Abstract Disclosure: M.F. Salazar Zelaya: None. J.D. Sibaja Jiménez: None. Background : Hypertriglyceridemia is a common medical scenario in daily practice, causing a variety of symptoms including recurrent episodes of acute pancreatits, which can be severe. Multiple genetic variants can lead to different spectrums of the disease. CLINICAL CASE: A 32 year old male police officer presented to our Endocrinology Outpatient Clinic with a history of long standing hypertriglyceridemia and six previous episodes of acute pancreatits, two in the last twelve months. Familiy history was negative for lipid disorders. The patient had adecuate adherence to diet and exercise as well to prescribed medications, which included Fenofibrate 250 mgs/day and Rosuvastatin 40 mgs/day. The patient denied consumption of alcoholic beverages. Recent abdominal ultrasound was reported without abnormalities. His lipid panel reported elevated triglycerides at 5831 mg/dl (n<150 mg/dl), Total Cholesterol normal at 147 (n<200 mg/dl), low HDL levels at 12 mg/dl (range 12-92 mg/dl) and direct LDL Cholesterol at 120 mg/dl. His TSH value was normal at 1.02 uUI/mL (range 0.55-4.78 uUI/mL). Creatinine level was normal at 0.81 mg/dl (range 0.7-1.3 mg/dl). Liver function tests were normal with AST level at 25 IU/L (range 13-39 IU/L) ALT levels at 22 IU/L (range 7-52 IU/L) and alcaline phosphatase at 62 IU/L (range 34-104 IU/L).His fasting glucose level were normal at 82 mg/dl (n<100 mg/dl). Due to a high Familial Chylomicronemia Syndrome clinical score (13 points) we proceeded with genetic analysis of this patient. Next Generation Sequencing for genes related with chylomicronemia (APOA5, APOC2, GPIHBP1,LMFI, LPL) was performed to determine gene sequence plus copy number variation.Two heterocigote variants were reported, both in the LPL gene. The first one: LPL (NM 000237.3) c.644>A;p.Gly215Glu heterozygous is a missense variant already reported in the literature, registered in ClinVar (ID 1522) and the Leiden Open Variation Database. This variant is classified as pathogenic according to criteria PS3, PM1, PP3, PP5 of the American College of Medical Genetics and Genomics. The second one: LPL (nm 000237.3): c.383C>A;p.Thr128Asn;heterozygous is also a missense variant which to the extent of our knowledge has previously been reported only once in the literature: ClinVar (ID 1520537). This variant is classified currently as of unknown clinical significance according to PM2 criteria. There is however and entry reported (PMID: 8778602) of another variant affecting the same codon (p.Thr128AIa) that is associated to chylomicronemia syndrome. Conclusion: In cases of severe hypertriglyceridemia, suspicion and determination of gene variants are of great importance nowadays as they could eventually guide treatment, given the availability in some countries (and currently pending FDA approval) of new pharmacological therapies such as apo C-III inhibitors. Presentation: 6/2/2024