First, p.Ile221Thr homozygosity was found in a patient with LPL deficiency (patient presented at the age of 4 years with a history of hepatosplenomegaly and abdominal pain; plasma lipid analysis revealed chylomicronemia with TG levels in excess of 30 mmol/L; plasma LPL activity in this patient was undetectable) [51]. Here, LPL is linked to hyperinsulinemic hypoglycemia, familial, 4.