APOE and diabetes mellitus: No significant differences were found in the prevalence of APOE ε4 (22% vs 32%, p = 0.403) or the CN loss in intron 2 of SFMBT1 (9% vs 9%, p = 1.000) (Table 3), but diabetes was present in 3 out of the 4 probable fNPH patients that had CN loss in the SFMBT1 gene compared to none out of 2 of the non-iNPH relatives.