Christian Syndrome
• Skeletal Dysplasia-Intellectual Disability Syndrome
• X-Linked Skeletal Dysplasia-Intellectual Disability Syndrome

What is Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome? (Definition/Background Information)

• Mental Retardation Skeletal Dysplasia Abducens Palsy Syndrome, or Skeletal Dysplasia-Intellectual Disability Syndrome, or, X-Linked Skeletal Dysplasia-Intellectual Disability Syndrome, combines skeletal anomalies (short stature, ridging of the metopic suture, fusion of cervical vertebrae, thoracic hemivertebrae, scoliosis, sacral hypoplasia and short middle phalanges) and mild intellectual deficit
• It has been described in four male cousins in three sibships. Glucose intolerance was present in three cases, and imperforated anus in one case
• Carrier females had minor manifestations (fusion of cervical vertebrae and glucose intolerance). Transmission seems to be X-linked

(Source: X-linked skeletal dysplasia-intellectual disability syndrome; Orphanet, National Institute of Health and Medical Research (INSERM), Paris.)

Who gets Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome? (Age and Sex Distribution)

• Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome is an extremely rare congenital disorder, described in less than 10 individuals in the medical literature 
• The presentation of symptoms may occur at birth. Based on available information, the condition appears to predominantly affect males
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome? (Predisposing Factors)

• A positive family history may be an important risk factor, since Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome can be inherited
• Currently, no other risk factors have been clearly identified for this syndrome

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 Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome? (Etiology)

• The gene mutation that causes Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome is not known at the present time
• The condition appears to be inherited in an X-linked manner

X-linked recessive pattern: The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

What are the Signs and Symptoms of Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome?

The signs and symptoms of Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome may include:

• Abducens palsy
• Cranial nerve VI palsy
• Glucose intolerance
• Prominent metopic ridge
• Skeletal dysplasia
• Wide nasal bridge

Based on the distribution pattern of the signs and symptoms, the following may be noted:

• Very frequently present symptoms in 80-99% of the cases:
  • Abnormality of the sacrum
  • Brachydactyly
  • Fused cervical vertebrae
  • Scoliosis
  • Short middle phalanx of finger
  • Short stature
  • Thoracic hemivertebrae
• Frequently present symptoms in 30-79% of the cases: Type II diabetes mellitus
• Occasionally present symptoms in 5-29% of the cases: Anal atresia

(Source: Mental Retardation Skeletal Dysplasia Abducens Palsy; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How is Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome Diagnosed?

Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome 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 Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome?

The complications of Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome may include:

• Difficulty in passing stools
• Low self-esteem
• Reduced quality of life

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

How is Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome Treated?

There is no cure for Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome, since it is a genetic condition. The treatment is usually given to manage the signs and symptoms and any complication that develops.

How can Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome be Prevented?

Currently, Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome may not be preventable, since it is a genetic disorder.

• 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 Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome? (Outcomes/Resolutions)

• The prognosis of Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome 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 Mental Retardation-Skeletal Dysplasia-Abducens Palsy Syndrome:

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

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