Barth syndrome is a rare genetic condition that can weaken the heart and muscles, affect growth and make it harder to fight infections. It disrupts the work of mitochondria, the tiny structures inside cells that help turn food into usable energy. Its effects vary from person to person. MedlinePlus Genetics

If you or someone in your family has been diagnosed, you may be trying to understand what happens next: which health problems need attention, how daily life might change and what treatments can help. This page brings those questions together, with explanations of the research and links to organizations that support people living with Barth syndrome.

What causes Barth syndrome, and who can inherit it?

Barth syndrome is caused by a change in a gene called TAFAZZIN, previously called TAZ. Genes carry instructions that cells use to do their work. This gene provides instructions for making tafazzin, a protein that helps maintain cardiolipin. Cardiolipin is a fatty substance that supports the inner membrane, or lining, of mitochondria. When that process is disrupted, cells can struggle to produce energy normally. The heart and muscles are particularly vulnerable because they need so much energy. MedlinePlus Genetics

Why does it mainly affect boys and men?

TAFAZZIN is on the X chromosome, one of the packages of genetic information inside cells. Boys and men usually have one X chromosome, so a disease-causing change in their only copy of this gene can cause Barth syndrome. Girls and women usually have two X chromosomes. A working copy generally protects them, although rare cases in females have been reported.

A woman who carries the gene change has a 50% chance of passing it on in each pregnancy. Sons who inherit it are affected; daughters who inherit it are usually carriers without symptoms. An affected father passes the change to all his daughters and none of his sons.

Sometimes the gene change is new, so there may be no known family history. A genetic counselor can explain what a test result means for relatives and future pregnancies. Inheriting or passing on a gene change is not anyone’s fault. GeneReviews

What are the symptoms of Barth syndrome?

Symptoms differ between people and can change over time. Common problems include:

Heart muscle weakness, called cardiomyopathy, which can make pumping blood harder.
Muscle weakness and fatigue, which can delay movement milestones and limit physical activity.
Low levels of infection-fighting white blood cells, called neutropenia, which increase infection risk.
Slow growth, particularly during childhood.

Not everyone has all these features. MedlinePlus Genetics

Feeding difficulties and poor weight gain may also occur, especially early in life. Some people develop abnormal heart rhythms, called arrhythmias. GeneReviews

A symptom list alone cannot establish the diagnosis.

How is Barth syndrome diagnosed?

Clinicians look at symptoms, family history and test results together. Genetic testing can identify a disease-causing change in the TAFAZZIN gene. A specialist laboratory test, where available, can also help confirm the diagnosis by measuring the balance between cardiolipin and a related substance. You may see this called the MLCL:CL ratio on a report.

Not every gene change gives a clear answer. A result described as a variant of uncertain significance means there is not enough evidence to know whether that change causes disease. By itself, it neither confirms nor rules out Barth syndrome.

Heart tests and blood counts help clinicians assess how the condition is affecting someone and plan care. A genetics specialist can explain which findings support the diagnosis and whether relatives should be offered testing. GeneReviews

What does Barth syndrome mean for daily life?

Accounts collected by the Barth Syndrome Foundation show how the condition can affect education, independence and family routines. The experiences below reflect what some families reported, rather than what everyone should expect. Foundation patient report

School and activities

A child may want to join in but have less stamina than classmates. Fatigue can be mistaken for a lack of effort, especially when the child looks well.

Support can include rest breaks, extra time to move between classrooms, help carrying books and adjustments to physical activities. The right arrangements depend on the child’s needs and should be worked out with the family, school and care team. The Foundation’s resources for educators offer a starting point.

Work, independence and family life

Adults may need to plan around fatigue, illness and appointments. Some people in the Foundation’s patient report described reducing work hours or struggling to keep a predictable schedule. Families also spoke about the time and financial pressures of caregiving. Foundation patient report

Useful questions to bring to the care team include:

Which activities need adjustments, and which can continue?
What should a school or employer understand about fatigue and changing capacity?
How should we prepare for the move from children’s services to adult care?

These conversations should include the person’s own priorities: time with friends, education, work, hobbies and increasing independence.

What do we know about Barth syndrome life expectancy?

There is no single life-expectancy figure that reliably describes everyone with Barth syndrome. The condition can be life-threatening, particularly in early childhood, but some people live well into adulthood. GeneReviews describes adults in their 50s and reports individuals in their 60s. These examples show the range of possible outcomes; they are not an average or a promise. GeneReviews

A study published in May 2026 examined records of 502 people with confirmed or suspected Barth syndrome. It found that deaths were concentrated in the first few years of life, with heart failure a major cause. The researchers also found that periods with fewer deaths and hospitalizations did not mean symptoms had disappeared. Ongoing care remained important as people grew older. 2026 survival study

Why can statistics online be misleading?

Studies include people born in different decades, with different access to diagnosis and care. Some rely on information reported by families, and older adults are represented in small numbers. The 2026 study acknowledges these limitations, including uncertainty about survival later in life.

Also, transplant-free survival measures survival without a heart transplant. Someone who receives a transplant no longer counts in that group, even if they are alive. It is different from measuring survival alone. Study methods

For an individual or family, a more useful question is: “Given the current heart function, infection history and other health needs, what should we monitor and plan for?” A care team familiar with Barth syndrome can help put the research in the context of that person’s health.

How is Barth syndrome treated?

Care is tailored to the health problems each person has. It may involve heart specialists, blood specialists, genetics professionals, dietitians and therapists working together.

Treatment can include:

Heart care: medicines and monitoring for heart weakness or abnormal rhythms. Some people with severe heart failure may need a heart transplant.
Infection prevention and treatment: monitoring white blood cells and, when appropriate, medicines that help increase infection-fighting cells or reduce infections.
Feeding and growth support: help with nutrition and feeding difficulties.
Movement and development support: physical therapy and other services suited to the person’s abilities and needs.

There is currently no cure. Treatment and ongoing monitoring address particular complications and support daily functioning. GeneReviews

Where does Forzinity fit into care?

Forzinity is a prescription medicine containing elamipretide, also known by its research name SS-31. In the United States, it is approved to improve muscle strength in adults and children with Barth syndrome who weigh at least 30 kilograms, approximately 66 pounds.

That is a specific treatment goal. Forzinity does not replace care for heart problems, infections, nutrition or other needs. Its suitability should be discussed with the treating specialist.

Injection-site reactions are common, and serious allergic reactions have been reported. The prescribing information explains these risks and other precautions. Forzinity prescribing information

What does elamipretide research show?

The study supporting approval began with 12 people with Barth syndrome. During the randomized portion, participants received elamipretide and a placebo, an inactive comparison treatment, in separate periods. Elamipretide did not outperform placebo on the two main measures: walking distance and reported fatigue.

Ten participants entered a longer extension in which everyone received the medicine and knew they were taking it. This is called an open-label study. Improvements in the strength of muscles used to straighten the knee were observed during that extension. Those improvements had not been demonstrated during the randomized portion.

The findings supported FDA’s accelerated approval pathway. This allows earlier access for a serious condition while further research is required to confirm meaningful benefit. Because the extension was small and lacked a concurrent placebo group, it leaves uncertainty about how much of the observed change was caused by treatment. FDA trial summary

Does this approval apply to other SS-31 products?

No. The US approval applies to Forzinity as a specific prescription medicine. It does not establish that a vial sold online as SS-31 has the same composition, manufacturing controls or clinical evidence. Our SS-31 guide explains the names and product distinctions in more detail.

For readers outside the United States, FDA approval does not establish local authorization or availability. A local specialist or medicines regulator can help clarify the situation in your country.

Where can families find help with Barth syndrome?

If you are unsure where to begin, the Barth Syndrome Foundation’s Family Services team is a useful first contact. The organization provides information, guidance and emotional support, with opportunities to connect with other families. Contact Family Services.

Different resources can help with different needs:

If you need…	A place to start
A specialist medical evaluation	Kennedy Krieger Institute’s Barth Syndrome Clinic in Baltimore, USA. Its team evaluates and treats children and adults with confirmed or suspected Barth syndrome. Ask about referrals, appointment availability and costs before arranging travel.
Help in the United Kingdom	Barth Syndrome UK family support, with information and support for people affected by the condition and their families.
Resources in Canada	Barth Syndrome Canada, with family information and links to resources from the wider Barth community.
Help organizing care information	The Foundation’s Care Management Toolbox, with resources to support communication and care planning.

For families elsewhere, ask the Foundation about contacts or resources relevant to your country. Specialist services, referral requirements and financial support vary by location. These links are starting points, not guarantees of eligibility or access.

A useful next conversation

Consider asking your care team:

Who will coordinate care across the different specialists?
What changes should prompt a call, and what is our plan for urgent illness?
Where can we get help with school, work, emotional support or the practical costs of care?

You do not have to work out every question at once. A manageable first step is to connect with an experienced care team and a family-support organization that understands Barth syndrome.