Experience of diagnosis in mitochondrial disease

We’re proud to share the results of the first ever piece of Lily Foundation-led research – a study that looks in depth at how patients and families experience the moment of receiving a mitochondrial disease diagnosis.

Through our work funding a national Precision Medicine Diagnostics Project to improve diagnostic rates for mitochondrial disease, patient engagement work with our community highlighted the need to look more closely at the quality of the diagnostic experience, not just the science behind it.

It’s an aspect of the diagnostic odyssey that remains under-researched, particularly from the patient perspective. While most existing studies focus on caregivers, very few explore patients’ own experiences of receiving a diagnosis.

What our research shows about getting a mitochondrial disease diagnosis

Getting a diagnosis of mitochondrial disease is often described as a journey rather than a single moment. For many people, that journey includes months or even years of uncertainty, multiple referrals and emotional strain alongside the physical symptoms of the disease. [link to diagnosis page]

To better understand what this experience is really like, we carried out UK‑based research exploring how people experience the process of getting a mitochondrial disease diagnosis – before, during and after it happens. This page shares what we learned, why it matters and how it can help improve the diagnostic experiences in the future.

Why we did this research

Mitochondrial diseases are rare, complex and highly variable. Symptoms can affect many different parts of the body and may change over time, making diagnosis particularly challenging.

Previous research has shown that whilst receiving a diagnosis can bring relief and clarity, many people face:

• long delays before a diagnosis is reached
• multiple referrals to different specialists
• misdiagnoses along the way

We wanted to understand not just how long diagnosis takes, but how it feels – whether people feel listened to, supported and given clear information during what can be a stressful and emotional process.

Who took part

We ran an online survey in the UK in April and May 2025, inviting our community to share their experiences of receiving a mitochondrial disease diagnosis.

In total:

• 103 people took part
• Responses reflected experiences of children and adults, ranging from 7 months to 77 years old
• Participants included:
• people living with mitochondrial disease
• parents and caregivers
• partners and family members
• Some responses were given on behalf of people who had sadly passed away

This allowed us to capture a wide range of perspectives across the diagnostic journey.

What we found

A long journey to diagnosis

On average, participants reported waiting more than eight years from the onset of symptoms to receiving a mitochondrial disease diagnosis.

Many people began seeking medical help due to symptoms such as:

• persistent fatigue
• vision problems
• balance or co-ordination difficulties

Most participants saw multiple specialists, and some reported being referred to up to 11 different doctors before receiving an accurate diagnosis.

Misdiagnosis is common

Over one third of participants reported receiving at least one misdiagnosis before mitochondrial disease was identified. Common misdiagnoses included:

• diabetes
• mental health conditions
• cerebral palsy

This reflects how mitochondrial disease symptoms can overlap with more common conditions, particularly when multiple organ systems are involved or symptoms develop gradually.

Feeling heard and taken seriously matters

Many participants described feeling that their concerns were dismissed or not fully investigated, particularly early in the diagnostic journey. These experiences often left people feeling isolated and uncertain.

Participants reported that:

• feeling listened to helped them feel more supported
• being taken seriously may contribute to faster testing
• confidence in care was higher when doctors demonstrated awareness of mitochondrial disease

These findings suggest that communication and clinical curiosity play an important role in the diagnostic experience.

During diagnosis: how information is shared makes a difference

Most people received their diagnosis in person, but around 30% were told:

• over the phone
• by letter
• or by having results uploaded to the NHS app

Some participants felt unprepared when a diagnosis was delivered unexpectedly or without enough context. Those who received clearer information in advance felt better able to process the news and ask questions.

After diagnosis: gaps in support remain

Although many participants described positive medical support after diagnosis, feeling alone was common.

Key gaps included:

• limited information about patient organisations
• lack of psychological or emotional support
• long waits for specialist clinic appointments

Less than 60% of participants were referred to a specialist mitochondrial clinic. Some reported waiting up to two years for their first appointment, with little information or emotional support during that time.

Confidence in expertise has declined

Participants diagnosed more recently were less likely to feel confident in their diagnosing doctor’s experience with mitochondrial disease. Whilst around three‑quarters of those diagnosed before 2020 felt confident, this dropped to less than half among those diagnosed in the last five years.

One possible reason is increased access to genetic testing, which can now be ordered outside specialist services. While this is a positive development, it may also mean results are delivered by clinicians with limited experience of mitochondrial disease, affecting how supported people feel.

What this means for those seeking a diagnosis

Our findings highlight that diagnosis is not just a clinical process – it’s also an emotional and psychological experience.

Better diagnostic experiences may include:

• being listened to and taken seriously
• clearer explanations before and during diagnosis
• timely referral to specialist services
• access to psychological and peer support

Improving these areas could reduce distress and help people feel more confident and supported throughout their diagnostic journey.

What happens next

The next phase of this research will involve in‑depth, one‑to‑one interviews with people who took part in the survey. These conversations will help us better understand individual experiences and identify practical ways to improve diagnosis pathways and support.

Our goal is to use this research to:

• inform better resources
• support healthcare professionals
• improve the overall diagnostic experience for people affected by mitochondrial diseases.

Download the Plain Language Summary

Below you can read and download the full Plain Language Summary of this research, produced by Rare Disease Research Partners (March 2026) on behalf of The Lily Foundation:

Plain Language Summary (PDF)

This study was funded by unrestricted grants from Chiesi Ltd, UCB Pharma and Tisento Therapeutics. The funders had no role in study design, conduct, analysis or reporting.

Thank you

We are deeply grateful to everyone who shared their experiences with us. Their honesty and willingness to help are serving to shape a better diagnostic experience for others in the future.