Regional and cellular specificity of the expression of TPRD, the tetratricopeptide Down syndrome gene, during human embryonic development

The TPRD gene (tetratricopeptide (TPR) containing Down syndrome gene) is on e of the candidate genes in the Down syndrome chromosomal region-1. Duplica tion of this gene may be the cause of major phenotypic features of Down syn drome. Here we show that the TPRD expression is developmentally regulated d uring human embryogenesis. At the earliest stages of development (Camegie 8 -12) TPRD expression is ubiquitous. At later developmental stages (Carnegie stages 14, 16 and 18), it becomes restricted to the nervous system, as is the case for the mtprd gene during mouse development. We extended our analy sis of TPRD expression during fetal development of the human nervous system (13, 22 and 24 weeks). A new oblique illumination technique was used to co mpare signal intensity and cell density. Some regions of the nervous system such as the external cortical layers of the brain, and the inner neuroblas tic layer of the eye, strongly express the TPRD gene. (C) 2000 Elsevier Sci ence Ireland Ltd. All rights reserved.