What Your Test Results Mean:

Carriers typically show no symptoms of primary carnitine deficiency; however, carriers are at an increased risk of having a child with primary carnitine deficiency. Risk for the current or future pregnancies is dependent on your partner’s carrier status. Carrier testing of your partner is recommended in addition to consultation with a genetic counselor.

Disease Explained:

Primary carnitine deficiency is an inherited metabolic disorder that impairs the body’s uptake of carnitine, a molecule necessary for converting lipids into metabolic energy. Signs and symptoms of primary carnitine deficiency typically appear during infancy or early childhood and can include severe brain dysfunction, a weakened and enlarged heart, confusion, vomiting, muscle weakness, and low blood sugar. The severity of this condition varies among affected individuals, and can usually be effectively treated with an oral carnitine supplement, especially when diagnosed in a timely manner. While this disease is serious and even fatal without treatment, an affected individual who takes regular supplements can typically live a normal, healthy life. Management is typically overseen by a group of metabolic specialists.

How the Genetics Works:

Primary carnitine deficiency is an autosomal recessive disorder caused by pathogenic variants in the SLC22A5 gene. In general, individuals have two copies of the SLC22A5 gene. Carriers of primary carnitine deficiency have a single variant in one copy of the SLC22A5 gene while individuals with primary carnitine deficiency have variants in both copies of their genes, one inherited from each parent. Risk for two carriers to have a child with the disorder is 25%.