StudyRareStudyRare
Presentations

Hypermobile joints

Log in to star
Dysmorphology Presentations/Skeleton

Last updated 2mo ago

Log in to add personal notes on this page.

A patient whose joints move beyond the normal range. On bedside exam this is captured by the Beighton score (0-9): passive dorsiflexion of the fifth finger >90°, passive thumb apposition to the forearm, hyperextension of the elbow >10°, hyperextension of the knee >10°, and palms-flat-on-floor with knees straight. A score above 4-6 (age-adjusted) qualifies as generalized joint hypermobility. Most generalized hypermobility is benign and has no surveillance implications. The clinical job is to find the heritable connective-tissue disorders hiding in that pool, especially the ones with vascular fragility that need cardiovascular surveillance.

Three questions sort the differential:

  1. Is the hypermobility part of a heritable connective tissue disorder, or is it isolated?
  2. Is there vascular fragility? This is the surveillance-defining question. vEDS, Marfan, and Loeys-Dietz all carry life-threatening aortic or arterial risk; they cannot be missed.
  3. Are the skin, eye, and craniofacial features pointing at a specific syndrome? The pattern recognition is most of the answer.

The EDS spectrum

  • Hypermobile EDS (hEDS): the most common heritable disorder of connective tissue. Clinical diagnosis by the 2017 international criteria; no confirmed causative gene. Joint hypermobility, soft skin, chronic pain, autonomic features (POTS), GI dysmotility. No specific surveillance beyond conservative management.
  • Classical EDS (cEDS) (COL5A1, COL5A2): atrophic "cigarette-paper" scars, skin hyperextensibility, joint hypermobility. Less skin/joint than vascular, more than hypermobile.
  • Vascular EDS (vEDS) (COL3A1): the dangerous one. Thin translucent skin with visible veins, characteristic facies (thin nose, thin lips, small chin, large eyes, lobeless ears), arterial and uterine rupture, sigmoid colon perforation. Joint hypermobility may be limited to small joints. Pregnancy is high-risk. Lifelong arterial surveillance.
  • Kyphoscoliotic EDS (PLOD1, FKBP14), arthrochalasia EDS (COL1A1, COL1A2), dermatosparaxis EDS (ADAMTS2): rarer subtypes with distinctive bedside features.

The aortopathies (vascular fragility without classic skin findings)

  • Marfan syndrome (FBN1, AD): diagnosed by the Ghent criteria. The two-system core is aortic root dilation plus ectopia lentis; supportive systemic features include arachnodactyly (positive thumb and wrist signs), pectus excavatum/carinatum, scoliosis, dural ectasia, mitral valve prolapse, tall stature with reduced upper-to-lower segment ratio. Lifetime echocardiographic surveillance.
  • Loeys-Dietz syndrome (TGFBR1, TGFBR2, SMAD3, TGFB2, TGFB3): the wider-arterial-tree cousin of Marfan. Aortic and arterial dilation are not limited to the root; aneurysms can occur anywhere from the head and neck arteries to the iliacs. Hypertelorism, bifid uvula or cleft palate, generalized arterial tortuosity on imaging. More aggressive surveillance and earlier surgery than Marfan.
  • Familial thoracic aortic aneurysm and dissection (FTAAD) (ACTA2, MYH11, PRKG1, MYLK): non-syndromic aortic disease that runs in families without the systemic stigmata of Marfan or LDS. Joint hypermobility is variable. ACTA2 in particular carries early dissection risk and merits the same imaging cadence.

Connective-tissue syndromes with hypermobility plus other tissues

  • Stickler syndrome (COL2A1, COL11A1, COL11A2): hypermobility + cleft palate (often Pierre Robin sequence) + high myopia and retinal detachment + sensorineural hearing loss + early-onset osteoarthritis. The eye risk drives ophthalmology follow-up; retinal detachment risk is high enough to warrant prophylactic counseling.
  • Marshall syndrome (COL11A1): overlaps Stickler with shorter stature and more dysmorphism.
  • Williams syndrome: transient generalized hypermobility in infants and toddlers; supravalvular AS and cocktail-party personality clinch the broader picture.
  • Larsen syndrome (FLNB): striking hypermobility with multiple large-joint dislocations from birth, characteristic flat facies, and cervical spine instability. The cervical kyphosis is the surveillance issue.

The vascular-fragility triad (the must-know surveillance group)

A useful three-way mental model for the cardiovascular geneticist's hot list:

  • vEDS: thin skin + arteries everywhere + uterine rupture risk in pregnancy.
  • Marfan: aortic root dilation + ectopia lentis + skeletal overgrowth.
  • Loeys-Dietz: aneurysms across the whole arterial tree + hypertelorism + bifid uvula + cleft.
  • Hypermobility + atrophic scars + skin hyperextensibility → classical EDS (COL5A1/COL5A2).
  • Hypermobility + thin translucent skin + characteristic facies + family history of sudden death → vEDS. Confirm with COL3A1; this changes management immediately.
  • Hypermobility + tall stature + arachnodactyly + ectopia lentis → Marfan. Echocardiogram on day one.
  • Hypermobility + hypertelorism + bifid uvula → Loeys-Dietz. The bifid uvula is a 2-second exam finding that flips the diagnosis.
  • Hypermobility + cleft palate + high myopia + hearing loss → Stickler. Ophthalmology referral is non-negotiable.
  • Hypermobility + Beighton 9 + chronic pain + no systemic features → hEDS. Clinical diagnosis, no current gene test.
  1. Beighton score and full musculoskeletal exam. Document the score; it matters for criteria-based diagnoses.
  2. Skin exam: atrophic scars, hyperextensibility, translucency, easy bruising.
  3. Facial exam: Marfan habitus, hypertelorism, bifid uvula, micrognathia, low-set lobeless ears.
  4. Eye exam by ophthalmology: ectopia lentis (Marfan), high myopia and vitreous abnormalities (Stickler).
  5. Echocardiogram: if Marfan, LDS, or vEDS is on the differential, this is the first-day test. Aortic root and arch dimensions establish the baseline.
  6. Cross-sectional vascular imaging (CTA or MRA from head to pelvis) if LDS or vEDS suspected; the disease is not limited to the root.
  7. Family history: sudden death, aortic aneurysm or dissection at any age, ectopia lentis, retinal detachment, scoliosis, cleft palate.
  8. Genetic testing: the panel choice is driven by clinical pattern. An EDS panel for classical/vascular suspicion; a thoracic aortic aneurysm panel (which includes FBN1, TGFBR1/2, SMAD3, COL3A1, ACTA2, MYH11) when the picture is "aortopathy of unclear flavor."
  • The bifid uvula is the single highest-yield bedside finding in this differential. It moves a tall hypermobile patient from Marfan to Loeys-Dietz in one look, and the surveillance is more aggressive.
  • A patient with classic Marfan habitus but no ectopia lentis and with a bifid uvula or cleft is much more likely LDS. Test for it.
  • Most hypermobility is benign. The job of the geneticist is not to slap a syndrome on every flexible patient; it is to find the few who need echos and arterial imaging.
  • vEDS does not always have dramatic skin findings. A young adult with a spontaneous arterial dissection and family history is sometimes the presenting case. Test COL3A1 liberally in unexplained arterial events.
  • Pregnancy counseling matters early: vEDS carries a substantial maternal mortality risk from uterine and arterial rupture, and reproductive planning should happen before conception, not at the first prenatal visit. Marfan and LDS also carry pregnancy aortic risk and warrant pre-conception echocardiography.
  • The Beighton score loses sensitivity with age. An adult with a history of "double-jointed as a kid" plus current connective-tissue features deserves the full workup even if the current Beighton is 2.