The human dynactin 1 gene (DCTN1) is positioned on chromosome 2p13, the candidate region for various diseases including Alstrom syndrome, limb-girdle muscle dystrophy, and Miyoshi myopathy. Here, we report the exon-intron structure of DCTN1 along with characterization of the 5' upstream sequence and alternative splice variants previously identified by Tokito et al. (1996), Mol. Biol. Cell 7: 1167-1180). Knowledge of the genomic structure of DCTN1allowed us to design intronic primers necessary for analyzing mutations in families segregating for diseases linked to this gene. These primers were tested on a French Acadian kindred segregating for Alstrom syndrome. No mutations were observed within the coding region of DCTN1 in this family. However, the intronic primers should allow for the rapid amplification of the coding region for mutational analysis of additional Alstrom families and other diseases tightly linked to the DCTN1locus on chromosome 2p13.