SUBTYPING ANALYSIS OF FANCONI-ANEMIA BY IMMUNOBLOTTING AND RETROVIRALGENE-TRANSFER

Fanconi anemia (FA) is an autosomal recessive cancer susceptibility sy ndrome with at least eight complementation groups (A-H). Two of the FA genes (FAA and FAG) have been cloned, and mutations in these genes ac count for approximately 80% of FA patients. subtyping of FA patients i s an important first step toward identifying candidates for FA gene th erapy. In the current study, we analyzed a reference group of 26 FA pa tients of known subtype. Most of the patients (18/26) were confirmed a s either type A or type C by immunoblot analysis with anti-FAA and ant i-FAG antisera. In order to resolve the subtype of the remaining patie nts, we generated retroviral constructs expressing FAA and FAC for tra nsduction of FA cell lines (pMMP-FAA and pMMP-FAC). The pMMP-FAA const ruct specifically complemented the abnormal phenotype of cell lines fr om FA-A patients, while pMMP-FAC complemented FA-C cells. In summary, the combination of immunoblot analysis and retroviral-mediated phenoty pic correction of FA cells allows a rapid method of FA subtyping.