Some children with feeding problems requiring feeding tubes are eventually diagnosed with mitochondrial diseases. These conditions, which affect the energy production of cells, are not well understood by many doctors and diagnosis can be challenging. Children are frequently misdiagnosed for years. See the sidebar on Mitochondrial Disease Testing for more information.

Mitochondria are responsible for 90% of the energy that the body needs. When mitochondria fail to produce enough energy, cells and organs do not function. With mitochondrial disease, chronic failure to produce energy results in disease progression.

Mitochondrial disease often presents as dysmotility in children with feeding problems, meaning that food is not moving through the GI tract as it should.

What is Mitochondrial Disease?

  • Mitochondrial disease is a chronic, genetic disorder that occurs when the mitochondria of the cell fails to produce enough energy for cell or organ function.
  • The incidence is about 1:4000 individuals in the US. This is similar to the incidence of cystic fibrosis of Caucasian births in the U.S.
  • There are many forms of mitochondrial disease.
  • Mitochondrial disease is inherited in a number of different ways.
  • Mitochondrial disease presents very differently from individual to individual.
  • There may be one individual in a family or many individuals affected over a number of generations.

Source: MitoAction

How does Mitochondrial Disease affect the body?

The parts of the body that need the most energy, such as the heart, brain, muscles and lungs, are the most affected by mitochondrial disease. The affected individual may have strokes, seizures, gastrointestinal problems, (reflux, severe vomiting, constipation, diarrhea), swallowing difficulties, failure to thrive, blindness, deafness, heart and kidney problems, muscle failure, heat/cold intolerance, diabetes, lactic acidosis, immune system problems, and liver disease.

What symptoms could an undiagnosed individual exhibit?

The child or adult may have seizures, severe vomiting, failure to thrive, heat/cold intolerance, poor muscle tone, delayed achievement of milestones, severe diarrhea/constipation, feeding problems, unable to fight typical childhood infections or repeated infections and fevers without a known origin. A “red flag” for mitochondrial disease is when a child or adult has more than three organ systems with problems or when a “typical” disease exhibits atypical qualities.

Source: United Mitochondrial Disease Foundation

Think mitochondrial disease when three or more organ systems are involved!

UMDF has a comprehensive list of organ systems which can be involved in mitochondrial disease.

Mitochondrial Disease Testing

There are three primary methods of diagnosing mitochondrial disease, which are often combined for better accuracy: muscle biopsy, genetic testing, and clinical diagnosis.

A muscle biopsy takes a sample of muscle, which is then tested either immediately (preferred) or frozen and later tested. The health of the muscle is evaluated, and defects in the mitochondria can help diagnose the specific type of mitochondrial defect.

Genetic testing may consist of specific screening, such as DNA sequencing that is specially designed to look for mitochondrial abnormalities. Whole exome sequencing, in which the entire genome is evaluated, may also be valuable in some cases.

A clinical diagnosis may be made based on symptoms that affect multiple body systems, along with specific metabolic blood and urine tests, and other diagnostic tests related to the affected body systems.