Unintended benefit of anabolic steroid use in hemophilia B leiden

Hemophilia B is an inherited bleeding disorder caused by mutations in the F9 gene, located on the X chromosome at position Xq27 [ 1 ]. In 1970, Veltkamp et al. described a rare form of hemophilia B, known as hemophilia B Leiden, distinguished by low levels of factor IX (FIX) in childhood and loss of the hemophilia phenotype following puberty [ 2, 3]. The mechanism of recovery in hemophilia B Leiden is controversial and is the subject of ongoing research. In the present case, we observed an unintended and dramatic rise in FIX levels after anabolic steroid use in a man with hemophilia B Leiden. This case lends additional support to the hypothesis that it is androgen that drives the increase in FIX expression in hemophilia B Leiden. We report the case of a 29-year-old man with mild hemophilia B who presented to the emergency department with an acute painful left quadriceps swelling. There was no preceding history of trauma. He was afebrile, with a mild leukocytosis of 17.1 × 109/L. Hemophilia B had been diagnosed at 13 months of age following bleeding complications associated with circumcision. The baseline FIX level was 12 IU/dL at diagnosis. He had sustained numerous provoked bleeding episodes during childhood requiring treatment with FIX concentrate. In the emergency department, he was treated with 1,800 units (20 IU/kg) of human plasma-derived FIX concentrate. The following day, his FIX level was 80 IU/dL, but his signs and symptoms had not improved. During that visit, he disclosed that he had been self-injecting the anabolic steroid stanozolol for the purpose of bodybuilding. A blood culture was positive for Staphylococcus aureus. He was admitted to hospital for intravenous antibiotics and drainage of a large abscess in the quadriceps muscle. He was advised to discontinue the use of stanozolol. The half-life of plasma derived FIX, in this case Immunine® VH (Baxter Corporation), is approximately 17 h; therefore, we would expect the effect of one dose of FIX to be gone within a few days. Without any further factor replacement, 7 and 8 days later, his FIX levels were 108 IU/dL and 104 IU/dL, respectively, and 1 month after hospitalization, his FIX level was 61 IU/dL. In the absence of anabolic steroids, the FIX level was 24 IU/dL 1 year later, and 2 years after his hospital admission it was 36 IU/dL, a level threefold higher than his childhood baseline (Fig. 1). Genotyping of the F9 gene revealed a G > A transition at nucleotide-6 within the Leiden-specific region (Fig. 2), consistent with a diagnosis of hemophilia B Leiden. Graph showing the subjects FIX levels throughout his life. The underlined portion denotes the period of use of stanozolol. Arrows indicate doses of plasma-derived FIX concentrate administration. Schematic diagram of F9 gene showing transcription factor-binding sites. Prior to puberty the F9 gene is dependent on binding of HNF-4 and C/EBP. Following puberty, the ARE, ASE, and AIE play a role in the transcription of F9. Mutations within the promoter region of the F9 gene are associated with the hemophilia B Leiden phenotype. ASE, age-related stability element; DBP, D site binding protein; HNF-4, hepatic nuclear factor-4; ARE, androgen response element; UKP-6, unknown protein; C/EBP, CCAATT enhancer-binding protein; AIE, age-related increase element. The F9 gene spans more than 34 kilobases of DNA and contains eight exons [ 1, 4]. More than 1,000 mutations within the F9 gene have been described [5] with the majority being point mutations. Patients with hemophilia B Leiden have mutations in the promoter region of the F9 gene between the nucleotides −34 and +19 (Fig. 2) [5]. This region is known as the Leiden-specific region. Located within this region are binding sites for liver-enriched transcription factors such as CCAAT enhancer-binding protein (C/EBP), located downstream of the transcription start site, and hepatocyte nuclear factor-4 (HNF-4), located upstream of the start site [4, 5]. Prior to puberty, transcriptional control of the F9 gene is dependent on binding of transcription factors (C/EBP and HNF-4) to the F9 promoter [5]. The mechanism of recovery in hemophilia B Leiden is controversial and is the subject of ongoing research. Two mechanisms have been proposed to play a role. Steroid hormones present during puberty may play an important role in expression of the F9 gene in hemophilia B Leiden acting via the androgen-response element (ARE) located within the F9 promoter. Individuals with mutations disrupting the ARE, such as hemophilia B Brandenburg (G > C mutation at −26 position), fail to improve after puberty, supporting the role of androgen in the recovery mechanism [6]. To further support this proposed mechanism, administration of exogenous anabolic steroids and testosterone to prepubertal boys with hemophilia B Leiden can raise FIX levels sufficient to prevent hemorrhage [7]. A second recovery mechanism that has been proposed involves the age-related stability element (ASE) upstream of the promoter region of F9, and the age-related increase element (AIE) located in the 3′-untranslated region [ 8, 9]. In an elegant study using transgenic mice with the T-20A hemophilia B Leiden mutation, Kurachi [8] showed the disruption of either the ASE or AIE interferes with postpubertal recovery. In this model, pubertal recovery of FIX expression is mediated by growth hormone signaling via the ASE. In the present case, we observed an unintended and dramatic rise in FIX levels after anabolic steroid use in a man with hemophilia B Leiden. This case demonstrated a dose-response effect, with a further rise in FIX beyond the postpubertal recovery that accompanied exposure to pharmacologic concentrations of androgen. To our knowledge, this is the first case to conclusively demonstrate that the exogenous administration of androgen in the postpubertal period can substantially raise FIX levels. This case lends additional support to the hypothesis that it is androgen that drives the increase in FIX expression in hemophilia B Leiden. Emily K. Rimmer* , Matthew D. Seftel* , Sara J. Israels §, Donald S. Houston* , * Department of Internal Medicine, University of Manitoba, Winnipeg, Canada, Department of Haematology and Medical Oncology, CancerCare Manitoba, Winnipeg, Canada, Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Canada, § Department of Pediatric Oncology/Haematology, CancerCare Manitoba, Winnipeg, Canada.

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