APOF and Smith-Lemli-Opitz syndrome: The second group contains variants of terms that appear rarely in PubMed, such as ‘Apo-F’ (14), ‘apolipoprotein c-3’ (4), ‘IDL I’ (1), ‘VLDL chol’ (34), ‘diabetis’ (37, instead of 270177 occurrences for ‘diabetes’), ‘free chol’ (0, instead of 2622 for ‘free cholesterol’), ‘hypolipoproteinaemia’ (5, “ae” spelling is rare), ‘insuline resistant’ (0, instead of 3912 for ‘insulin resistant’), ‘slo syndrome’ (36) and ‘sphingomyelinase deficiency disease’(0, MeSH synonym for ‘Niemann-Pick Disease’).