Age of onset: at birth.

• GJH depends on an individual's age, sex, and family and ethnic background. Joint hypermobility in cEDS is usually general, affecting both large and small joints, and is usually noted when a child starts to walk. It should be assessed using the Beighton scale, the most widely accepted grading system for the objective semiquantification of joint hypermobility . A Beighton score of ≥5 is considered positive for the presence of GJH.Table 1. Beighton Criteria for Joint HypermobilityJoint/Finding. Negative. Unilateral. Bilateral. Passive dorsiflexion of the 5th finger 90. 0. 1. 2. Passive flexion of thumbs to the forearm. 0. 1. 2. Hyperextension of the elbows beyond 10. 0. 1. 2. Hyperextension of the knees beyond 10. 0. 1. 2. Forward flexion of the trunk with knees fully extended and palms resting on the floor. 0. 1 Since laxity decreases with age, individuals with a Beighton score of 5 may be considered positive based on historical observations.. —

Source: GeneReviews — "Classic Ehlers-Danlos Syndrome"

Genetic testing for COL1A1 is available. Testing is considered confirmatory for diagnosis.

Source: GeneReviews — "Classic Ehlers-Danlos Syndrome"

| Assessment for joint instability, occupational physical therapy needs, mobility issues, pain

Neurologic

| Eval for hypotonia motor development | At each visit in infants children

Hematologic

| Assessment for easy bruising /or prolonged bleeding | At each visit

Eval of clotting factors (platelet count, aPTT, PT, thrombin time) | If severe easy bruising is present

Cardiovascular

| Echocardiogram | In those w/normal initial echocardiogram:

• Children: frequency of follow up per pediatric cardiologist

• Adults: no follow-up echocardiogram necessary

In those w/abnormal echocardiogram (aortic dilatation, mitral valve prolapse): annually

aPTT = activated partial thromboplastin time; PT = prothrombin time

Source: GeneReviews — "Classic Ehlers-Danlos Syndrome"

Phenotype severity distribution: 11 always present features.