There are a number of genes that have been linked to Alzheimers disease (AD). Since presence of the E4 allele of the apolipoprotein E (apo E) gene is thought to confer increased risk of AD, apo E genotyping is now routinely used for Alzheimers risk assessment in molecular diagnostic laboratories. Although a variety of methods have been reported, apo E genotyping usually involves restriction endonu- clease digestion of polymerase chain reaction (PCR)-amplified genomic DNA. This is a relatively simple technique, but interpretation of the patterns often is subjective and is complicated by incomplete DNA digestion, variable DNA load of the gels, and low sensitivity of detection techniques. We improved standardization of DNA load of the gels and increased the sensitivity of band detection by using SYBR Green instead of ethidium bromide staining. We made band detection more objective by developing a quantitative approach with image analysis. The density of various restriction bands was quantified relative to the largest restriction fragment and decision levels were established to distinguish true from partially digested fragments. Recently, a polymorphism of the human alpha2-macroglobulin gene was also iden-tified as a risk factor for AD. We developed a new, practicable method for the detection of a deletion polymorphism of this gene. This new method is based on a semi-automated PCR-single stranded polymorphism approach and we showed that it is as reliable as direct sequencing. In other studies, we continue studying the pathogenetic role of apolipoprotein(a) isoforms and alleles in patients with heart disease and in those with sytemic lupus erythematosus.
