Analysis of a variable number of tandem repeats in a heart disease gene by capillary electrophoresis with laser-induced fluorescence detector.

Capillary electrophoresis with laser-induced fluorescence detector (CE-LIF) was successfully applied to the analysis of the variable number of tandem repeats (VNTR) in a human apolipoprotein B gene (APOB). Apolipoprotein B VNTR alleles containing more than 35 repeat units are a significant risk factor for heart disease. Thus, we developed a method for accurately determining the number of repeat units (16 bp) in the VNTR using capillary electrophoresis. The CE-LIF technique gave excellent resolution of APOB alleles differing by 2 or 4 repeat units over the range 600 to 1000 bp. The recommended conditions for the analysis of APOB VNTR loci by CE-LIF are as follows: effective length of capillary (100 microns i.d., 360 microns o.d.), 50 cm; running buffer, 50 mM Tris-borate 0.5% methylcellulose and 0.1 microM fluorescent dye YO-PRO-1; electric field, 150 V/cm.