Systemic primary carnitine deficiency

Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD's weight loss doctor NYC
Philadelphia GLP-1 weight loss and GLP-1 clinic NYC

Systemic primary carnitine deficiency
Carnitine structure
Synonyms	Primary carnitine deficiency, Carnitine uptake defect
Pronounce
Specialty	Genetics, Metabolism
Symptoms	Hypoglycemia, Cardiomyopathy, Muscle weakness, Fatigue
Complications	N/A
Onset	Infancy or early childhood
Duration	Chronic
Types	N/A
Causes	Genetic mutation in the SLC22A5 gene
Risks
Diagnosis	Blood test, Genetic testing
Differential diagnosis	Secondary carnitine deficiency, Fatty acid oxidation disorders
Prevention
Treatment	Carnitine supplementation
Medication
Prognosis	Good with treatment
Frequency	1 in 40,000 to 1 in 120,000
Deaths	Rare with treatment

Systemic Primary Carnitine Deficiency (SPCD), also known as Carnitine Uptake Defect or Carnitine Transporter Deficiency, is a rare genetic disorder that affects the body's ability to transport carnitine, a substance essential for the oxidation of long-chain fatty acids. This condition leads to a variety of symptoms, primarily affecting the muscles and heart, and can result in serious complications if not treated promptly.

Causes

SPCD is caused by mutations in the SLC22A5 gene, which encodes the organic cation transporter type 2 (OCTN2), responsible for the uptake of carnitine into cells. Without functional OCTN2, carnitine cannot be properly absorbed from the diet or conserved by the kidneys, leading to a systemic deficiency.

Symptoms

Symptoms of SPCD can vary widely among affected individuals but typically include muscle weakness, hypoglycemia (low blood sugar), cardiomyopathy (disease of the heart muscle), and hepatic encephalopathy (brain dysfunction caused by liver disease). Symptoms can appear anytime from infancy to adulthood, with some individuals remaining asymptomatic.

Diagnosis

Diagnosis of SPCD involves a combination of clinical evaluation, biochemical tests showing low plasma carnitine levels, and genetic testing confirming mutations in the SLC22A5 gene. Early diagnosis and treatment are crucial to prevent serious complications.

Treatment

The primary treatment for SPCD is oral L-carnitine supplementation, which can significantly improve symptoms and prevent metabolic crises. Patients may also require dietary modifications and management of symptoms related to complications.

Prognosis

With early diagnosis and appropriate treatment, individuals with SPCD can lead normal, healthy lives. However, untreated SPCD can result in severe metabolic crises, irreversible organ damage, and potentially fatal outcomes.