COL1A1 and COL1A2 variants in Ehlers-Danlos syndrome phenotypes and COL1-related overlap disorder.

Pathogenic variants in COL1A1 and COL1A2 are involved in osteogenesis imperfecta (OI) and, rarely, Ehlers-Danlos syndrome (EDS) subtypes and OI-EDS overlap syndromes (OIEDS1 and OIEDS2, respectively). Here we describe a cohort of 34 individuals with likely pathogenic and pathogenic variants in COL1A1 and COL1A2, 15 of whom have potential OIEDS1 (n = 5) or OIEDS2 (n = 10). A predominant OI phenotype and COL1A1 frameshift variants are present in 4/5 cases with potential OIEDS1. On the other hand, 9/10 potential OIEDS2 cases have a predominant EDS phenotype, including four with an initial diagnosis of hypermobile EDS (hEDS). An additional case with a predominant EDS phenotype had a COL1A1 arginine-to-cysteine variant that was originally misclassified as a variant of uncertain significance despite this type of variant being associated with classical EDS with vascular fragility. Vascular/arterial fragility was observed in 4/15 individuals (including one individual with an original diagnosis of hEDS), which underscores the unique clinical surveillance and management needs in these patients. In comparison to previously described OIEDS1/2, we observed differentiating features that should be considered to refine currently proposed criteria for genetic testing in OIEDS, which will be beneficial for diagnosis and management. Additionally, these results highlight the importance of gene-specific knowledge for informed variant classification and point to a potential genetic resolution (COL1A2) for some cases of clinically diagnosed hEDS.

Hypermobile Ehlers-Danlos syndrome: A review and a critical appraisal of published genetic research to date.

The Ehlers-Danlos syndromes (EDS) are a collection of rare hereditary connective tissue disorders with heterogeneous phenotypes, usually diagnosed following clinical examination and confirmatory genetic testing. Diagnosis of the commonest subtype, hypermobile Ehlers-Danlos Syndrome (hEDS), relies solely on a clinical diagnosis since its molecular aetiology remains unknown. We performed an up-to-date literature search and selected 11 out of 304 publications according to a set of established criteria. Studies reporting variants affecting collagen proteins were found to be hindered by cohort misclassification and subsequent lack of reproducibility of these genetic findings. The role of the described variants affecting Tenascin-X and LZTS1 is yet to be demonstrated in the majority of hEDS cases, while the functional implication of associated signaling pathways and genes requires further elucidation. The available literature on the genetics of hEDS is scant, dispersed and conflicting due to out-dated nosology terminology. Recent literature has suggested the role of several promising candidate mechanisms which may be linked to the underlying molecular aetiology. Knowledge of the molecular genetic basis of hEDS is expected to increase in the near future through the mainstream use of high-throughput sequencing combined with the updated classification of EDS, and the upcoming Hypermobile Ehlers-Danlos Genetic Evaluation (HEDGE) study.

Exercise and Rehabilitation in People With Ehlers-Danlos Syndrome: A Systematic Review.

Objective: To conduct a systematic review examining the effect of exercise and rehabilitation in people with Ehlers-Danlos syndrome (EDS). Data Sources: The following databases were systematically searched: MEDLINE, MEDLINE In-Process/ePubs, Embase, Cochrane Central Register of Controlled Trials, PsycINFO, and Cumulative Index to Nursing and Allied Health. The final time point captured by the search is November 27, 2020. Study Selection: Eligible study designs included case-control, case-series, prospective cohort, retrospective cohort, and intervention studies of structured exercise or rehabilitation interventions. Eligible populations included adults (18 years or older) with EDS (all subtypes) and hypermobility spectrum disorders. The search was restricted to articles published in English. Data Extraction: Data were extracted by 2 independent reviewers. Risk of bias was assessed using the Physiotherapy Evidence Database (PEDro) scale for randomized controlled trials (RCTs) and Risk Of Bias In Nonrandomized Studies of Interventions (ROBINS-I) for non-RCTs. Reporting quality of RCTs was assessed using the Consolidated Standards for Reporting of Trials statement with the harms extension. Reporting was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Data Synthesis: The search yielded 10 eligible studies including 330 participants. The study designs included 5 RCTs, 1 cohort, 2 single-arm interventions, 1 retrospective, and 1 feasibility study. All studies showed some improvement in a physical and/or psychological outcome after the intervention period. One adverse event (nonserious) potentially related to the intervention was reported. Of the 5 RCTs, 2 were rated as high quality with low risk of bias using PEDro, and the majority of non-RCTs were rated as critical risk of bias by ROBINS-I. Conclusions: The results suggest that exercise and rehabilitation may be beneficial for various physical and psychological outcomes. Adequately powered and rigorous RCTs of exercise and rehabilitation interventions for people with EDS are needed.

A novel COL1A1 variant in a family with clinical features of hypermobile Ehlers-Danlos syndrome that proved to be a COL1-related overlap disorder.

COL1-related overlap disorder is a condition, which is not yet considered as part of the 2017 EDS classification. However, it should be investigated as an alternative diagnosis for any patient with hypermobile EDS. This could allow providing appropriate genetic counseling.