| Topic | Summary | Key quantitative / defining details | Supporting citations |
|---|---|---|---|
| Preferred name and synonyms | Hypermobile Ehlers-Danlos syndrome is the current preferred term. Common historical synonyms include **EDS hypermobility type**, **type III EDS**, and overlap terminology with **joint hypermobility syndrome (JHS)** in older literature. | Current literature emphasizes the 2017 nosology and warns that older labels can blur cohorts and reduce reproducibility in research. | (pqac-00000000, pqac-00000002, pqac-00000007) |
| Disease boundary: what hEDS is | hEDS is an EDS subtype defined by **generalized joint hypermobility plus systemic/musculoskeletal features and exclusion of alternative diagnoses**. It is not established by a molecular test. | Core phenotype includes GJH, joint instability/subluxation/dislocation, chronic pain, milder skin involvement than some other EDS types, fatigue, autonomic and GI symptoms in many patients. | (pqac-00000000, pqac-00000001, pqac-00000004) |
| Molecular basis and diagnostic mode | The molecular basis of hEDS remains unresolved; therefore diagnosis is **clinical**, not biomarker- or gene-confirmed in routine practice. Genetic testing is mainly used to identify or exclude other heritable connective-tissue disorders rather than to confirm hEDS itself. | Reviews note that gene findings proposed for hEDS have been conflicting or non-reproducible, and hEDS currently lacks a validated monogenic biomarker. | (pqac-00000000, pqac-00000002, pqac-00000003, pqac-00000004) |
| Adult diagnostic framework: Criterion 1 | Criterion 1 requires **generalized joint hypermobility (GJH)**. | Beighton thresholds summarized in recent reviews of the 2017 framework: **≥6** in pre-pubertal children/adolescents, **≥5** from puberty to age 50, **≥4** over age 50. Adult hEDS diagnosis uses the 2017 criteria after biological maturity. | (pqac-00000001, pqac-00000005, pqac-00000016) |
| Adult diagnostic framework: Criterion 2 | Criterion 2 requires **at least two of three feature sets**: Feature A systemic connective-tissue manifestations, Feature B positive family history, and Feature C musculoskeletal complications. | This structure is repeatedly summarized in later reviews of the 2017 criteria. | (pqac-00000001, pqac-00000002, pqac-00000005) |
| Criterion 2, Feature A examples | Feature A captures systemic signs compatible with a heritable connective-tissue disorder. | Examples listed in recent summaries include **unusually soft/velvety skin, mild skin hyperextensibility, unexplained striae, recurrent abdominal hernias, atrophic scarring, dental crowding, pelvic organ prolapse, marfanoid habitus, mitral valve prolapse, and aortic root dilatation**. | (pqac-00000001, pqac-00000005) |
| Criterion 2, Feature B | Feature B is **positive family history**. | Usually defined as a first-degree relative independently meeting current hEDS criteria. | (pqac-00000001, pqac-00000002) |
| Criterion 2, Feature C examples | Feature C captures musculoskeletal complications typical of symptomatic hypermobility disorders. | Examples include **musculoskeletal pain in ≥2 limbs recurring daily for ≥3 months, chronic widespread/generalized pain for ≥3 months, recurrent atraumatic dislocations, or frank joint instability**. | (pqac-00000001, pqac-00000002, pqac-00000005) |
| Adult diagnostic framework: Criterion 3 | Criterion 3 requires **exclusion of alternative diagnoses** and attention to findings inconsistent with hEDS. | Key exclusions repeatedly noted include **unusual skin fragility** and exclusion of **other heritable/acquired connective-tissue disorders**, including autoimmune rheumatologic disease when relevant. | (pqac-00000001, pqac-00000003, pqac-00000016) |
| hEDS vs HSD | Since 2017, patients with symptomatic hypermobility who do **not** fulfill full hEDS criteria are generally classified under **hypermobility spectrum disorders (HSD)** rather than hEDS. | hEDS and HSD have substantial symptom overlap; in a Mayo cohort of 2088 clinic patients, **66.5%** were diagnosed with HSD and **20.3%** with hEDS using 2017 criteria. | (pqac-00000004, pqac-00000006) |
| hEDS vs HSD: symptom overlap | Both hEDS and HSD can present with high burdens of pain, subluxations, headaches, GI symptoms, mood symptoms, and autonomic complaints. | In the 2024 Mayo cohort, common self-reported prevalences included joint pain **82.0% hEDS vs 88.9% HSD**, subluxations **71.2% vs 72.6%**, headache **68.1% vs 69.1%**, anxiety **60.3% vs 69.3%**, depression **52.2% vs 58.0%**, nausea **54.6% vs 59.5%**, constipation **53.0% vs 57.2%**. | (pqac-00000004) |
| hEDS vs HSD: possible distinctions | Available data suggest differences in distribution of manifestations, but boundaries remain imperfect and evidence is still evolving. | hEDS patients may report more features suggestive of collagen/connective-tissue fragility such as **dislocation, hernias, rectal prolapse**, while some HSD cohorts report more joint/muscle, GI, sleep, allergy, neurologic, and psychological symptom burden. | (pqac-00000004, pqac-00000006) |
| hEDS/HSD vs nonsyndromic generalized joint hypermobility | **Nonsyndromic generalized joint hypermobility (GJH)** refers to joint laxity without the additional systemic or persistent symptomatic pattern needed for hEDS/HSD. | Conceptually, the spectrum runs from asymptomatic GJH → symptomatic hypermobility/HSD → hEDS when full criteria are met. | (pqac-00000007, pqac-00000016) |
| Diagnostic limitations / circularity | hEDS diagnosis remains challenging because the criteria are symptom-based, many manifestations are nonspecific, and features used to define the condition overlap with outcomes later studied as “comorbidities.” | Recent registry work found alternative or additional diagnoses in **26.4%** of patients who met 2017 hEDS criteria in one specialty cohort, underscoring the need for careful exclusionary evaluation. | (pqac-00000003, pqac-00000004, pqac-00000006) |


*Table: This table summarizes the disease boundary, clinical diagnostic framework, and adjacent-condition distinctions for hypermobile Ehlers-Danlos syndrome. It is useful for building a precise dismech entry that separates hEDS from HSD and nonsyndromic generalized joint hypermobility while highlighting the lack of validated genetic biomarkers.*