Professional ballet dancers often have gene variants of the connective tissue

reference

Vera Am, Peterson Le, Dong D, et al. High prevalence of connective tissue variants in professional ballet. am J Sports Med . 2020; 48 (1): 222-228.

objective

In order to determine the prevalence of gene variants of the connective tissue in professional ballet dancers and to understand whether an increased joint hypermobility or the presence of gene variants has improved the position of a ballet dancer within a company.

draft

cross -sectional Examination

participant

This study included 51 adults, male (n = 26) and female (n = 25) professional ballet dancers of a large ballet company in a big city, 32 of which completed a genetic test. The age ranged from 18 to 35 years with an average of 23.9 years.

study parameters evaluated

The authors assessed all 51 participants on generalized joint hypermobility based on a beigal and ankle selection performance scores and the Brighton criteria, a clinical instrument that supports the diagnosis of generalized joint hypermobility syndromes. Thirty -two participants approved genetic tests and were examined on 60 different connective tissue variants. These variants were divided into the following clusters: Ehlers-Danlos-Syndrome (EDF); Marfan; Loeys-Dietz; Bethlem myopathy; and morphology of muscle, skeleton and connective tissue.

Primary result measurements and key results

of the 32 dancers who took part in the DNA analysis had 28 (88%) at least 1 variant in the 60 genes tested. The researchers found 80 variants in total. With at least one dancer, they found a variant in 26 of the 60 genes. The Brighton criteria were positive in 31.3 % of the participants, and 53.1 % had a positive Beighton score. No other connective tissue disease variants were found.

The authors found no advantage within the company (headmaster to apprentice) for those with connective tissue variants. They found that dancers with variants in the clusters Marfan and Loeys-Dietz had a reduced hip participation.

Comment

hereditary disorders of the hypermobil spectrum (HSD) are an increasing cause of chronic pain and multi -systemic dysfunctions. ^{1 This study helps to define the prevalence of so far not reported and not reported connective tissue variants. The researchers evaluated 8 genes, which has never been reported or reported that they occur at <0.0001 % of the population.}

This data is amazing. Either these gene variants of the connective tissue are significantly more often reported than before, or ballet dancers are significantly overrepresented, or both. This information can help doctors who suspect secondary pain causes to search for the underlying HSD by raising a corresponding medical history. It can be helpful for screening to simply ask your patients whether they have done ballet, gymnastics or cheerleading in the past.

There are many myths about HSD. For example, patients do not need a prehistory of Open joint cluxation to meet the diagnostic criteria of 2017 for the hypermobile Ehlers-Danlos syndrome (HEDS) or HSD. ^{2 Doctors can overlook HSD in their differential in patients with chronic pain due to the perceived rarity of these disorders. Twenty years ago, a prevalence of 1/5,000 (00002 %) was given, 3 and recent studies indicate it in 1/500 (0.002 %). 4 The true prevalence is unknown due to the lack of recognition and use of suitable diagnostic criteria. This inadequate understanding has led to increased patient disorders and misdiagnoses such as fibromyalgia, central pain sensitization and/or psychiatric disorders.}

This study is significantly restricted by the lack of an age -adapted control population. Age -adapted controls could have helped to define whether under -reported variants in ballet dancers are really overrepresented. While it is impressive that 88 % of the participants had an identifiable variant, many of the most common variants are not reported in the human gene mutation database or ensembl, and therefore we have no way to know whether these variants are significantly higher compared to a non-ballet population. For example, the most frequently identified variant was the TTN gene, which is involved in muscle morphology. This variant was found 22 times, but the frequency in the general population is unknown. In addition, no data on ethnicity is recorded, which is likely to affect the frequency of variants.

This data is amazing. Either these gene variants of the connective tissue are significantly more often reported than before, or ballet dancers are significantly overrepresented, or both.

The authors unfortunately did not report or analyzed the patients who were available> 1 variant. This was probably due to the low sample size. For example, they found 3 variants in the tnxb gen, 2 an der Adamts2 2 an col1a2 and 1 at Col1a1 . These are associated with the following forms of the Ehlers-Danlos syndrome: classic-like, dermatosparaxis, heart valve and classic. The authors should have carried out echocardiograms for all dancers who had Marfan, EDS or Loeys-Dietz genes. The authors do not comment on whether these dancers with well-known EDS variants would rather meet the Brighton criteria. If this information had been reported, you could help us better understand these diseases. This is probably available in your data, but is not reported.

This study used the outdated Brighton criteria from 1998 to identify participants with a hypermobilic disorder. ^{6 The Brighton Criteria were replaced in 2017. 7 The Brighton criteria were previously used to identify patients with benign joint hypermobility syndrome (BJHD). We no longer use this terminology, and this disorder is now called hypermobile spectrum disorder (HSD), which includes the hypermobile Ehlers-Danlos syndrome (HEDS).}

In addition, the researchers did not use validated results to evaluate chronic pain. Although hypermobility can have advantages - for example, improved performance in a discipline that requires excessive joint movements such as ballet - it is important to understand that this can have weakening consequences. Based on clinical experience with more than 1,000 HSD patients, I suspect that more affected patients due to severe pain, joint instability, injuries and the presence of other comorbid diseases such as. Pots) or mast cell activation syndrome (MCAS).

The researchers still clarify the true frequency of these overlapping comorbidities, but there is more and more indications that disabilities in patients with multi -system diseases are greater. ^{12 doctors must understand that these disorders can lead to global disability. Integrative medicine is well positioned to help these patients improve the joint stability and function of the autonomous nervous system and the immune system if the practitioner is willing to dive deep into the literature.}

FAZIT

Overall, this study improved our understanding of genetic variants of the hypermobil connective tissue. Future studies must include adapted controls to define the true incidence of ballet dancers compared to the general population. Ultimately, this work is unable to support their hypothesis that variants within hypermobility-associated genes would be overrepresented in professional ballet dancers. We also have to examine the ethnicity of dancers, validated pain scales and the quality of life. The current diagnostic criteria and the nomenclature of disorders of the hypermobil spectrum and the hypermobile Ehlers-Danlos syndrome should be used. While this study does not compare the prevalence of HSD with age-affected control persons, clinicians should still consider asking their patients with chronic pain about previous ballet, gymnastics and cheerleading participations.