Ehlers-Dahlos syndromes are disorders that affect connective tissues. They are both under-researched, and common co-occurring conditions in autistic people. We wanted to know more about how Ehlers-Danlos gets diagnosed (and overlooked) and the state of the research, so we spoke with autistic autism researcher Dr. Emily Casanova, who presented on this topic at INSAR 2019, the annual meeting of the International Society For Autism Research.

Thinking Person’s Guide to Autism: First you can tell us a little bit about you and your work?

Dr. Casanova: My work has two major foci. The first centers around the relationship between Ehlers-Danlos Syndromes (EDS)/hypermobility spectrum disorders (HSD) and autism, trying to tease apart their shared biology so we can better define and understand precisely what these overlapping conditions are. The second branch of my work focuses on the genetics underlying autism. I am particularly interested in the evolutionary patterns of these genes and their functions within prenatal development across species. Many rare genetic variations that are associated with autism occur in developmental genes, which are extremely old and are highly conserved across most species.

TPGA: How is Ehlers-Danlos diagnosed?

Dr. Casanova: EDS and the closely related HSDs are diagnosed primarily through physical assessment and taking patient histories. Genetic testing is also an option, and is currently used to rule out other hereditary connective tissue disorders (HCTD). There are different types of EDS, with the most common form being hypermobile EDS (hEDS). This type of EDS, as well as the related HSDs, are diagnosed using the hEDS Criteria Checklist, which you can find on the Ehlers-Danlos Society website:

Generalized joint hypermobility (GJH) (as defined by a score of 5+ for adults under 50 on the Beighton scoring system) is considered a central feature of these diagnoses, as well as chronic musculoskeletal pain and/or instability (see Criteria 1 and 2c). Other features associated with HCTD, such as effects to the skin, the heart, and the skeleton are also observed (Criterion 2a).

Finally, the clinician will note whether any 1st degree family members also meet criteria for hEDS.

These criteria were published in 2017 and are much stricter than previous iterations. The broad HSD category is also a new diagnostic entity that subsumes people with previous diagnoses of Joint Hypermobility Syndrome (JHS) or localized/historical features of hypermobility who have features of musculoskeletal pain/instability but don’t meet full hEDS criteria. Some individuals with a previous diagnosis of hEDS prior to the 2017 criteria change may also now fall under the HSD umbrella.

Although EDS was once considered a rare condition, occurring in about 1:2,500-5,000 people, most clinicians believe that the hEDS type is common, although prevalence estimates are not yet available in part due to the recency of changes in diagnostic criteria.

TPGA: Do you have a sense of how many subtypes of EDS are there, including related conditions like Hypermobility Spectrum Disorder?

Dr. Casanova: Currently, there are 13 recognized types of EDS, although that will probably continue to expand with time and further research. With the exception of hEDS, most forms of EDS have gene associated mutations and are believed to be rare conditions. (“Rare” is typically defined as occurring in no more than 1 in 2,000-3,000 people.) hEDS on the other hand is likely a common condition and there are currently no identified mutations associated with it (although that will probably change in coming years due to ongoing genetics studies).

HSDs are even more common than hEDS. Previous research suggests that generalized HSD (G-HSD), which are people who have GJH and musculoskeletal pain/instability but don’t meet Criteria 2a or 2b in the hEDS Checklist, occur in approximately 2% of the general population. Meanwhile, GJH occurs in about 20% of the population. It’s currently uncertain how many people have what is known as localized hypermobility, which is hypermobility in 1-4 joints but who don’t meet criteria for generalized hypermobility.

TPGA: What are some typical and atypical traits of EDS that people should look out for?

Dr. Casanova: The typical traits of hEDS are GJH, chronic issues with musculoskeletal pain and/or instability, and usually other effects to the connective tissue like soft mildly pliable skin, easy bruising, abdominal hernias, Marfan-like (“Marfanoid”) features such as long arms or fingers, and some mild heart malformations like mitral valve prolapse.

While these are currently considered the core characteristics of EDS/HSD, because connective tissue is in almost all parts of the body, it sometimes seems that there are few symptoms that can’t occur in association with these conditions. So rather than try to list them all here, I highly recommend following the blog, Oh TWIST!, by Jan Groh, which has an incredible wealth of information on EDS/HSD and related conditions:

TPGA: Does anyone have good statistics on the percentage of autistic people who also have Ehlers-Danlos?

Dr. Casanova: Unfortunately, there are few studies on this topic. One Swedish study back in 2016 estimated that approximately 3% of those with EDS in Sweden also have an autism diagnosis. However, because hEDS/HSD is predominantly diagnosed in women and autism is notoriously underdiagnosed in females, those are probably underestimates of co-occurrence. I personally suspect we may see as much as 10% overlap, but we are in desperate need of more research to determine whether this is the case.

Black-and-white headshot of Dr. Emily Casanova, a white woman with medium-dark, chin-length waved hair.
Dr. Emily Casanova

TPGA: What advice do you have for people who suspect they have EDS but can’t get a diagnosis? (Besides venting on #DoctorsAreDickheads.) Why is it so hard to get a diagnosis for so many people?

Dr. Casanova: Circumstances are complicated. Many doctors are either unaware, untrained, or—worse—misinformed about what EDS/HSD is and how it presents. If a genetics center is available and taking referrals, that is often the best place to seek an assessment. Geneticists are usually very experienced in identifying and measuring physical malformations (e.g., hypermobility), as well as offering genetics services for those interested. However, any EDS-experienced clinician should be capable of performing an assessment.

Some genetics centers have unfortunately stopped accepting referrals for hEDS/HSD for two primary reasons: 1) because hEDS/HSD are common conditions (in contrast to the usual rare conditions that most geneticists see), these centers are being overrun with referrals, spreading resources thin; 2) because we have yet to identify rare mutations consistently in this population, geneticists often feel like there’s not much they can do, aside from perform a physical assessment and take a history.

Unfortunately, there are also those instances in which age-old prejudices that center around female-dominated conditions like EDS/HSD also play a role, leading to dismissal of patients’ concerns or, worse still, outright patient abuse. For a population that comes into frequent contact with the medical establishment due to complex ongoing physical problems, sadly there are few patients who have not experienced these unfortunate and painful events, leading to higher rates of medically-induced posttraumatic stress disorder (PTSD) in this population. Finding a supportive physician is therefore of paramount importance for those with EDS/HSD.

TPGA: What about BAPpy folks (Broad Autism Phenotype with a sub-clinical set of autistic traits)? Do they have a tendency towards EDS as well, as yet another one of those shared traits?

Dr. Casanova: There do seem to be a lot of BAP folks on the EDS/HSD spectrum. I’m not sure how often BAP individuals present with EDS/HSD symptoms, but I’d assume a portion of them do. We’re hoping in future to at least get an estimate of the frequency of BAP in EDS/HSD.

TPGA: Are you aware of any approaches like diet or exercise that can help improve the quality of life for people with EDS?

Dr. Casanova: A good book on physical therapy and exercise specifically for those with EDS/HSD is Living Life to the Fullest with Ehlers-Danlos Syndrome. Diet also can be a tricky issue for many with EDS/HSD because, with comorbid mast cell activation syndrome (MCAS), there’s considerable variability in how individuals react to different foods. Some people try a low histamine diet, others do a trial by error diet. For those who can handle it without GI side effects, I’m personally a firm believer in consumption of amino acids, such as things like bone broth.

Since in hEDS/HSD we seem to experience chronic inflammation and probably rapid turnover of connective tissues, it’s a good idea to supplement the diet so that the body has ample supply for repair. Antioxidants are also probably another helpful supplement, although be cautious about overdosing, but they are also important for cell repair. But most importantly, if the individual is experiencing gastrointestinal problems, an elimination diet may be helpful to determine if any particular food products are triggering reactions. However, not all GI issues are solely the result of an immune reaction but may be due to autonomic disorders associated with EDS/HSD, especially in the case of constipation and gastroparesis (slow emptying of the stomach), etc.

TPGA: Any other advice you’d want to give people who have EDS, from a personal or research perspective?

Dr. Casanova: If you have a current diagnosis of hEDS (based on the 2017 criteria), I highly recommend trying to enroll in the Hypermobile Ehlers-Danlos Genetic Evaluation (HEDGE) Study, which is a genetics study aiming to identify rare genetic variations that may occur in some people with hEDS. I’m not personally involved in this study, but the importance of this can’t be underestimated as this will help us better understand the biology(ies) of this common complex condition, how it may overlap with other hereditary connective tissue disorders, and hopefully how to better treat it and improve the quality of life for those on the hEDS spectrum.