What is Ehlers-Danlos Syndrome? We explain the common gymnast condition which Larry Nassar 'used as an excuse' to touch his victims

EDS is a genetic disorder that makes skin, joints and connective tissues more flexible 

It is likely more common among gymnasts and athletes who display unusual flexibility 

One gymnast claimed that Nassar claimed that he could tell she had the condition based on an invasive pelvic exam

But, an expert says, that would not be part of a proper diagnostic procedure

During Larry Nassar's sexual abuse trial and sentencing, victims' harrowing stories have brought to light Ehlers-Danlos Syndrome (EDS), a condition that is common among gymnasts, but poorly understood.   

One gymnast, Melody Posthuma Van der Veen, claims that he told her she might have EDS because he was able to 'put his whole hand' inside of her, the Huffington Post reported in a tweet.   

The revelation drove a surge in Google searches for EDS over the last month, as the public tried to understand what a connective tissue disorder that is common among gymnasts had to do with sexual abuse. 

Here, we explain the hyperflexibility condition and why Nassar's aggressive pelvic exam was not part of the diagnostic criteria for it. 

Gymnast Melody Posthuma Van der Veen (center) testified against Dr Larry Nasser on Thrusday in Lansing Michigan. She told the Huffington Post the the physician claimed he could tell she had EDS by the elasticity of her vagina during an allegedly inappropriate pelvic exam 

What can appear to be biological advantage also sometimes comes with fragile and unusually stretchy skin. 

But Lara Bloom, international executive director of the Ehlers-Danlos Society, said that although Van der Veen's tissue might be more 'lax' if she had the disorder, she does not 'think it would be appropriate for someone to say that...it is not part of the diagnostic criteria.'

About one in every 5,000 people around the world has some form of EDS.

As these are genetically inherited conditions, gymnastics does not cause EDS, rather, people who excel in the sport like 'naturals' may in fact be more likely to have a mutation that makes them more flexible. 

There are 13 types of EDS, the most common of which are classical EDS and hypermobility EDS.

The condition is mild in some - causing only slight looseness in the joints - while in others, weaker blood vessels can tear, leading to life-threatening internal bleeding. 

Larry Nassar (pictured) is being sentenced for sexually abusing athletes he treated, including team USA gymnasts and a victim who says he told her she had EDS based on an inappropriate pelvic exam he gave her

Searches for 'Elhers Danlos' Syndrome rose over the last month, according to Google Trends

All EDS affect connective tissues, including the skin, joints and other tissues.

Some forms relate to collagen production and composition problems, though the particular issue varies widely. 

When collagen is disrupted, the body's many connective tissues - including cartilage, tendons, fat and bones - may falter and fail. 

All forms of EDS generally cause instability in the joints and tissue, which can stretch and bend past the typical ranges of motion.  

While the looser tissue allows greater flexibility, it also leaves people suffering the disorder more vulnerable to dislocating or spraining joints. 

Simply being 'bendy' is often the first sign that someone might have the EDS. 

For example, those who can easily use one hand to pull the thumb of the other out and down so that it's parallel to the wrist, likely have some form of hyperflexibility. 

In some forms, corrupted collagen causes abnormal scarring, sometimes referred to as 'cigarette-paper' scarring, because the skin may look extremely thin and delicate, wrinkling or rippling like tissue paper.

Otherwise healthy, unscarred skin may also look and feel much softer or more velvety than the average person's.  

In addition to joints, skin and other soft tissues may be more flexible and stretchy in people with EDS. 

EDS can cause sufferers' skin to look particularly thin and delicate when scars form 

Some studies have suggested that there may be links between dysfunctional pelvic floor muscles and EDS, but the findings do not suggest that the performance of these muscles can be used to diagnose the condition. 

Dr Nassar's alleged pelvic exam of gymnast Melody Posthuma Van der Veen, from Michigan, would not likely be relevant to diagnosing the disorder.  

However, she and other gymnasts, researchers have reported, should be carefully screened for the disorder, as their flexibility could be a prominent symptom. 

The 12 more rare forms of EDS can be diagnosed through genetic testing, but there is not such test for hypermobility EDS.    

Without diagnosis through genetic testing and careful screening, it is impossible to know which form - if any - these athletes might be suffering. 

Hypermobility EDS is difficult to distinguish from other hypermobility spectrum disorders, but a pelvic exam would not be sufficient to determine that Van der Veen or other athletes were suffering from any such disorders.  

In the absence of preventative care, they could irreparably damage their joints, leading to permanent losses of mobility and chronic pain.