Some illnesses are invisible.

Emma Beal, who was active in the Halifax and Rastrick communities, suffered from a progressive mitochondrial disease. But behind closed doors, she would often be bed-bound.

It is estimated that one in 4,000 people has the genetic disease, but there were only three people in the world with Emma’s specific form of it, which was called combined oxidative phosphorylation deficiency 16.

One example of the disease that captured international attention was Charlie Gard, who had infantile-onset encephalomyopathy mitochondrial DNA depletion syndrome (MDDS). The baby, who had inherited the faulty RRM2B gene from his parents, was blind, deaf and could not move or breathe without a ventilator.

But Emma’s death, on September 28, at just 28 years old proved once again just how fatal other forms of the disease can be.

Portrait of Emma Beal by Joanna Flynn. It was used for the order of service at her funeral.

Speaking from the family’s home in Rastrick, her mum Christine Beal: “One of the hardest things was when people judged her.

“When you say cancer, they understand but when you say mitochondrial disease, it’s like a tumbleweed moment. It’s almost awkward.

“When we used her disabled parking badge, we’d often get disapproving looks when we walked away.

“The disease is debilitating – she wasn’t tired because she was lazy.

“Now, they feel bad.”

The inheritance, on-set and symptoms vary from patient to patient and there is no cure.

In nearly every cell in the body, mitochondria are responsible for producing energy that the cell needs to function. Cells make up tissues and organs, for example the heart and liver. They are like power stations in bodies, supplying the energy every cell needs to function.

If cells do not have energy then the tissues or body organs that the cells are made up of do not work properly. In the same way, if power stations do not produce enough energy there will be areas of blackout, where parts of the country cannot function.

Emma Beal and her fiancé Paul Bates, an A&E nurse, on one of their holidays to Turkey.

Mitochondrial diseases are sometimes caused by mutations in the mitochondrial DNA that affect mitochondrial function. Other mitochondrial diseases are caused by mutations in genes of the nuclear DNA.

For Emma, the faulty MRPL44 gene was inherited from just her mum – something very rare.

As a child, Emma was quite clumsy and broke bones easily, but she didn’t become seriously ill until May 2010 when she was sitting her exams for a BA Animal Science degree.

She began suffering from headaches and fatigue.

After visiting Calderdale Royal Hospital, she was found to suffer from a serious heart condition called hypertrophic cardiomyopathy, as well as a condition called leukodystrophy – a condition where white matter on her brain affects her nervous system.

As she lay alone in a hospital bed, a doctor told the then-21-year-old that she had ‘the heart of an 80-year-old’. She was even advised that hypertrophic cardiomyopathy can bring on sudden arrhythmic death syndrome (SADS).

Christine, who is a Conservative councillor and also office manager for MP Craig Whittaker, said: “From day one, they said it would be very rare to find two major organs with major damage without something underlying.

Paul Bates, Emma Beal, Dale and Beth Ellis, Peter and Christine Beal in 2015. Photo by: Chris Chambers.

“She was absolutely shocked and scared because you think you have a normal future and health ahead of you and all of a sudden you have this question mark above your health.”

Emma went on to develop other symptoms, such as hemiplegic migraines, osteoporosis, balance problems and tremors, as well as losing full control of her bodily movements.

She had to go for check-ups in Manchester every six months and in London every 12 months.

It took 18 months to find out that she wasn’t susceptible to SADS and nearly five years before she was finally diagnosed with a mitochondrial disorder called Combined Oxidative Phosphorylation Deficiency 16.

In the meantime, she was determined to remain active, despite being unfit to work and needing to use a wheelchair occassionally. She volunteered for Calderdale Council, Scope Aspire Services in Halifax, the RSPCA charity shop in Brighouse and was even her 87-year-old grandad’s carer.

“Some days she had good days and sometimes she didn’t and she would be knocked out for the day,” said Christine.

Emma Beal was one of just three people in the WORLD with this form of mitochondrial disease.

“She was an inspiration. She was so brave and she never complained.”

While on holiday in Turkey with her 31-year-old fiancé Paul Bates, Emma’s condition rapidly deteriorated and she suffered a cardiac arrest.

Christine, who flew to the country with Emma’s dad Peter and Paul’s mum Sue, said: “We went to say our goodbyes and we didn’t get a sense that she was there. We felt her around us and knew she had left her body.

“She died herself on the life-support machine that night. She had taken the decision out of anyone’s hands.

“We believe it was her destiny to help raise awareness of the disease.”

A charity has been launched by her family and friends to raise awareness and funds for mitochondrial research and has raised more than £8,000 already.

Find out more about My Mito Mission online at: .