Trifunctional Protein Deficiency (TFP)



Trifunctional protein deficiency (TFP) is a condition in which the body is unable to break down certain fats. Individuals affected by TFP are unable to convert some of the fats they eat into energy the body needs to function. Instead, too many unused fatty acids build up in the body. Detecting the condition early and beginning treatment can prevent some of the severe outcomes of TFP.  There are three distinct forms of trifunctional protein deficiency based on the age of onset — early, childhood, and mild. Babies with early TFP start showing signs of the condition between birth and age 2, while individuals with childhood TFP show signs after infancy. Mild TFP is very uncommon. Signs of early TFP include poor appetite, sleeping longer or more often, tiredness, weak muscle tone (called hypotonia), fever, vomiting, diarrhea, low blood sugar (hypoglycemia), irritability, behavior changes, no reflexes or pain responses, and developmental delays. Many of these signs may occur when a baby eats foods that his or her body cannot break down. Symptoms can be triggered by long periods of time without eating, illnesses, and infections.

Condition Type:

Core Conditions


The exact number of individuals with trifunctional protein deficiency (TFP) is unknown.

More Information for Parents:
Also known as:
  • Trifunctional protein deficiency
  • Trifunctional enzyme deficiency
  • Mitochondrial trifunctional protein deficiency
  • MTP deficiency
  • Type 2 trifunctional protein deficiency
  • TPA deficiency

Core Conditions