Mutation analysis of chromosome 19 calmodulin (CALM3) gene in Alzheimer's disease patients.

The calcium buffering capacity of lymphoblasts from patients suffering of late onset Alzheimer's disease (AD) has been reported to be diminished. Calmodulin is a calcium binding protein codified by three genes, one of them (CALM3) maps to chromosome 19, nearby a gene, apoE, associated with late onset AD. In this study we screened for structural changes in the CALM3 gene from AD patients by PCR-SSCP analysis. We observed several point mutations in the intronic flanking regions of exons 3 and 4 of CALM 3 gene. However, we failed to detect any structural changes in the regions encoding the calcium binding domains of this gene. Similar results were obtained by RT-PCR analysis of CALM3 transcripts from AD patients carrying apoE epsilon4 allele. It is concluded that structural alterations in the CALM3 gene are not associated with the altered Ca2+ homeostasis shown by lymphoblasts from these patients.