CAPILLARY ELECTROPHORESIS OF POLYMERASE CHAIN REACTION-AMPLIFIED PRODUCTS IN POLYMER NETWORKS - THE CASE OF KENNEDYS DISEASE

In Kennedy disease (an X-linked motoneuronal disorder associated with an increase in the number of (CAG)(n) triplet repeats in the first exo n of the Androgen receptor gene; about twice as many as in normal cond itions), polymerase chain reaction-amplified genic products exhibit tw o DNA fragments in the heterozygous female carriers, one with a range between 468 and 495 bp in the normal polymorphic population and a frag ment corresponding to the pathological state that reaches 573 bp. Thes e fragments are easily separated by gel-slab electrophoresis and detec ted by intercalating dye staining (ethidium bromide). As an alternativ e procedure, capillary zone electrophoresis in polymer networks, consi sting of 8% polyacryloylaminoethoxyethanol at 0% cross-linker, offers a simple procedure for separation and on-line detection via UV absorba nce at 254 nm, thus avoiding additional staining steps. The capillary column can be repeatedly used for up to 80-100 times and the electroph erogram is stored on a magnetic support. Easy comparison among differe nt runs is obtained by aligning all tracings to an internal standard o f a 650 bp fragment added as a marker.