Zinc Deficiency-Like Syndrome in Fleckvieh Calves: Clinical and Pathological Findings and Differentiation from Bovine Hereditary Zinc Deficiency

Langenmayer, M.C.; Jung, S.; Majzoub-Altweck, M.; Trefz, F.M.; Seifert, C.; Knubben-Schweizer, G.; Fries, R.; Hermanns, W.; Gollnick, N.S.

The gene PLD4 encodes Phospholipase D4, which belongs to the PLD superfamily, comprising 6 members (PLD1-6) widely distributed in tissues of humans and animals. 33 PLD1 1 2 are well characterized phospholipid signaling enzymes, involved in cellular proliferation and vesicle trafficking. 5 Enzymes with PLD activity or phospholipase domains are further involved in keratinocyte metabolism or the keratinization process. [34] [35] [36] However, little is known about role and function of PLD4. Localized in the spleen and early microglia, a role in immunological pathways has been suggested. 4 Its enzymatic activity is still enigmatic and possible nonenzymatic functions are discussed. 33 There is considerable interspecies phenotypic variation between the few diseases and syndromes linked to PLD4 so far. Recent studies associated variants in PLD4 with systemic sclerosis and rheumatoid arthritis in the Japanese population. 6, 7, 37 Mice carrying a nonsense mutation in PLD4 manifest a phenotype with thin hair and small size that seems quite distinct from ZDL syndrome in calves. 38, 39 These substantial differences between the species highlight the importance of different models, which allow investigation of PLD4 functions and its position within metabolic pathways.