In view of the importance of estrogens in the maintenance of the skeleton in men, we have carried out mutational analysis of all the exons of the estrogen-receptor-alpha (ER-alpha) gene in 64 men (36 patients with symptomatic vertebral crush fractures and 28 control subjects). Initial screening of the ER-alpha gene, carried out by single-strand conformation polymorphism analysis followed by sequencing, showed conservative mutations in exon 4 which resulted in a single base substitutions producing GGG-->GGC transition in codon 274. We also carried out polymorphic analysis of the ER-alpha gene at the PvuII restriction site in 82 men with a range of bone density measurements (53 with symptomatic vertebral fractures and 29 controls). The frequencies of PP, Pp, and pp genotypes were 20.7%, 48.8%, and 30.5%, respectively. The distribution of the alleles was similar in the patients with symptomatic vertebral crush fractures and male control subjects. There was no association between ER-alpha genotypes and bone mineral density or arthropometric parameters. This relatively small study suggests that mutations in the ER-alpha gene are unlikely to be a common cause of osteoporosis in men with vertebral fractures. Furthermore, polymorphic variation of the ER-alpha gene appears to have little effect on the pathogenesis of osteoporosis in men.