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Participant 054

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Female, age 15, with features of multiple pterygium syndrome, Escobar type, caused by changes in the TTN gene

Date of Report

Aug 24, 2021


At birth, these patients were found to have cleft palate, which required surgery to repair. Shortly after, they were noticed to have very low muscle tone (hypotonia) in the arms and neck. The younger sister has increased muscle tone in her legs and wears braces at night on both ankles and on her right hamstring. She has also has surgery on her right Achilles to lengthen it and has had a number of rounds of casting on her right ankle.

A skeletal survey was performed on the older sister at 1 year, which showed fusion of the spine. An echocardiogram (ECHO) around this time showed an abnormal mitral valve. X-rays at 8 years showed a 47 degree curvature of the spine. As a result, the patient had to wear a brace for 24 hours a day and recently underwent surgery. Both siblings have sideways curve of the spine (scoliosis) and inward curve of the spine (lordosis), which is causing them difficulty in breathing.

Her sister, age 8, is similarly affected. Multiple pterygium syndrome can cause webbing of the skin, especially around the neck, fingers, elbows, and knees. Other symptoms of this condition include restriction of the joints (arthrogryposis) and a sideways curve of the spine (scoliosis). This syndrome is typically caused by mutations in the CHRNG gene, but testing for mutations in this gene has been negative.

Both sisters also have webbing of the neck and armpits (axillae), bent fingers (camptodactyly), and a small head size (microcephaly). They both have severe restrictive lung disease and the older sister has had severe coughing episodes that last 3 weeks at a time since the age of 9. They both also have small jaws (micrognathia), which is being treated with orthodontic work. The younger sister has milder symptoms in comparison to her older sister. Both girls are developing as expected.

Symptoms / Signs

Shared symptoms:

  • Decreased body weight and muscle mass
  • Underdeveloped muscles (hypoplasia of the musculature)
  • Small head size (microcephaly)
  • Flattened area at the back of the skull (brachycephaly)
  • Long and triangular face with pointed chin
  • Highly arched eyebrow
  • Low-set ears
  • Cleft palate
  • Small jaw (micrognathia)
  • Webbed and wide neck
  • Bent fingers (camptodactyly)
  • Impaired joint movement of the hand (joint contracture of the hand)
  • Underdevelopment of the folds on the palm of the hand (apalasia/hypoplasia of the palmar creases)
  • Narrow and sunken chest (pectus excavatum)
  • Low-set nipples
  • Restrictive lung disease
  • Increased curvature of the spine (scoliosis)
  • Neck and spine fusions (fused cervical vertebrae)
  • Inability to straighten the knee (knee flexion contracture)
  • Smaller or absent labia (labial hypoplasia)
  • Impaired range of movement of the ankle (ankle contracture)

Older sister only:

  • Short stature
  • Blocked airflow during sleep (obstructive sleep apnea)
  • Narrowed valve of the heart (mitral stenosis)
  • Congenital hip dysplasia
  • Club feet
  • Increased tone (hypertonia) in lower limbs

Younger sister only:

  • Skin fold in upper eyelid (epicanthus)
  • Prominent nasal bridge
  • Backward rotation of the ears (posteriorly rotated ears)
  • Underdeveloped thorax (thoracic hypoplasia)
Current Treatments
Prior Treatments
  • Brace, surgery- scoliosis
  • Cleft palate repair- cleft palate
Considered treatments
Previously Considered Diagnoses
  • Chromosomal disorder (karyotype- normal)
  • Congenital muscular dystrophy with rigid spine (SPEN1 sequencing and deletion/duplication testing- negative)
  • DiGeorge syndrome (FISH 22q11.2- normal)
  • Metabolic condition
  • Multiple pterygium syndrome, Escobar type (CHRNG sequencing and deletion/duplication testing – negative)
  • Myopathy/arthrogryposis syndrome
  • Prader Willi syndrome (methylation studies- normal)
Other Photographs
Genetic Variants of Interest

In 2020, clinicians and researchers identified the following genetic changes to be causing the participant’s symptoms:

Inheritance Pattern
Position (hg19)
DNA Change
Protein Change
chr2:g.179490032del & chr2:g.179597966C>T
c.36812del & c.12322G>A
p.Asp12271ValfsTer10 & p.Asp4108Asn

If this participant sounds like you or someone you know, please contact us!


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