Patients with primary carnitine deficiency treated with L‐carnitine are alive and doing well—A 10‐year follow‐up in the Faroe Islands

Primary carnitine deficiency (PCD) can be lethal. Carnitine is essential for the transfer of long‐chain fatty acids across the inner mitochondrial membrane for β‐oxidation. The reported prevalence of PCD in the Faroe Islands of 1:300 is the highest in the world. The Faroese PCD patient cohort has been closely monitored and we now report results from a 10‐year follow‐up study of 139 PCD patients. Four patients have died of natural causes since diagnosis. There were no signs of cardiac complications related to PCD. 70.5% reported an effect of L‐carnitine treatment. 33.7% reported current symptoms with fatigue and low stamina being the most common. 65.1% had experienced side effects during L‐carnitine treatment. Most common side effects were fish odor, abdominal pain, and diarrhea. The overall mean L‐carnitine dosage was 66.3 mg/kg/day. Free p‐carnitine was similar between male and female patients on L‐carnitine—18.6 and 18.8 μmol/L, respectively. L‐carnitine supplementation seems to be a safe and effective treatment when suffering from PCD. PCD patients in the Faroe Islands are alive and doing well more than 10 years after diagnosis.