Complete or almost complete loss of LPL function due to biallelic (homozygous or compound heterozygous) LPL variants causes autosomal recessive familial chylomicronemia syndrome (FCS; also known as type I hyperlipoproteinemia or LPL deficiency), which is characterized by extremely high plasma TG levels (> 10 mmol/L (880 mg/dL)) [5]. This evidence concerns the gene LPL and familial lipoprotein lipase deficiency.