Prealbumin is a serum protein which plays an important role in plasma transport of retinol and thyroxine. The accumulation of a variant prealbumin is associated with a hereditary disorder, familial amyloidotic polyneuropathy (FAP). In situ hybridization with a mouse prealbumin gene cDNA probe was carried out in mouse fibroblasts. Analysis of 114 R-banded metaphases showed that 13 % of the total grains were located on chromosome 4 and 46% of the grains on this chromosome were in the region C6–D1. Linkage and syntenic group analysis showed that the prealbumin gene {Ttr) is located between two syntenic groups on mouse chromosome 4, which corresponded to two syntenic groups present on human chromosomes 1 and