background participants

Participant 171

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Male, age 25, with absent shoulder muscles (congenital bilateral absence of deltoid muscles), underdeveloped bicep tendons, developmental delay, joint hyper-mobility, and skeletal abnormalities caused by a change in the CDH2 gene

Date of Report

Aug 13, 2020


The participant was born with absent shoulder muscles (congenital bilateral absence of deltoid muscles), bilaterally underdeveloped bicep tendons, umbilical and inguinal hernias, and undescended testes (bilateral cryptorchidism), some of which were fixed with surgeries. Developmental delay was noted at 6 months old with delayed milestones. He had an IEP in classes for his learning difficulties and he has graduated high school. Some additional symptoms include: recurrent joint dislocations (jaw, metacarpophalangeal joints), facial differences, skeletal abnormalities, joint hypermobility, and hypogonadism.

Symptoms / Signs
  • Absent shoulder muscles (congenital absence of bilateral deltoid muscles)
  • Underdeveloped biceps tendon (hypoplastic bicep tendon)
  • Jaw dislocations (recurrent mandibular subluxations)
  • Undescended testicles (bilateral cryptorchidism)
  • Global developmental delay, infantile onset
  • Learning disability
  • Facial differences (dental crowding, high, narrow palate, midface retrusion)
  • Difficulty swallowing (dysphagia)
  • Gastroesophageal reflux (GERD)
  • Heart abnormalities (pericardial effusion, abnormal EKG)
  • Curvature of the spine (scoliosis)
  • Joints move beyond normal range (joint hypermobility)
  • Inability to straighten left elbow (elbow flexion contracture)
  • Involuntary mirrored hand movements (bimanual synkinesia)
  • Knuckle dislocations (easily subluxated metacarpophalangeal joints)
  • Muscle problems in GI tract (gastrointestinal dysmotility)
  • Tissues protruding through abdomen (umbilical hernia, inguinal hernia)
  • Deep hip sockets
  • Pes planus (flat feet)
  • No pain sensitivity
  • Reduced ability to smell (hyposmia)
  • Sweat gland abnormalities (possible hyperhidrosis)
  • Hormone abnormalities (hypogonadism, elevated circulating follicle stimulating hormone, decreased inhibin B level)
Current Treatments
  • Physical therapy – joint pain
  • Vitamin D – low vitamin D
Prior Treatments
  • Deltoid flap mobilization
  • Orchiopexy – bilateral cryptorchidism
  • Speech and occupational therapy – developmental and learning disability
  • Surgical repair of inguinal & umbilical hernias
Considered treatments
Previously Considered Diagnoses
Other Photographs
Genetic Variants of Interest

Clinicians and researchers have identified the following de novo genetic change to be causing the participant’s symptoms (Accogli et al., 2019).

Inheritance Pattern
Position (hg19)
DNA Change
Protein Change

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


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