APOC2 and hyperinsulinemic hypoglycemia, familial, 4: It was suggested that Schnauzer hyperlipidemia could be due to APOC2 deficiency, however Xenoulis et al. [27] have not found coding variants in the APOC2 gene and concluded that APOC2 hereditary deficiency is unlikely to be a major cause for primary hyperlipidemia in this breed.