How LC-FAOD happens

Woman who typifies a caregiver with a child who typifies a person with LC-FAOD



In LC-FAOD, children inherit defective genes that control metabolism. (Metabolism is chemical processes that occur within a living cell or organism and are necessary for the maintenance of life.) To inherit LC-FAOD, both parents must be carriers. Each child inherits one copy of the affected gene from each parent.

With each pregnancy, parents have a:

  • 25% chance of having an affected child with two affected copies of the gene (left)
  • 50% chance of having an unaffected child who is also a carrier (middle)
  • 25% chance of having an unaffected child with two unaffected copies of the gene (right)

Autosomal recessive disorder inheritance graphic

LC-FAOD Disrupt Metabolism

To help you understand the complicated metabolic system, it helps to compare its function to an object you are probably quite familiar with: your smartphone.

In unaffected metabolism
the body has access to 2 sources of energy, similar to a smartphone.

The body can exert energy and/or fast for a prolonged period by drawing on reserved energy to keep the body powered.


Immediate energy functions like electricity from a wall outlet that:

  • Directly powers a smartphone
  • Charges its battery

Eating proteins, carbohydrates, and fats:

  • Provides direct source of immediate energy
  • “Charges” the body’s battery by converting these nutrients, including LCFAs, into reserve energy


Reserve energy functions like an internal battery when the separate direct power source is no longer available

Reserve energy helps power the body during periods of fasting (including sleep) or physical stress (illness or exercise)

the body has a faulty battery because it cannot rely on LCFAs to help it stay “charged”

When the body can’t supply enough energy to meet its need, people may develop chronic symptoms or experience acute episodes.


A faulty smartphone battery drains faster, requiring you to plug into the wall outlet more frequently

Eating proteins, carbohydrates, and fats:

  • Provides direct source of immediate, but not being able to use LCFAs leads to lower energy levels
  • Can “charge” the body’s battery (reserve energy), but the body can’t use the stored LCFAs for energy


Without a fully charged battery, a smartphone will begin powering down faster than normal when it’s unplugged from a direct power source

Since the body’s battery (reserve energy) can’t use LCFAs to stay fully charged, the body may not have enough energy during prolonged periods of fasting or physical stress

Have more questions about LC-FAOD?

Will my physician know what LC-FAOD are and how to treat them? What is the risk for other family members or future children? Find answers to these questions and more in the FAQs section.

Medical History

Keeping an up-to-date medical history and providing copies to your healthcare team can help make the most of your office visits.