Primary Co-Enzyme Q10 Deficiency (PCQD) is a rare and progressive mitochondrial respiratory chain disorder, also known as Primary Ubiquinone Deficiency [1]. PCQD is hallmarked by low levels of coenzyme Q10 (CoQ10), a fat-soluble molecule called a lipid. There is wide variety in the genetic cause, age of onset, and symptoms experienced by affected individuals [2].
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Dr. Marni Falk speaks about PCQD
PCQD results from mutations to genes in the CoQ10 biosynthesis pathway, and therefore patients cannot make sufficient CoQ10 [1, 3]. CoQ10 is a fat-soluble antioxidant that is important for driving energy production in mitochondria and protecting against oxidative stress in the cell [4]. Lower levels of CoQ10 can result in decreased energy production and increased oxidative stress, but the exact mechanism causing the diverse symptoms of PCQD is still unclear [2]. Mutations in ten genes have been identified to cause PCQD, but it is possible for other gene mutations to result in this disease [1]. Mutations in genes outside of the CoQ10 biosynthesis pathway or non-genetic causes of CoQ10 depletion cause secondary CoQ10 deficiency [3]. PCQD is caused by autosomal recessive mutations, meaning that affected individuals have two copies of the mutated gene, with both parents passing down one copy of the mutated gene to the affected child. Individuals with only one copy of the gene are known as carriers, and asymptomatic. [1].
- Neurologic symptoms, such as encephalopathy, seizures, involuntary muscle contractions called dystonia, muscle stiffness called spasticity, loss of muscle coordination called ataxia, loss of brain cells and connection called cerebellar atrophy, and intellectual disability
- Hypertrophic cardiomyopathy (reported in COQ2-, COQ4-, and COQ9-related CoQ10 deficiency)
- Steroid-resistant nephrotic syndrome (SRNS), manifesting as proteinuria or high protein in the urine, that can evolve into end-stage kidney disease
- Damage to the retina called retinopathy (reported in PDSS1-, COQ2-, COQ4-, and COQ5-related CoQ10 deficiency) or optic nerve damage called optic atrophy (reported in PDSS1-, PDSS2-, and COQ2-related CoQ10 deficiency)
- Sensorineural hearing loss (reported in COQ6-, COQ2-, and PDSS1-related CoQ10 deficiency)
- Muscle weakness and exercise intolerance
- High serum, plasma, or cerebrospinal lactate concentration
- Molecular genetic testing
- Biochemical testing, including measurement of CoQ10 levels in skeletal muscle or respiratory chain complex activities in frozen muscle homogenates, to confirm molecular genetic testing or when molecular genetic testing does not establish a diagnosis
My Mito Story: Living with Primary Co-Enzyme Q10 Deficiency (PCQD)
Meet Julia, a 10-year-old from New York, who, like many of her peers, loves joking, dancing, binge-watching Disney+, and all things animals. “She’s a sweet, humble little girl,” said her mom, Jessica.
When we talked, mom and daughter were headed to see a new movie at the local theater. This – Julia growing up and being able to enjoy her childhood — was not something Jessica was sure she’d see. “When I got the test results, I thought I was going to lose my daughter,” Jessica recalled.
Three years ago, genetic testing revealed Julia was affected by Primary Co-enzyme Q10 (PCQD) deficiency, a rare mitochondrial disease where a patient lacks sufficient CoQ10, a substance that helps the body produce cellular energy. The disease is estimated to impact fewer than 1 in 100,000 people and can cause developmental issues, muscle weakness, seizures, and damage to vital organs.
Signs of potential problems started with mobility issues around age one. “She fell down a lot, was constantly tripping, and couldn’t run,” said Jessica.
Despite her concerns, doctors assured her that she should simply give Julia time.
Time, unfortunately, showed quite the opposite. As a preschooler, Jessica began noticing academic delays. An MRI confirmed ataxia, damage in her brain’s connections, which explained some of the physical and developmental issues, but doctors were unsure why.
As specialist after specialist looked for answers, Julia’s struggles continued.
By age seven, Julia lived with constant tremors. “She couldn’t brush her teeth. I had to dress her. She almost permanently lost her two front teeth from a fall. She had so many scars from accidents,” said Jessica.
At the urging of one of Julia’s therapists, Jessica convinced doctors to conduct another MRI, which showed significantly more damage in Julia’s cerebellum than only a few years earlier. Her neurologist would later order genetic testing, revealing the PCQD diagnosis.
Since there is no FDA-approved treatment, doctors put her on a “mito cocktail” – a mix of vitamins and supplements, including CoQ10 – and a ketogenic diet. For her part, Jessica connected with the United Mitochondrial Disease Foundation, which provided a variety of support programs and resources.
Today, thanks to that intervention along with intensive physical, occupational, and speech therapy, Jessica says Julia’s condition has somewhat stabilized. But issues persist.
“She really struggles with energy levels. Kids don’t want to miss a beat, but she’s easily fatigued by simple things like going up and down stairs,” said Jessica. “And her metabolism is through the roof. Her body burns a ton of energy, to the point where I think she’s becoming hypoglycemic. I have to remind her to listen to her needs, however she’s feeling.”
She hopes in the long run a cure, or even a treatment, will be able to help – if not for Julia, at least for other kids like her down the road.
“Yes, I hope for a cure one day. Right now, we just have to hope she doesn’t regress. Doctors just don’t know,” she said. “I would love it if one day she can run, like other kids. And I hope she doesn’t get sick. Or fall. But above all, I want to document her story, so maybe someday other families can understand what they’re going through.”
Jessica is aiming to channel what she’s learned from Julia’s diagnostic journey to help others like her. She’s currently finishing up a master’s program in public health administration.
“I hope to work in pediatrics, maybe even serving mito patients. I did a paper that made me think about opening a mito clinic in our neighborhood,” she said. “For now, though, my main goal is just to get her story out.”
Supplementation with high doses of oral Ubiquinol (CoQ10) can be an effective treatment, with the potential to attenuate symptoms and modify disease progression, especially if treated early. However, the response to oral CoQ10 supplementation is variable, possibly related to the onset of treatment. genetic cause of the disease, severity of the disease, and other unknown factors [1, 2].
BPM31510IV, a highly bioavailable intravenously administered coenzyme Q10 (CoQ10) formulation, is currently being studied as a treatment option.
In addition to CoQ10 supplementation, quality of life can be improved with symptom management, and surveillance for the emergence of new symptoms [1].
We are here to help. We suggest you reach out to our Support & Education Team – online, via email at support@umdf.org or phone at (888) 900-6486 – who can suggest a host of resources including doctors, disease specific support meetings, and more. They’ll also connect you with a UMDF ambassador, a fellow PCQD patient or family member if possible, who can help support and guide you through your questions.
- Get Support
Connect with our Support & Education Team online, via email at support@umdf.org or phone at (888) 900-6486.
- Check our clinical trials finder
Use our Clinical Trials Finder tool to see if you qualify for any clinical trials.
- Join our patient registry, mitoSHARE
We are actively recruiting PCQD families to participate in our patient registry, mitoSHARE. Patient registries like mitoSHARE are an integral part in charting a course toward treatments and cures for PCQD and other mitochondrial diseases. Next generation patient registries like mitoSHARE are an integral part of expanding that number. Click here to join.
- Become an advocate
Ask your representatives to prioritize mitochondrial disease research and support via the UMDF Advocacy Center. We’ll send regular action items so you – and your friends and family – can let Congress know where we need their support. Click here to sign up.
- Join the conversation online
– UMDF Social Media Support Groups: Facebook Support Group
– UMDF News & Updates: Facebook | Twitter | Instagram | YouTube
- Get involved
Join the fight by giving your voice, generosity, time, or energy. Click here to see how you can help.
UMDF is helping chart a path toward treatments and eventual cure of mitochondrial diseases like PCQD through:
- Research & Funding: UMDF has provided more than $18 million in research funding to find treatments for diseases like MERRF. UMDF advocacy has helped secure an additional $80 million in federal funding via the Department of Defense’s Peer Reviewed Medical Research Program.
- Data: Over two decades ago, UMDF pioneered patient registries for the mitochondrial disease community. Today, our next generation patient registry, mitoSHARE, is helping chart a path toward the treatment and eventual cure of mitochondrial diseases.
- Patient Support: Thousands of families just like you depend upon UMDF for support and education on diseases like PCQD. Attendance at our support meetings annually tops 7,000, including disease specific support meetings for families.
- Clinician Support: To help educate clinicians on diseases like PCQD, we feature monthly Bench to Bedside clinician seminars, host the annual Mitochondrial Medicine Symposium, support the Mitochondrial Care Network, and educate clinicians on our Mito U platform.
- Advocacy: UMDF is hosting an PCQD Listening Session with the FDA in July 2026, focused on elevating the voices of Primary Co-Enzyme Q10 Deficiency to regulators
UMDF is here to help. Contact the Support Line at (888) 900-6486 weekdays from 8:00am to 5:00pm EST to connect with our Patient Concierge. Or, via email contact support@umdf.org.
- Salviati et al., 2017 (last updated 2023). Primary Coenzyme Q10 Deficiency Overview.
- Acosta et al., 2016. Coenzyme Q biosynthesis in health and disease.
- Mantle et al., 2023. Primary Coenzyme Q10 Deficiency: An Update.
- Guerra & Pagliarini, 2024. Coenzyme Q biochemistry and biosynthesis.