Abstract 1962 Poster Session II, Sunday, 5/2 (poster 186)

A recent observation in the F1 generation of inbred, taurine-deficient cats provides evidence for the role of taurine deficiency in renal development. In these studies, taurine-deficient female cats were bred with taurine-deficient males. Fetal wastage was high, and the surviving F1 kits showed blindness, ataxia, cerebellar abnormalities, kyphosis, and peculiar facial features, as well as diminished renal size. Histologic examination of the kidneys showed ureteral dilatation, large glomeruli, proximal tubular flattening and abnormal differentiation of renal tubular epithelium, especially in the distal tubule, where taurine is found to be in high concentration by immuno-histochemical evaluation. With prolonged taurine deficiency (2 years) in these F1 cats, renal scarring, tubule disorganization, scarring and atrophy occur, as well as glomerulosclerosis. Renal size is also greatly diminished.

The gene for the taurine transporter has been cloned from different species and tissues. It has been assigned to the central region of mouse chromosome 6 and human chromosome 3p21-26, where a linkage group of genes is conserved between mouse and man. Mice treated with alanine, a taurine transport competitor, show taurine deficiency in vivo.

A remarkable similarity exists between human infants with deletion of bands p25-pter of chromosome 3 and the F1 generation of taurine-deficient kits. These children have a specific syndrome of craniofacial manifestations, prenatal growth delay, hypotonia, developmental retardation, cataracts and cleft palate. In addition, they have renal anomalies including renal hypoplasia, renal malposition (pelvic kidneys) and cortical cysts with increased interstitial connective tissue. Genitourinary anomalies also include small cortical cysts and bladder hypoplasia. The facial features of the taurine-deficient kit and the band p25-pter human infant show ptosis, telecanthus, a slight mongoloid slant, down-turned and low set ears, epicanthal folds and, in some cases, a cleft lip. Postaxial polydactaly has also been found in the feline and human conditions. Altered taurine transport may cause taurine deficiency in animals, including human.