title: Heterogeneity of the factor IX locus in nine hemophilia B inhibitor patients.
abstract: DNA from nine hemophilia B patients who produce anti-factor IX inhibitors (antibodies), including two brothers, was analyzed by the Southern blotting method and hybridization with factor IX cDNA, intragenomic, and 3'-flanking probes. Two inhibitor patients were shown to have total deletions of the factor IX gene. Two other inhibitor patients, the brothers, were shown to have a presumably identical complex rearrangement of the factor IX gene involving two separate deletions. The first deletion is of approximately 5.0 kb and removes exon e. The second deletion is between 9 and 29 kb and removes exons g and h but leaves exon f intact. An abnormal Taq I fragment at one end of the deletion junctions acted as a marker for the inheritance of hemophilia B in the patients' family. Five other inhibitor patients have a structurally intact factor IX gene as detected by this method. Our studies indicate that whereas large structural factor IX gene defects predispose hemophilia B patients to developing an anti-factor IX inhibitor, the development of an inhibitor can be associated with other defects of the factor IX gene.
mesh_terms: D004247:DNA / Q000235:genetics*; D004262:DNA Restriction Enzymes; D015252:Deoxyribonucleases, Type II Site-Specific; D005091:Exons; D005164:Factor IX / Q000235:genetics*; D002836:Hemophilia B / Q000235:genetics*; D006801:Humans; D008297:Male; D009154:Mutation; D009693:Nucleic Acid Hybridization; D011401:Promoter Regions, Genetic
chemical_list: D005164:Factor IX; D004247:DNA; D004262:DNA Restriction Enzymes; D015252:Deoxyribonucleases, Type II Site-Specific; C027046:TCGA-specific type II deoxyribonucleases