What are the other Names for this Condition? (Also known as/Synonyms)
- Escobar Syndrome
- EVMPS (Escobar Variant of Multiple Pterygium Syndrome)
- Lethal Multiple Pterygium Syndrome (LMPS)
What is Multiple Pterygium Syndrome? (Definition/Background Information)
- Multiple Pterygium Syndrome (MPS) is a very rare congenital disorder, which is mainly characterized by the lack of muscle movement and the presence of webbing (pterygia) of skin in the joint region, observed before birth of the baby
- The presence of webbing of skin surrounding the joints, results in poor joint movement and abnormal joint configuration. Due to this, there is difficulty in flexing/extending the joints of the arms and legs
Based upon the severity of signs and symptoms Multiple Pterygium Syndrome is classified into two types:
- Escobar Variant of Multiple Pterygium Syndrome (EVMPS or Escobar type), which usually has milder signs and symptoms.This condition does not worsen after birth, and the affected individuals typically do not have muscle weaknesses, later in life
- The second type with more severe signs and symptoms is called Lethal Multiple Pterygium Syndrome (LMPS);a condition that usually causes still birth, or death of the baby, soon after birth
Who gets Multiple Pterygium Syndrome? (Age and Sex Distribution)
- Multiple Pterygium Syndrome is very rare disorder. The incidence rate, male to female ratio, and racial/ethnic predilection, have not been established, due to the rarity of thisdisorder
- There have been about 50 confirmed cases,currently reported worldwide
What are the Risk Factors for Multiple Pterygium Syndrome? (Predisposing Factors)
Risk factors for Multiple Pterygium Syndrome are not currently well-established.
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 Multiple Pterygium Syndrome? (Etiology)
- Mutations in the CHRNG gene are said to cause the development of Multiple Pterygium Syndrome. Most cases of MPS, are inherited in an autosomal recessive pattern
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).
- A majority of the Escobar type of MPS are due to mutation in the CHRNG gene.A minority of Lethal Multiple Pterygium Syndrome type have CHRNG gene mutations, but the cause in most of the cases, is currently unknown
- Some cases are inherited in an autosomal dominant pattern
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 Multiple Pterygium Syndrome?
The signs and symptoms due to Multiple Pterygium Syndrome (both non-lethal and lethal variants) include:
The signs and symptoms of the baby do not progress (get worse) after birth. The baby gains muscle strength with time, resulting usually in normal muscle tone and strength. Escobar type features the following signs and symptoms:
- Scoliosis of the spine
- Poorly developed lungs
- Droopy eyelids, slanting of the eyes
- Poorly developed jaw
- Low set ears
- Undescended testis
- Restriction of joint movements due to webbing of skin around the neck, fingers, forearms, inner thighs, and at the back of the knees
- Individuals with Escobar type may also have arthrogryposis, which are joint contractures with joint movement restriction
Lethal Multiple Pterygium Syndrome:Generally, most fatalities occur within weeks 13-40 (2nd and 3rd trimester). Most signs and symptoms of Escobar type overlap with those of the Lethal type; additionally, the following are seen:
- Spine, bone-related medical issues, such as bone fractures, spine/bone fusion, dislocations, severe arthrogryposis, scoliosis
- Fluid collection around the neck called cystic hygroma, excess fluid in the developing fetus called hydropsfetalis
- Poorly developed heart called hypoplastic cardiac development
- Poorly developed lungs, kidneys
- Structural abnormalities in the brain; small size of head (microcephalic cranium)
- Diaphragmatic hernia, abnormally twisted stomach
- Cleft lip, cleft palate
How is Multiple Pterygium Syndrome Diagnosed?
A diagnosis of Multiple Pterygium Syndrome would involve:
- Thorough clinical history and complete physical examination
- Genetic test for mutations in the CHRNG gene
- Variety of radiological imaging tests, such as MRI, x-rays, CT scans; depending on the extent of associated congenital abnormalities
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 Multiple Pterygium Syndrome?
Lethal Multiple Pterygium Syndrome usually results in still birth; the fetus does not fully develop in the uterus.
How is Multiple Pterygium Syndrome Treated?
- Treatment of Multiple Pterygium Syndrome depends on the complexity and severity of associated organ defects
- Constant and periodic medical follow-up,with inputs from a multidisciplinary team isneeded, as part of on-going care. Specialists in different areas of healthcare may be involved since different organ systems are involved
How can Multiple Pterygium Syndrome be Prevented?
- Currently there are no specific methods or guidelines to prevent Multiple Pterygium Syndrome 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 counselling 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
What is the Prognosis of Multiple Pterygium Syndrome? (Outcomes/Resolutions)
- The prognosis depends on the severity of Multiple Pterygium Syndrome
- Escobar type has a much better prognosis than the lethal type.This condition does not worsen after birth of the child, and the affected individuals typically do not have muscular weaknesses, later in life
- With Escobar type MPS; the prognosis depends on the complexity of the associated organ defects and severity of the symptoms. More severe and extensive, the associated congenital defect, worse is the prognoses
- Lethal Multiple Pterygium Syndrome usually results in still birth, with the fetus not fully developingin the uterus
Additional and Relevant Useful Information for Multiple Pterygium Syndrome:
Pterygium means "wings" in Greek language. Pterygium is a common disorder affecting the eyes.The thick membrane over the white of the eye appears like a wing, and hence the name.