E71.41

Clinical Causes: Genetic mutations in the SLC22A5 gene, which encodes the transporter responsible for absorbing and distributing carnitine throughout the body. Inheritance pattern is autosomal recessive, meaning a person must inherit two copies of the mutated gene, one from each parent, to manifest the disorder. Decreased ability to absorb dietary carnitine from the gut or to retain it in the body's tissues. Potential secondary factors, such as certain medications or illnesses, can exacerbate symptoms, but the primary cause remains genetic.

Key Symptoms: Muscle weakness and fatigue Hypotonia (reduced muscle tone), especially in infants Cardiac problems such as cardiomyopathy Low blood sugar levels (hypoglycemia) Delayed developmental milestones in children Episodes of weakness or cramps following physical activity Very low or absent serum carnitine levels on blood tests In some cases, symptoms may be mild or asymptomatic, especially in early stages.

Diagnosis Path: Blood tests to measure serum free and total carnitine levels, which are typically very low in affected individuals. Urinary carnitine tests to evaluate excretion levels. Genetic testing to identify mutations in the SLC22A5 gene. Additional assessments such as echocardiograms or muscle biopsies might be performed if cardiac or muscular symptoms are present. Newborn screening programs may detect elevated levels of certain metabolites indicative of the disorder.

Treatment Protocols: L-carnitine supplementation, often administered orally, is the primary treatment to replenish deficient levels. Regular monitoring of blood carnitine concentrations to adjust dosage. Dietary adjustments to ensure adequate intake of nutrients supporting energy metabolism. Management of cardiac issues if present, such as medications or other interventions as recommended by specialists. Lifestyle considerations, including avoiding prolonged fasting and maintaining a balanced diet, to prevent metabolic crises.