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Brenig B, Steingräber L, Shan S, Xu F, Hirschfeld M, Andag R, Spengeler M, Dietschi E, Mischke R, Leeb T. Christmas disease in a Hovawart family resembling human hemophilia B Leyden is caused by a single nucleotide deletion in a highly conserved transcription factor binding site of the F9 gene promoter. Haematologica 2019; 104:2307-2313. [PMID: 30846504 PMCID: PMC6821609 DOI: 10.3324/haematol.2018.215426] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 03/06/2019] [Indexed: 11/09/2022] Open
Abstract
Hemophilia B is a classical monogenic, X-chromosomal, recessively transmitted bleeding disorder caused by genetic variants within the coagulation factor IX gene (F9). Although hemophilia B has been described in dogs, it has not yet been reported in the Hovawart breed. Here we describe the identification of a Hovawart family transmitting typical signs of an X-linked bleeding disorder. Five males were reported to suffer from recurrent hemorrhagic episodes. A blood sample from one of these males with only 2% of the normal concentration of plasma factor IX together with samples from seven relatives were provided. Next-generation sequencing of the mother and grandmother revealed a single nucleotide deletion in the F9 promoter. Genotyping of the deletion in 1,298 dog specimens including 720 Hovawarts revealed that the mutant allele was only present in the aforementioned Hovawart family. The deletion is located 73 bp upstream of the F9 start codon in the conserved overlapping DNA binding sites of hepatocyte nuclear factor 4α (HNF-4α) and androgen receptor (AR). The deletion only abolished binding of HNF-4α, while AR binding was unaffected as demonstrated by electrophoretic mobility shift assay using human HNF-4α and AR with double-stranded DNA probes encompassing the mutant promoter region. Luciferase reporter assays using wildtype and mutated promoter fragment constructs transfected into Hep G2 cells showed a significant reduction in expression from the mutant promoter. The data provide evidence that the deletion in the Hovawart family caused a rare type of hemophilia B resembling human hemophilia B Leyden.
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Affiliation(s)
- Bertram Brenig
- University of Göttingen, Institute of Veterinary Medicine, Göttingen, Germany
| | - Lilith Steingräber
- University of Göttingen, Institute of Veterinary Medicine, Göttingen, Germany
| | - Shuwen Shan
- University of Göttingen, Institute of Veterinary Medicine, Göttingen, Germany
| | - Fangzheng Xu
- University of Göttingen, Institute of Veterinary Medicine, Göttingen, Germany
| | - Marc Hirschfeld
- University of Göttingen, Institute of Veterinary Medicine, Göttingen, Germany.,Department of Obstetrics and Gynecology, Freiburg University Medical Center, Freiburg, Germany
| | - Reiner Andag
- University Medical Center Göttingen, Institute for Clinical Chemistry, Göttingen, Germany
| | | | | | - Reinhard Mischke
- Small Animal Clinic, University of Veterinary Medicine Hannover Foundation, Hannover, Germany
| | - Tosso Leeb
- Institute of Genetics, University of Bern, Bern, Switzerland
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