Molecular basis of the familial chylomicronemia syndrome in patients from the National Dyslipidemia Registry of the Spanish Atherosclerosis Society.

•We studied data from the Spanish Atherosclerosis Society Dyslipidemia Registry.•We diagnosed 26 patients with familial chylomicronemia syndrome.•We identified 5 novel mutations in LPL (2), GPIHBP1 (1), and APOA5 (2).•Twenty-three patients were homozygous for mutations in LPL (19) and GPIHBP1 (4).•Three patients heterozygous for mutations in LPL or APOA5 had LPL activity deficiency.