Carnitine Uptake Defect (CUD)



Carnitine uptake defect (CUD) is an inherited condition in which the body cannot bring enough carnitine, a substance that helps the body convert energy from fats into the cells. Individuals affected by CUD are unable to break down certain fats, which can result in a build-up of unused fatty acids in the body. If untreated, CUD can cause brain damage or death. However, with early detection and treatment, individuals with CUD can often lead healthy lives. The first signs of CUD usually begin between birth and 3 years of age. Signs of CUD include sleeping longer or more often, tiredness, irritability, poor appetite, fever, vomiting, diarrhea, low blood sugar (hypoglycemia), behavior changes, confusion, and breathing troubles. Many of these signs may occur when a baby eats foods the body cannot break down. Symptoms can be triggered by long periods of time without eating, illnesses, and infections.

Condition Type:

Core Conditions


Carnitine uptake defect (CUD) affects approximately 1 in 100,000 babies in the United States.

More Information for Parents:
Also known as:
  • Primary carnitine deficiency
  • Systemic carnitine deficiency (SCD)
  • Carnitine uptake defect
  • Carnitine transporter deficiency
  • Carnitine transport defect
  • CUD
  • CTD
  • Maternal Carnitine Deficiency
  • Carnitine Uptake Defect

Core Conditions