Systemic primary carnitine deficiency

Gene : SLC22A5

What is systemic primary carnitine deficiency?

Systemic primary carnitine deficiency (CDSP) is an inherited disorder where the body is unable to use certain fats for energy. Symptoms typically start between three months and two years of age. During times of illness or fasting, children affected with CDSP can have episodes of low blood sugar, poor feeding, irritability, and weakness. These episodes could lead to coma and sudden death. Affected individuals often have weak muscles, including weak and enlarged heart muscles that lead to heart failure. The liver also often becomes enlarged. The severity of symptoms is quite variable. Some individuals may only experience muscle fatigue in adulthood and some may have no symptoms at all. Intellect is not affected by CDSP. Treatment with lifelong carnitine supplementation and avoiding long periods without food generally eliminate the risk for complications of CDSP. CDSP is caused by pathogenic variants in the SLC22A5 gene.

How is systemic primary carnitine deficiency inherited?

CDSP is inherited in an autosomal recessive manner. This type of inheritance requires the presence of two copies of a pathogenic variant for a person to have the genetic disease. Both parents must be carriers of a pathogenic variant in the gene in order to be at risk to have an affected child. The child must inherit a pathogenic variant from each carrier parent in order to be affected. There is a 1 in 4 chance that a baby will inherit two mutated copies of the gene and be affected when both parents are carriers.

What does it mean to be a carrier?

There are generally no signs or symptoms associated with being a carrier for CDSP. However, the risk to have a child affected with CDSP is increased. Testing of reproductive partners is recommended for carriers of CDSP.

How common is systemic primary carnitine deficiency?

CDSP is estimated to affect between 1 in 50,000-100,000 newborns in the United States. It is more common in Japan, where it affects 1 in 40,000 newborns.

Family References and Resources
Clinician References
What is Analyzed?
  • Full gene sequencing
Affected Systems





Carrier Rates
Detection Rate
Carrier Frequency
East Asian 99% 1 in 100
General Population 99% 1 in 132

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