A Line 1 insertion in the Factor IX gene segregates with mild hemophilia B in dogs.
We undertook the biochemical and molecular characterization of hemophilia in a large pedigree of German wirehaired pointers. Males affected with hemophilia B had approximately 5% normal Factor IX coagulant activity and a proportional reduction of Factor IX protein concentration, indicative of a mild hemophilia B phenotype. Using Southern blot analyses and PCR amplification of genomic DNA, we discovered a large, 1.5-kb insertion in intron 5 of the Factor IX gene of an affected male. The insert consists of a 5' truncated canine Line-1 followed by an approximately 200-bp 3' poly (A) tract, flanked by a 15-bp direct repeat. The insert can be traced through at least five generations and segregates with the hemophilia B phenotype in this breed. This is the first description of a Factor IX mutation associated with mild hemophilia B in a non-human species and provides evidence for a recent Line-1 insertion event in the canine genome.
Brooks
Marjory B
MB
Department of Population Medicine and Diagnostic Sciences, Comparative Coagulation Section, College of Veterinary Medicine, Cornell University, Upper Tower Road, Ithaca, NY 14853, USA. mbb9@cornell.edu
Gu
Weikuan
W
Barnas
Jennifer L
JL
Ray
Jharna
J
Ray
Kunal
K
D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D017931:DNA Primers; D004283:Dog Diseases / Q000235:genetics*; D004285:Dogs; D005164:Factor IX / Q000235:genetics* / Q000378:metabolism; D005260:Female; D002836:Hemophilia B / Q000235:genetics / Q000662:veterinary*; D007438:Introns / Q000235:genetics; D020084:Long Interspersed Nucleotide Elements / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010375:Pedigree; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
D017931:DNA Primers; D005164:Factor IX