Walaa Ouf1,2, Aneesh Mazumder1,3
Affiliations
- Health Disparities Think Tank, Cambridge, MA, USA
- Massachusetts Lowell University, Lowell, MA, USA
- Harvard University, Cambridge, MA
INTRODUCTION
Diagnosis is defined as identifying a disease from signs and symptoms utilizing blood tests, imaging, or tissue biopsy (The National Cancer Institute). As the diagnosis process imposes challenges and difficulties and as the journey from first symptom onset until receiving the final diagnosis includes unnecessary tests, procedures, misdiagnosis, and prolonged time to diagnosis, it becomes a “diagnostic odyssey” (Jefferies, 2024). Diagnostic odyssey is a generic term that can describe a long diagnostic journey for any disease; however, it has been associated primarily with rare diseases in the literature. The reason for this correlation is that it is a common challenge in communities with rare diseases. According to the NIH, there are around 7,000 rare diseases (Phillips et al., 2024), and the estimated number of rare disease patients in the United States (U.S.) is 30 million ( Yang et al., 2022). The average time to diagnosis (TTD) of rare diseases is 4-5 years or even longer, depending on the type of rare disease (Phillips et al., 2024). Ehlers-Danlos Syndrome (EDS) is one of the many rare diseases experiencing an average TTD of 10-12 years (Trudgian et al., 2024). Ehlers-Danlos Syndrome (EDS) is a group of genetic disorders that are classified into 14 subtypes. EDS affects the connective tissues and physically manifests as joint hypermobility, fragile skin, and skin hyper-elasticity (Doolan et al., 2024).
The rare disease economic burden on the healthcare system in the U.S., estimated by Yang et al. in 2019 for only 379 rare diseases, was projected to be $997 billion. Yang et al. categorized the cost as a “direct medical cost of $449 billion (45%), $437 billion (44%) in indirect costs, $73 billion in non-medical costs (7%), and $38 billion (4%) in healthcare costs not covered by insurance.” ( Yang wt al., 2022). For an established EDS patient, the estimated excess healthcare cost in 2021 was $21,100, and this does not include indirect costs and non-medical costs (Schubart et al., 2024). These studies are limited in the sense that they do not take into account the extra burden of the diagnostic odyssey.
Diagnosing EDS is further complicated by its 14 subtypes, each with unique severities, genetic mutations, heterogeneous clinical presentations, and low individual prevalence. Vascular Ehlers-Danlos Syndrome (vEDS) is one of the most severe subtypes of EDS and shows a prevalence between 1 in 50,000 and 1 in 200,000 (Schubart et al., 2024). The vEDS community is one of many communities suffering from prolonged diagnostic odyssey and TTD. This research paper focuses on the disparity of diagnostic odyssey and TTD in vEDS and will delve deeper into analyzing the reasons behind it and providing recommendations to resolve these disparities.
DIAGNOSTIC ODYSSEY
Genetic Causes of vEDS
vEDS, also known as type IV, is a genetically inherited disease that occurs at the onset of infancy. It is caused by a mutation in the COL3A1 gene or, in rare cases, COL1A1 (Frank, 2020). The mutation in COL3A1 and COL1A1 leads to defects in collagen III and collagen I, respectively (Malfait et al., 2017). Some studies discuss de novo mutation, which means that a spontaneous mutation may have occurred in the egg or sperm before fertilization. As a result, the patient will not have a family history of vEDS. The estimated frequency of having a de novo pathogen is between 42.4 – 50.8% (Legrand et al., 2019).
More than 500 mutations in COL3A1 can lead to vEDS. The most common mutation is the glycine residue mutation in the canonical triplet repeat, which is found in about 65% of cases, while the other 35% of cases are typically caused by in-frame splice mutations. Both types of mutations cause Collagen III structural abnormality, leading to vEDS with high severity. The remaining 10% are milder types of vEDs. This mutation leads to a reduction in the secretion of collagen III extracellularly, resulting in fibrillar defects. In addition to the accumulation of abnormal collagen intracellularly developing, the endoplasmic reticulum is also enlarging (Omar et al., 2021).
Clinical Presentation of vEDS
The clinical presentation of vEDS is heterogeneous. The patient can show facial characteristics such as eye protrusion, thin lips, sunken cheeks, and a pinched nose. Also, they may show cutaneous symptoms, such as easy bruising unrelated to trauma and thin, translucent skin, predominantly on the upper torso and abdomen, with abnormally visible veins. Wound healing may be delayed, resulting in widened, papyraceous scars, particularly over prominent bony pressure points (knee). Extremities, particularly hands, may appear prematurely aged (acrogeria), and talipes equinovarus (clubfoot) can occur (Malfait et al., 2017).
The complications of vEDS most likely appear in the late adolescent years; this may include major organ ruptures such as arterial, intestinal, uterine, liver, and spleen ruptures. Arterial dissections, aneurysms, arteriovenous fistulas, and spontaneous carotid-cavernous fistulas are possible outcomes. Digestive complications include spontaneous perforations of the sigmoid colon. Pneumothorax/hemopneumothorax is also one of the complications of vEDS (Malfait et al., 2017).
Time for Diagnosis
vEDS age of diagnosis between males and females is 28.2 ± 17.4 years and 29.4 ± 15.1 years, respectively. Individuals with a family history of vEDS (not including children with vEDS) were younger at the age of diagnosis compared with those without a family history (21.3 ± 13.6 years vs 30.2 ± 13.7 years; P = .008). Given that vEDS is a genetic disease and has infancy onset, the time to diagnosis is relatively high, especially with the new era of next-generation sequencing (Shalhub, 2020).
Diagnostic Criteria
In 2017, clinical diagnostic criteria were established to help guide the offering of genetic testing. It states that vEDS can be suspected if an individual has one of the primary diagnostic criteria or many of the minor diagnosis criteria. The major diagnostic criteria include a family history of vEDS, arterial aneurysms, dissection or rupture, intestinal rupture, uterine rupture during pregnancy, spontaneous sigmoid colon perforation without known cause, or carotid-cavernous sinus fistula (CCSF) formation in the absence of trauma. The minor criteria include the previously mentioned clinical presentation, such as facial characteristics, translucent skin, acrogeria, easy bruising, and early-onset varicose veins, In addition to hypermobility of minor joints, presentations can also include tendon/muscle rupture, pneumothorax/hemopneumothorax, Keratoconus, gingival recession and gingival fragility chronic joint subluxations/dislocations, congenital dislocation of the hips and talipes equinovarus (clubfoot) (Malfait et al., 2017).
Evaluation Of The Diagnostic Criteria
The International 2017 EDS criteria highlight the importance of next-generation sequencing in diagnosing EDS. The paper discussed molecular testing such as Sanger sequencing, targeting resequencing of a gene panel, whole exome sequencing (WES), or whole genome sequencing (WGS) to verify a clinical diagnosis (Malfait et al., 2017). Despite the progress made through establishing diagnosis criteria for vEDS based on visible symptoms, the vulnerability of vEDS patients lies in the silent symptoms, organ fragility, and disease progression with time that leads to major events. “The characteristic facial features are often subtle or absent and therefore the diagnosis of vEDS is delayed until after patients present with devastating sequelae” (Maraj et al., 2018). This means that many cases are not diagnosed until one of the major symptoms is observed, such as arterial, intestinal, or uterine rupture, which are more likely to occur in the late teenage years. At this point, hospitalization and medical intervention are needed. The major cause of death is arterial dissection or rupture with organ failure (Byers et al., 2017). Byers et al. state that individuals who don’t have a family history are most likely to be diagnosed post-mortem (Byers et al., 2017). Therefore, if physicians restrict offering genetic testing to this criteria, there will be delayed diagnosis, misdiagnosis, and a higher mortality rate. By the time the patient is diagnosed, the patient will have already developed devastating sequelae.
A study executed by Pepin et al. in 2000 showed a median survival of 48 years. Between 2000 and 2017, an observational study by Frank et al. showed the median survival age for vEDS was around 50 years (Buso et al., 2024). This raised the question of whether early diagnosis can make a difference. According to Buso et al., “vEDS management has significantly improved both in terms of the prevention and management of complications” (Buso et al., 2024). In addition, some evidence suggests that getting the proper diagnosis and clinical management can improve vEDS patients' survival rate (Bowen et al., 2023). For example, a study performed by Frank et al. where 90% of patients were treated with celiprolol showed significant improvement in survival compared to the no-treatment group. (72.4% vs. 52.2%, respectively; p < 0.001). Also, two-thirds of patients remained clinically silent despite a large number (51%) with previous arterial events or arterial lesions at molecular diagnosis (Frank et al., 2019). Another cohort study was done on 180 patients (97 females and 83 males). Patients on beta-blockers and angiotensin receptor blockers had a statistically significantly lower clinical progression score than those not on medication. Survival at 5 years was 96.53% for those on medication and 42.69% for the control group, suggesting a reduction in vascular events from this therapy. These results were even with more patients with vascular events at baseline (36%) compared to those without treatment (20%) (Bowen et al., 2023). However, the study by Frank et al. had some limitations, such as a small sample size and lack of randomization.
Emergency Care
The multifaceted nature of vEDS has an additional layer of unawareness among healthcare professionals: when it comes to emergency care, unfamiliarity with the vEDS can lead to risking patients' lives. Surgical intervention can cause complications; therefore, conservative management options should be considered. Bowen et al. provided patients in their cohort studies with “emergency information for medical professionals’ cards” so that appropriate measures could be taken in case emergency care was needed (Bowen et al., 2023). This is an excellent measure to handle emergency care unawareness; however, this measure can not be done without a timely diagnosis.
Diagnosis
Even among experienced clinicians, vEDS is difficult to diagnose due to its rarity and clinical presentation, which overlaps with other diseases (Bowen et al., 2023). Therefore, molecular testing is required for confirmation. The 2017 EDS diagnostic criteria discuss using several types of molecular testing in EDS. Understanding the features and the cost of each can be valuable in determining the appropriate test that can resolve the diagnostic odyssey.
Multi-Gene Panel Test
One effective method for diagnosis is a Multi-gene panel, which is a high-throughput method of DNA sequencing for the parallel sequencing of multiple genes. It is effective if there is a suspected specific condition or condition. It can be efficient and cost less than traditional Sanger sequencing methods (Lynce et al., 2016; Ishida et al., 2024). Multi-gene panel varies according to the number and type of genes and the company providing the test. It ranges from $250 to $1850.
Sanger Sequencing
The Sanger method only sequences a single DNA fragment at a time. Weerakkody compared Sanger Sequencing and New Generation Sequencing (NGS) and showed the NGS panels newly identified seven pathogenic or likely pathogenic variants and 18 Variance of uncertain significance (VUS) that had not been detected by phenotype-guided Sanger sequencing (Weerakkody, 2024).
Targeting Resequencing Of A Gene Panel
Targeted sequencing (TS) panels focus on specific clusters of genomic regions, reducing data burdens and minimizing the bioinformatics demand required. This approach simplifies data interpretation while providing excellent coverage depth. TS panels also offer lower costs and faster turnaround times (Pei, 2023).
Whole Exome Sequencing
The exome consists of all coding nuclear DNA sequences, including approximately 180,000 exons transcribed into mature RNA. Although the exome makes up only 1% to 2% of the human genome, it contains the majority of known disease-causing variants. Exome sequencing can be used to identify and analyze all protein-coding nuclear genes in the genome. Currently, it allows for the sequencing of approximately 95% of the exome (Legrand, 2019).
Whole Genome Sequencingg
The human genome consists of coding and noncoding sequences from nuclear and mitochondrial DNA. While nuclear DNA encodes more than 20,000 genes in humans, mitochondrial DNA encodes 37. Most of the 3.2 billion base pairs in the human genome are made up of repetitive or noncoding sequences, including noncoding RNAs, some of which have been linked to specific inherited disorders (Wallace, 2017).
Genome sequencing is a laboratory test that analyzes the entire sequence of coding and noncoding nuclear DNA. While Genome sequencing is significantly more expensive than exome sequencing due to the high cost of data analysis, the diagnostic utility for both methods is similar, ranging from 20% to 30%. Although genome sequencing can detect variants outside coding regions, determining the pathogenicity of these variants is often challenging. As a result, most confirmed pathogenic variants identified by genome sequencing are found within exons (Wallace, 2017).
Newborn Screening (NBS)
Biochemical analysis of dried blood spots is used in NBS (Ding, 2022), which is currently used to screen for 50 genetically inherited disorders, whereas next-generation sequencing is typically used as a second tier. However, next‐generation sequencing (NGS) can rapidly and cost-efficiently analyze larger panels of genes. Nurchis et al. suggest that wider use of WGS may minimize diagnostic delays and facilitate the timely implementation of appropriate treatments(Nurchis, 2024).
RECOMMENDATIONS
Emergency Care Awareness
The medical ID card is beneficial for emergency care awareness. This can mitigate the risks associated with emergency admission of a vulnerable group such as that of vEDS, where possible organ ruptures and failure will, at some point, lead to the need for emergency care. Appropriately identifying the vEDS can allow the emergency team to take proper measures. However, since the vEDS population suffers from prolonged TTD and almost half of vEDS cases are de novo. Therefore, this measure can only be useful for diagnosed vEDS patients.
Decreasing Diagnostic Odyssey
Next-generation sequencing is a valuable tool that can help in the disparities between long-term diagnosis and misdiagnosis. The Every Life Foundation for Rare Diseases estimates the cost of prolonged time to diagnosis and loss of productivity in pre-diagnosis years between $86,000 and $517,000 per patient cumulatively (Cost of delayed diagnosis in rare disease, 2023). Redirecting the money spent on unnecessary tests, procedures, and clinical visits to genetic testing as a first measure in the cases of subtle signs and symptoms can lead to proper diagnosis and can help reduce the disparities of diagnostic odyssey among rare disease patients generally.
Whole Genome Sequencing for Newborn Screening
vEDS is a disease that has infancy onset; therefore, newborn screening using Whole Genome sequencing will help with the early diagnosis of vEDS and result in better management of vEDs and serve the de novo cases of vEDS.
CONCLUSION
Vascular Ehlers-Danlos Syndrome (vEDS) exemplifies the challenges of rare disease diagnosis, often resulting in a lengthy diagnostic odyssey. The complexity of the disease, with its subtle and heterogeneous clinical presentations, especially in cases with de novo mutations, leads to prolonged time to diagnosis (TTD) and increased mortality. While the International 2017 EDS diagnostic criteria help guide clinical suspicion, they fall short in capturing all cases, particularly those without a family history or clinical symptoms, contributing to misdiagnosis or late diagnosis after serious complications.
Early and accurate diagnosis is crucial for vEDS due to its high morbidity and mortality, primarily from vascular complications. The advancement of molecular diagnostic tools such as next-generation sequencing (NGS), including multi-gene panels, whole-exome sequencing (WES), and whole-genome sequencing (WGS), has significantly improved diagnostic accuracy. Early genetic testing can reduce the diagnostic odyssey by identifying vEDS in asymptomatic individuals or those with subtle symptoms, leading to better clinical management and improved survival rates, as studies on beta-blocker therapies have shown.
Implementing whole-genome sequencing in newborn screening programs holds promise for the early detection of vEDS and other rare genetic disorders, particularly for de novo cases. This proactive approach could prevent the unnecessary healthcare burden caused by prolonged TTD, reduce patient suffering, and lead to earlier, life-saving interventions.
Addressing the diagnostic odyssey in vEDS and other rare diseases requires a shift toward more widespread and accessible genetic testing as a first-line diagnostic tool. This strategy and increased awareness in emergency care settings can improve patient outcomes and alleviate the economic burden on healthcare systems.
REFERENCES
Bowen, J. M., Hernandez, M., Johnson, D. S., Green, C., Kammin, T., Baker, D., Keigwin, S., Makino, S., Taylor, N., Watson, O., Wheeldon, N. M., & Sobey, G. J. (2023). Diagnosis and management of vascular Ehlers-Danlos syndrome: Experience of the UK national diagnostic service, Sheffield. European journal of human genetics: EJHG, 31(7), 749–760. https://doi.org/10.1038/s41431-023-01343-7
Blue Print Genetics. (2018, July 26). Ehlers-Danlos Syndrome Panel. Https://Www.Ncbi.Nlm.Nih.Gov/. NIH National Library of Medicine. Retrieved from https://www.ncbi.nlm.nih.gov/gtr/tests/552678/.
Blue Print Genetics. (n.d.). Pricing. Blueprintgenetics.Com. Retrieved from https://blueprintgenetics.com/pricing/.
Buso, G., Corvini, F., Fusco, E. M., Messina, M., Cherubini, F., Laera, N., Paini, A., Salvetti, M., De Ciuceis, C., Ritelli, M., Venturini, M., Chiarelli, N., Colombi, M., & Muiesan, M. L. (2024). Current Evidence and Future Perspectives in the Medical Management of Vascular Ehlers-Danlos Syndrome: Focus on Vascular Prevention. Journal of Clinical Medicine, 13(14), 4255. https://doi.org/10.3390/jcm13144255
Byers PH. Vascular Ehlers-Danlos Syndrome. 1999 Sep 2 [Updated 2019 Feb 21]. In: Adam MP, Feldman J, Mirzaa GM, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2024. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1494/
Byers PH, Belmont J, Black J, De Backer J, Frank M, Jeunemaitre X, Johnson D, Pepin M, Robert L, Sanders L, Wheeldon N. 2017. Diagnosis, natural history, and management in vascular Ehlers–Danlos syndrome. Am J Med Genet Part C Semin Med Genet 175C: 40–47.
Ding, S., & Han, L. (2022). Newborn screening for genetic disorders: Current status and prospects for the future. Pediatric investigation, 6(4), 291–298. https://doi.org/10.1002/ped4.12343
Doolan, B. J., Lavallee, M. E., Hausser, I., Schubart, J. R., Michael Pope, F., Seneviratne, S. L., Winship, I. M., & Burrows, N. P. (2023). Extracutaneous features and complications of the Ehlers-Danlos syndromes: A systematic review. Frontiers in medicine, 10, 1053466. https://doi.org/10.3389/fmed.2023.1053466
Fulgent. (n.d.). Clinical Exome. Fulgent Genetics. Retrieved from https://fulgentgenetics.com/Clinical-Exome.
FRANK, D. M. (Ed.). (2020, April). Vascular Ehlers-Danlos syndrome. orphanet. https://www.orpha.net/en/disease/detail/286#menu
Genomics for life. (n.d.-a). Ehlers Danlos Syndrome (EDS) Panel. Genomicsforlife.Com. Retrieved from https://genomicsforlife.com.au/inherited-disease-screening/ehlers-danlos-syndrome-eds-panel
Ishida C, Zubair M, Gupta V. Molecular Genetics Testing. [Updated 2024 Mar 16]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK560712/
Invitae. (2021, July 14). Invitae Ehlers-Danlos Syndrome Panel. NIH National Library of Medicine. NIH. Retrieved from https://www.ncbi.nlm.nih.gov/gtr/tests/553788/.
Invitae. (2022, July 08). Invitae Connective Tissue Disorders Panel. NIH National Library of Medicine. NIH. Retrieved from https://www.ncbi.nlm.nih.gov/gtr/tests/597548/
Invitae. (n.d.-a). Invitae Ehlers-Danlos Syndrome Panel. Https://Www.Invitae.Com/. Invitae. Retrieved from https://www.invitae.com/us/providers/test-catalog/test-02313.
Invitae. (n.d.-b). Invitae Connective Tissue Disorders Panel. Https://Www.Invitae.Com/. Invitae. Retrieved from https://www.invitae.com/us/providers/test-catalog/test-434340.
Jefferies, N. (2024, February 13). Diagnostic odyssey in rare disease. NHS England. https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/the-diagnostic-odyssey-in-rare-disease/
Legrand, A., Devriese, M., Dupuis-Girod, S. et al. Frequency of de novo variants and parental mosaicism in vascular Ehlers–Danlos syndrome. Genet Med 21, 1568–1575 (2019). https://doi.org/10.1038/s41436-018-0356-2
Lynce, F., & Isaacs, C. (2016). How Far Do We Go With Genetic Evaluation? Gene, Panel, and Tumor Testing. American Society of Clinical Oncology educational book. American Society of Clinical Oncology. Annual Meeting, 35, e72–e78. https://doi.org/10.1200/EDBK_160391
Malfa, F., Francomano, C., Byers, P., Belmont, J., Berglund, B., Black, J., Bloom, L., et al. (2017). The 2017 international classification of the Ehlers–Danlos syndromes. Am J Med Genet Part C Semin Med Genet 175C: 8–26.
Mayo Clinic Laboratories. (2024, April 08). Ehlers-Danlos Syndrome Gene Panel. Https://Www.Ncbi.Nlm.Nih.Gov/. NIH National Library of Medicine. Retrieved from https://www.ncbi.nlm.nih.gov/gtr/tests/603740/
Mayo Clinic Laboratories. (n.d.). Ehlers-Danlos Syndrome Gene Panel, Varies. Www.Mayocliniclabs.Com. Retrieved from https://www.mayocliniclabs.com/test-catalog/overview/617253#Overview.
National Cancer Institute (NCI), https://www.cancer.gov/publications/dictionaries/cancer-terms/def/diagnosis
Phillips, C., Parkinson, A., Namsrai, T. et al. (2024). Time to diagnosis for a rare disease: managing medical uncertainty. A qualitative study. Orphanet J Rare Dis 19, 297. https://doi.org/10.1186/s13023-024-03319-2
Trudgian R, Flood T. (2024). An exploration of the journey to a diagnosis of Ehlers-Danlos Syndrome (EDS) for women living in Australia. PLoS One. 19(7):e0307574. doi: 10.1371/journal.pone.0307574.
Wallace SE, Bean LJH. (2017). Genetic Testing: Current Approaches. GeneReviews® [Internet]. Seattle (WA): University of Washington. https://www.ncbi.nlm.nih.gov/books/NBK279899/
Yang, G., Cintina, I., Pariser, A. et al. (2022). The national economic burden of rare diseases in the United States in 2019. Orphanet J Rare Dis 17, 163. https://doi.org/10.1186/s13023-022-02299-5