APOE1 mutation in a patient with type III hyperlipoproteinaemia: detailed genetic analysis required

We present the case of a patient with clinical features of familial dysbetalipoproteinaemia (FD) including high levels of total cholesterol, hypertriglyceridaemia and the presence of palmar xanthomas. Whereas genotype analysis identified the APOE3E3 isoform, sequence analysis revealed the presence of one APOE1 allele due to a mutation, p.Lys164Glu, which leads to loss of function of apolipoprotein E (ApoE), a rare cause of dominant FD