Overview
Multiple mitochondrial dysfunctions syndrome type 5 (MMDS5) is a very rare and serious inherited condition that affects the mitochondria — the tiny structures inside your cells that produce energy. When the mitochondria do not work properly, the body cannot make enough energy to keep organs and tissues functioning normally. This especially harms organs that need a lot of energy, like the brain, heart, muscles, and liver. MMDS5 is caused by changes (mutations) in the ISCA1 gene, which plays an important role in helping mitochondria build certain proteins that are essential for energy production. Without these proteins working correctly, the mitochondria break down and cells begin to fail. The condition typically appears in early infancy and causes a wide range of serious problems. Key symptoms include severe developmental delay, loss of previously learned skills (regression), muscle weakness, problems with movement and coordination, seizures, and abnormalities seen on brain scans. The heart and liver may also be affected. There is currently no cure for MMDS5, and treatment focuses on managing symptoms and supporting quality of life. This condition is sometimes referred to as ISCA1-related mitochondrial disease.
Also known as:
Key symptoms:
Severe delay in reaching developmental milestones such as sitting, standing, or talkingLoss of skills the child had already learned (developmental regression)Muscle weakness and poor muscle tone (floppiness)Difficulty with movement and coordinationSeizuresAbnormal brain changes visible on MRI scans (leukoencephalopathy)Breathing difficultiesFeeding problems and poor weight gainLiver problemsHeart muscle disease (cardiomyopathy)High levels of lactic acid in the blood (lactic acidosis)Abnormal eye movements or vision problemsIrritability and reduced alertness
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Infantile
Begins in infancy, roughly 1 month to 2 years old
Treatments
No FDA-approved treatments are currently listed for Multiple mitochondrial dysfunctions syndrome type 5.
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Specialists
View all specialists →No specialists are currently listed for Multiple mitochondrial dysfunctions syndrome type 5.
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Multiple mitochondrial dysfunctions syndrome type 5.
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What specific changes were found in the ISCA1 gene, and what do they mean for my child's prognosis?,Should other family members, including siblings, be tested for carrier status?,What symptoms should prompt me to go to the emergency room immediately?,Is there an emergency protocol letter we should carry in case our child needs urgent hospital care?,Are there any clinical trials or research studies our child might be eligible for?,What supportive therapies — such as physiotherapy, speech therapy, or occupational therapy — would benefit my child most right now?,How do we access palliative care support, and when should we start that conversation?
Common questions about Multiple mitochondrial dysfunctions syndrome type 5
What is Multiple mitochondrial dysfunctions syndrome type 5?
Multiple mitochondrial dysfunctions syndrome type 5 (MMDS5) is a very rare and serious inherited condition that affects the mitochondria — the tiny structures inside your cells that produce energy. When the mitochondria do not work properly, the body cannot make enough energy to keep organs and tissues functioning normally. This especially harms organs that need a lot of energy, like the brain, heart, muscles, and liver. MMDS5 is caused by changes (mutations) in the ISCA1 gene, which plays an important role in helping mitochondria build certain proteins that are essential for energy productio
How is Multiple mitochondrial dysfunctions syndrome type 5 inherited?
Multiple mitochondrial dysfunctions syndrome type 5 follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Multiple mitochondrial dysfunctions syndrome type 5 typically begin?
Typical onset of Multiple mitochondrial dysfunctions syndrome type 5 is infantile. Age of onset can vary across affected individuals.