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.
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.
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
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