Living with SANDO – a long road to diagnosis

42-year-old Mark shares his story living with Sensory Ataxic Neuropathy, Dysarthria, and Ophthalmoparesis (SANDO) disease, a rare mitochondrial condition that affects the brain, muscles, nerves and eyes. He discusses everything from the long road to diagnosis, his brother developing symptoms during adulthood, how it impacts him in daily life, and why he chooses to participate in health research.

Pictured: Mark, Rare Diseases BioResource volunteer

Rare conditions are, by nature, difficult to diagnose. This was certainly the case for Mark (42) who, up until his early 20s, was thought to be a clumsy kid with Dyspraxia; Dyspraxia is a common disorder that affects physical movement and co-ordination. It was only after Mark’s brother found out that he had problems with his eyes during adulthood that sparked the urge to get both brothers officially diagnosed.

Mark’s story

From an early age, Mark’s parents noticed that his balance was wobbly, and that he would often crash into things. However, they were not immediately concerned, as Mark never had any problems with the development of his speech and reading abilities. Throughout his teenage years, clumsiness simply became a part of his personality, something he would laugh off with family and friends, meanwhile local GPs assumed he had Dyspraxia.

As Mark completed his degree in Music at Southampton University, his older brother – who is now in a wheelchair – started to develop similar symptoms that were not present before. When Mark graduated at age 24, his brother went for an interview to join the police specials and, as part of his interview process, tests were carried out. The tests revealed that he had problems with his eyes and it was suspected to be neurological. This prompted both siblings to get checked out at the John Radcliffe Hospital in Oxford, particularly as the family were aware of Mark’s existing symptoms from childhood which meant it was possible that something genetic could be going on. The doctors thought they both had Ataxia, however with little information available they could not confirm this and had to wait until specific genetic tests were available to be conducted.

Eventually, the need for an official diagnosis came to a head when his brother’s work picked up on his symptoms and noticed that they affected him. At the same time, Mark and his partner wanted to explore fertility options so that they could start their own family, so they were desperate for answers.

Finally in 2016, the siblings got the official diagnosis via genetic testing carried out at the specialist London Ataxia Clinic. It was revealed that they both had a rare condition called Sensory Ataxic Neuropathy, Dysarthria, and Ophthalmoparesis (SANDO) syndrome.

What is SANDO?

SANDO is a very rare mitochondrial disease, typically associated with mutations in the gene POLG1. SANDO usually presents itself during adulthood and the symptoms caused and their severity can vary widely among individuals with the condition. The defining symptoms of SANDO are impaired coordination (ataxia), slurred speech (dysarthria), and weakness of the eye muscles (ophthalmoparesis).

SANDO is one of the conditions included in the Mitochondrial Diseases patient cohort at the NIHR Rare Diseases BioResource, led by Professor Patrick Chinnery. It is one of seventeen comprising the first phase of our Rare Diseases RNA Phenotyping project.

photo of doctor with blue medical gloves holding small 'rare disease' sign

How does Mark’s condition affect his daily life?

Mark, who is a remarkably positive person with a half-glass-full attitude, explained to us that he is fortunate enough not to need a wheelchair like his brother, and is able to manage most daily things himself, such as getting dressed. For him, it is his impaired eyesight and reduced ability to walk/use his feet that impacts him the most.

Weakness of the external muscles in his eyes causes him to see ghost images with a delay when looking at things, while difficulty with walking means he falls/trips over often and, for example, means he cannot walk his daughter to school by himself safely. He explained how working as a secondary school teacher, he would ‘laugh it off’ every time he tripped or fell, just like he has since young age.

Losing control over movement in his feet has meant that he cannot play the piano professionally (using a sustain pedal) anymore and now is only able only teach up until a certain grade. He also has ultimately had to stop driving, now carries a disabled badge, and requires a taxi to get to and from work.

Shockingly, on one occasion when Mark walked out of work to be collected by a taxi, he was refused pick up by the driver, who saw him stumbling out of work and assumed he was drunk, then drove off. This sequence repeated multiple times, before Mark called the taxi company and complained. He explained to the taxi company that his condition causes him to lose balance , but they didn’t seem to fully believe him.

Eventually the situation did get rectified, however it highlights the very need for knowledge surrounding such conditions, so that people are aware of hidden disabilities and do not jump to conclusions leading to discriminatory behaviour.

Why participating in research is important to Mark

Mark feels passionately about the lack of awareness over disabilities and rare conditions, as he believes knowledge is power and feels it is his responsibility to help the community – particularly as there are so few patients out there like him.

Upon receiving his official diagnosis, he was keen to get involved in research and clinical trials, especially as there is no known cure for SANDO. He first heard about the BioResource when he got invited to participate in the Rare Diseases RNA Phenotyping study, which aims to improve the diagnosis of patients that have Rare Diseases, to gain an insight into how rare diseases develop and potentially to lead to the development of new treatments.

For him, willingness to take part was an easy decision. He understands that, although research carried out today may not help him during his lifetime, he hopes that better awareness and treatment options will help the future generation living with the condition.

How can you help?

While rare disease research is ongoing, it is increasingly vital to raise awareness in order to educate the public about the reality of daily life for people living with a rare condition, who often have hidden disabilities.

We are incredibly grateful to Mark for spending time speaking with us and sharing his story. Thanks to people like him, we are able to carry out the research we do at the NIHR BioResource to further our understanding of the links between our genes, the environment, health and disease.

If you are interested in learning more about becoming an NIHR BioResource volunteer, please visit our website or get in contact on or call 0800 090 2233.

If you are a researcher interested in working with us to facilitate your experimental research or early phase clinical trials, including provision of data, samples and recall from over 250,000 participants by genotype and/or phenotype, please head to our website or contact us on

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