States associated with insulin resistance, as overweight/obesity, type 2 diabetes mellitus (DM2), cardiovascular diseases (CVD), some cancers and neuropsychiatric diseases are characterized with a decrease of long-chain polyunsaturated fatty acids (LC-PUFA) levels. Amounts of LC-PUFA depend on the exogenous intake of their precursors [linoleic (LA) and α-linolenic acid (ALA)] and by rate of their metabolism, which is influenced by activities of enzymes, such as Δ6-desaturase (D6D, FADS2), D5D, FADS1, elongases (Elovl2, -5, 6).Altered activities of D5D/D6D were described in plenty of diseases, e.g. neuropsychiatric (depressive disorders, bipolar disorder, dementia), metabolic (obesity, metabolic syndrome, DM2) and cardiovascular diseases (arterial hypertension, coronary heart disease), inflammatory states and allergy (Crohns disease, atopic eczema) or some malignancies. Similar results were obtained in studies dealing with the associations between genotypes/haplotypes of FADS1/FADS2 and above mentioned diseases, or interactions of dietary intake of LA and ALA on one hand and of the polymorphisms of minor allels of FADS1/FADS2, usually characterized by lower activities, on the other hand.The decrease of the desaturases activities leads to decreased concentrations of products with concomitant increased concentrations of substrates. Associations of some SNP FADS with coronary heart disease, concentrations of plasma lipids, oxidative stress, glucose homeostasis, and inflammatory reaction, were described. Experimental studies on animal models and occurrence of rare diseases, associated with missing or with marked fall activities of D5D/D6D emphasized the significance of desaturases for healthy development of organism as well as for pathogenesis of some disease.
Keywords: cardiovascular and metabolic diseases.; delta-5-desaturase; delta-6-desaturase; genes FADS1/FADS2; inflammation; oxidative stress; polyunsaturated fatty acids.