Lamins A and C are products of alternate splicing of one transcript from a single gene. We have isolated a partial cDNA, cE1-2, whose 800-bp sequence is 99% identical to the 3' untranslated region of the lamin A/C gene. We report here the mapping of this gene and a closely related sequence to human chromosomes 1 and 10, more specifically, to 1q12.1-q23. The localization of cE1-2 hybridizing sequences to two different chromosomes suggests that one of these loci represents an as yet unknown member of the lamin gene family, either a pseudogene or an expressed gene.