Disease Profile

Multiple pterygium syndrome Escobar type

Prevalence ?
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.
<1 / 1 000 000

< 331

US Estimated

< 514

Europe Estimated

Age of Onset





Autosomal dominant ?A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease


Autosomal recessive ?Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype


X-linked dominant ?X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


X-linked recessive ?Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder


Mitochondrial or multigenic ?Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor ?Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other Names (AKA)

Escobar syndrome; Multiple pterygium syndrome nonlethal type; Pterygium syndrome;


Congenital and Genetic Diseases


Multiple pterygium syndrome, Escobar type is characterized by webbing of skin (pterygium) and a lack of muscle movement (akinesia) that occur before birth. The pterygium typically affect the neck, fingers, elbows, and/or knees. Individuals with multiple pterygium syndrome, Escobar type may also develop a restriction of the joints, known as arthrogryposis, a sideways curve of the spine (scoliosis), and distinctive facial features. Males with this condition can have undescended testes (cryptorchidism).[1][2] Mutations in the CHRNG gene cause most cases of this disorder. It tends to be inherited in an autosomal recessive fashion.[1][3] While there is still no cure for this disorder, treatment options will depend on the type and severity of symptoms.


Symptoms of multiple pterygium syndrome, Escobar type vary but may include short stature, vertebral (spine) defects, joint contractures, and webbing of the neck, armpit, elbow, knee, between the legs, and of the fingers and toes.[4] The joint contractures may make walking more difficult. Other symptoms may include down-slanting eyes, skins fold over the inner corners of the eyes (epicanthal folds), a small jaw, cleft palate, low set ears, and drooping eyelids (ptosis). Males with Escobar syndrome may have undescended testicles at birth, and females may have absent labia majora.[1][2][4]

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Antecubital pterygium
Axillary pterygium
Finger syndactyly
Limitation of joint mobility
Decreased joint mobility
Decreased mobility of joints
Limited joint mobility
Limited joint motion

[ more ]

Multiple pterygia
Pectus excavatum
Funnel chest
Popliteal pterygium
Symphalangism affecting the phalanges of the hand
Fused finger bones of the hand
Webbed neck
Neck webbing
30%-79% of people have these symptoms
Abnormal foot morphology
Abnormal feet structure
Abnormality of the feet
Abnormality of the foot
Foot deformities
Foot deformity

[ more ]

Aplasia/Hypoplasia of the abdominal wall musculature
Absent/small abdominal wall muscles
Absent/underdeveloped abdominal wall muscles

[ more ]

Aplasia/Hypoplasia of the skin
Absent/small skin
Absent/underdeveloped skin

[ more ]

Arthrogryposis multiplex congenita
Camptodactyly of finger
Permanent flexion of the finger
Downslanted palpebral fissures
Downward slanting of the opening between the eyelids
Eye folds
Prominent eye folds

[ more ]

Facial asymmetry
Asymmetry of face
Crooked face
Unsymmetrical face

[ more ]

High palate
Elevated palate
Increased palatal height

[ more ]

Wide-set eyes
Widely spaced eyes

[ more ]

Decreased activity of gonads
Intrauterine growth retardation
Prenatal growth deficiency
Prenatal growth retardation

[ more ]

Long face
Elongation of face
Increased height of face
Increased length of face
Vertical elongation of face
Vertical enlargement of face
Vertical overgrowth of face

[ more ]

Low-set ears
Low set ears
Lowset ears

[ more ]

Abnormally small skull
Decreased circumference of cranium
Decreased size of skull
Reduced head circumference
Small head circumference

[ more ]

Little lower jaw
Small jaw
Small lower jaw

[ more ]

Neonatal respiratory distress
Infantile respiratory distress
Newborn respiratory distress
Respiratory distress, neonatal

[ more ]

Pointed chin
Pointy chin
Small pointed chin
Witch's chin

[ more ]

Drooping upper eyelid
Short stature
Decreased body height
Small stature

[ more ]

Corners of eye widely separated
Umbilical hernia
Vertebral segmentation defect
5%-29% of people have these symptoms
Abnormal aortic valve morphology
Abnormality of the tongue
Abnormal tongue
Tongue abnormality

[ more ]

Absence of labia majora
Absent vaginal lips
Aortic aneurysm
Bulge in wall of large artery that carries blood away from heart
Cleft palate
Cleft roof of mouth
Cognitive impairment
Abnormality of cognition
Cognitive abnormality
Cognitive defects
Cognitive deficits
Intellectual impairment
Mental impairment

[ more ]

Conductive hearing impairment
Conductive deafness
Conductive hearing loss

[ more ]

Undescended testes
Undescended testis

[ more ]

Long, narrow head
Tall and narrow skull

[ more ]

Failure to thrive
Faltering weight
Weight faltering

[ more ]

Gait disturbance
Abnormal gait
Abnormal walk
Impaired gait

[ more ]

Hypoplasia of penis
Underdeveloped penis
Inguinal hernia
Long philtrum
Low posterior hairline
Low hairline at back of neck
Morphological abnormality of the gastrointestinal tract
Abnormal shape of the digestive system
Pulmonary hypoplasia
Small lung
Underdeveloped lung

[ more ]

Rib fusion
Fused ribs
Scrotal hypoplasia
Smaller than typical growth of scrotum


Most cases of multiple pterygium syndrome, Escobar type are caused by mutations in the CHRNG gene. The CHRNG gene provides instructions for part of the acetylcholine receptor (AChR) protein. The AChR protein is found in skeletal muscle cells and is critical for signaling between nerve and muscle cells. Signaling between these cells is necessary for movement.[2][3]

Mutations in other genes have been identified that cause multiple pterygium syndrome, Escobar type. Some people with this condition do not have an identified mutation in any of the known associated genes associated with this condition. The cause of the condition in these individuals is unknown.[2]


Multiple pterygium syndrome, Escobar type is diagnosed based on signs and symptoms. Symptoms that may raise the suspicion of this diagnosis include: multiple pterygium, joint contractures present from birth, characteristic facial features, and other congenital anomalies such as undescended testicles (cryptorchidism).[5] Genetic testing may be used to confirm the diagnosis.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.
  • Orphanet lists international laboratories offering diagnostic testing for this condition.


There is currently no cure for multiple pterygium syndrome, Escobar type. As a result treatment is aimed at managing the associated symptoms. Orthopedics should be involved for issues arising from scoliosis. Infections should be treated promptly. Contracture releases have been performed with variable outcome. Physical therapy is important to help minimize contractures. When ptosis (droopy eyelids) is present, the individual should be referred to ophthalmology. Individuals should also be referred to audiology due to the risk of conductive hearing loss.[4]

Learn More

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • Genetics Home Reference (GHR) contains information on Multiple pterygium syndrome Escobar type. This website is maintained by the National Library of Medicine.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Multiple pterygium syndrome Escobar type. Click on the link to view a sample search on this topic.


  1. Multiple pterygium syndrome, Escobar variant. Online Mendelian Inheritance in Man. 7/9/2016; https://www.omim.org/entry/265000. Accessed 11/16/2016.
  2. multiple pterygium syndrome. Genetics Home Reference. November 2011; https://ghr.nlm.nih.gov/condition/multiple-pterygium-syndrome. Accessed 11/16/2016.
  3. Morgan NV et al. Mutations in the embryonal subunit of the acetylcholine receptor (CHRNG) cause lethal and Escobar variants of multiple pterygium syndrome. American Journal of Human Genetics. 2006; 79(2):390-395. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1559492/.
  4. Pterygium Syndrome, Multiple. NORD. 2004; https://rarediseases.org/rare-diseases/pterygium-syndrome-multiple/. Accessed 11/16/2016.
  5. Sung, Ki Hyuka; Lee, Sang-Heonb, Kim, Namshinb, Cho, Tae-Joond. Orthopaedic manifestations and treatment outcome of two siblings with Escobar syndrome and homozygous mutations in the CHRNG gene. Journal of Pediatric Orthopaedics B. May 2015; 24(3):262-267. https://www.ncbi.nlm.nih.gov/pubmed/25411939.