About multiple pterygium syndrome

What is multiple pterygium syndrome?

Multiple pterygium syndrome is a very rare genetic disorder characterized by minor facial anomalies, short stature, vertebral defects, multiple joints in a fixed position (contractures) and webbing (pterygia) of the neck, inside bend of the elbows, back of the knees, armpits and fingers. Multiple pterygium syndrome usually follows autosomal recessive inheritance but can also follow autosomal dominant inheritance.

What are the symptoms for multiple pterygium syndrome?

Rocker-bottom or club feet symptom was found in the multiple pterygium syndrome condition

Multiple pterygium syndrome is a very rare disorder characterized by permanently bent fingers (camptodactyly), short stature, rocker-bottom or club feet, joints that are bent in a fixed position (contractures), union or webbing of the skin between the fingers (syndactyly), and/or webbing of the neck, inside bend of the elbows, back of the knees and armpits. The webbing of skin and contractures of the joints that are found in this disorder may restrict movement.

Characteristic facial features can include a small jaw (micrognathia), a long vertical groove in the middle of the upper lip (philtrum), down-slanting eyes, a vertical fold of skin over the inner corner of the eye (epicanthal folds), drooping eyelids, low-set ears, cleft palate and down-turned corners of the mouth.

Backward and lateral curvature of the spine (kyphoscoliosis) and spinal fusion abnormalities occur often in multiple pterygium syndrome. Other skeletal anomalies include rib fusions, hip dislocation, abnormal ear bones and absent or malformed kneecaps.

Males may have undescended testes and an abnormally small penis. Females may have underdeveloped or missing labia majora.

What are the causes for multiple pterygium syndrome?

Multiple pterygium syndrome usually follows autosomal recessive inheritance but can also follow autosomal dominant inheritance.

Genetic diseases are determined by the combination of genes for a particular trait that are on the chromosomes received from the father and the mother.

Recessive genetic disorders occur when an individual inherits the same abnormal gene for the same trait from each parent. If an individual receives one normal gene and one gene for the disease, the person will be a carrier for the disease, but usually will not show symptoms. The risk for two carrier parents to both pass the defective gene and, therefore, have an affected child is 25% with each pregnancy. The risk to have a child who is a carrier like the parents is 50% with each pregnancy. The chance for a child to receive normal genes from both parents and be genetically normal for that particular trait is 25%. The risk is the same for males and females.

All individuals carry 4-5 abnormal genes. Parents who are close relatives (consanguineous) have a higher chance than unrelated parents to both carry the same abnormal gene, which increases the risk to have children with a recessive genetic disorder.

Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease. The abnormal gene can be inherited from either parent, or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from affected parent to offspring is 50% for each pregnancy regardless of the sex of the resulting child.

What are the treatments for multiple pterygium syndrome?

Therapy is supportive and depends on the severity of the webbing and spinal abnormalities. Orthopedic specialists should be consulted once a diagnosis is made because scoliosis develops before age five in most patients. Affected individuals have an increased risk for developing pneumonia due to a small rib cage so respiratory infections should be treated promptly. Patients with multiple pterygium syndrome may benefit from plastic surgery in the areas of webbing. This must be done with extreme caution as there may be major nerves and blood vessels in the area that are too short to allow for full extension of the limbs. Plastic surgery may also be performed to improve fused fingers and correct the cleft palate when present. Physical therapy can be of benefit to help in preventing the joints from becoming fixed.

Drooping eyelids can interfere with vision so an ophthalmology specialist should be consulted. Hearing testing should be done because of an increased risk for conductive hearing loss.

Genetic counseling may be of benefit for patients and their families.

What are the risk factors for multiple pterygium syndrome?

Multiple pterygium syndrome is a rare genetic disorder characterized by pterygium of multiple parts of the body, including the neck, fingers, elbow, armpits, thighs, and back of knees. Pterygium refers to the webbing of the skin. The condition is congenital, and progression is prenatal. There are two types of multiple pterygium diseases: Escobar and lethal. Escobar form, also known as Escobar syndrome, is a milder form and presents with muscle weakness. The lethal type, as the name suggests, is so harmful that most cases result in stillbirth. The signs and symptoms are visible in the fetus or neonates.
Risk factors
1. Multiple pterygium syndrome is caused by mutations in the gene CHRNG that cases for the gamma subunit of the fetal acetylcholine receptor. It leads to the absence of the receptor, which is crucial for neuromuscular communication. Normally, the fetal receptor is replaced with the adult type after the neonatal stage.
2. In the Escobar type, some of the gamma subunits are synthesized, whereas the mutations do not allow the synthesis of any gamma subunits in the lethal type. For this reason, the neuromuscular connection is reformed in the Escobar type, whereas it is not possible in the lethal type.
3. The mutation is inherited in an autosomal recessive manner. Thus, homozygous individuals do not show any signs and symptoms of the disease. They remain asymptomatic carriers. When both mother and father are carriers, there is a chance of 25% for a child to be affected.
4. Familial history of stillbirths with pterygium should prompt risk assessment.

Symptoms
Permanently bent fingers (camptodactyly),Short stature, rocker-bottom or club feet,Joints that are bent in a fixed position (contractures),Union or webbing of the skin between the fingers (syndactyly), and/or webbing of the neck, inside bend of the elbows, back of the knees and armpits,A small jaw (micrognathia),A long vertical groove in the middle of the upper lip (philtrum),Down-slanting eyes,A vertical fold of skin over the inner corner of the eye (epicanthal folds),Drooping eyelids,Low-set ears,Cleft palate and down-turned corners of the mouth,Backward and lateral curvature of the spine (kyphoscoliosis) and spinal fusion abnormalities occur often in multiple pterygium syndrome,Rib fusions,Hip dislocation,Abnormal ear bones and absent or malformed kneecaps,Males may have undescended testes and an abnormally small penis,Females may have underdeveloped or missing labia majora
Conditions
Minor facial anomalies,Short stature,Vertebral defects,Multiple joints in a fixed position (contractures) and webbing (pterygia) of the neck, inside bend of the elbows, back of the knees, armpits and fingers
Drugs
Therapies

Is there a cure/medications for multiple pterygium syndrome?

Multiple pterygium syndrome is a disorder that roots in error in neuromuscular communication. It is of two forms: Escobar and lethal. Mutations in the gene CHRNG that codes for the gamma subunit of the fetal acetylcholine receptor. In a normal fetus, this subunit is replaced with an adult form after birth. In patients with Escobar type, some of the gamma subunits are expressed that allow the replacement after birth. But in the lethal type, there is the absolute absence of expression, so there is no room for later replacement. Hence, the lethal form is characterized by muscle weakness, which is not present in the Escobar type.
Treatment
1. Presently, there is no complete cure for the syndrome. However, supportive and symptomatic therapies are available.
2. The selection of treatment depends on the severity of the webbing and spinal abnormalities.
3. Scoliosis, abnormal lateral curvature of the spine, develops before age five in most patients and needs the attention of orthopedic specialists.
4. Pneumonia, prevalent due to small ribcage, requires prompt treatment with a suitable antibiotic regime. Antibiotic sensitivity tests are preferable for the effective selection of antibiotics.
5. Pterygium patches may require plastic surgery.
6. Fused fingers and cleft palate, if present, also benefit from plastic surgery.
7. Physical therapy, with emphasis on stretching exercises, helps to reduce joint stiffness and contractures.
8. Impaired vision due to drooping eyelids requires an ophthalmologist's attention.
9. Hearing loss may require consultation with an ENT specialist.

Symptoms
Permanently bent fingers (camptodactyly),Short stature, rocker-bottom or club feet,Joints that are bent in a fixed position (contractures),Union or webbing of the skin between the fingers (syndactyly), and/or webbing of the neck, inside bend of the elbows, back of the knees and armpits,A small jaw (micrognathia),A long vertical groove in the middle of the upper lip (philtrum),Down-slanting eyes,A vertical fold of skin over the inner corner of the eye (epicanthal folds),Drooping eyelids,Low-set ears,Cleft palate and down-turned corners of the mouth,Backward and lateral curvature of the spine (kyphoscoliosis) and spinal fusion abnormalities occur often in multiple pterygium syndrome,Rib fusions,Hip dislocation,Abnormal ear bones and absent or malformed kneecaps,Males may have undescended testes and an abnormally small penis,Females may have underdeveloped or missing labia majora
Conditions
Minor facial anomalies,Short stature,Vertebral defects,Multiple joints in a fixed position (contractures) and webbing (pterygia) of the neck, inside bend of the elbows, back of the knees, armpits and fingers
Drugs
Therapies

Video related to multiple pterygium syndrome