Von Hippel-Lindau disease masquerading as autosomal dominant polycystic kidney disease

Co-occurrence of neurofibromatosis type 1 and optic nerve gliomas with autosomal dominant polycystic kidney disease type 2

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) and neurofibromatosis type 1 (NF1) are both autosomal dominant disorders with a high rate of novel mutations. However, the two disorders have distinct and well-delineated genetic, biochemical, and clinical findings. Only a few cases of coexistence of ADPKD and NF1 in a single individual have been reported, but the possible implications of this association are unknown.

METHODS

We report an ADPKD male belonging to a family of several affected members in three generations associated with NF1 and optic pathway gliomas. The clinical diagnosis of ADPKD and NF1 was performed by several image techniques.

RESULTS

Linkage analysis of ADPKD family was consistent to the PKD2 locus by a nonsense mutation, yielding a truncated polycystin-2 by means of next-generation sequencing. The diagnosis of NF1 was confirmed by mutational analysis of this gene showing a 4-bp deletion, resulting in a truncated neurofibromin, as well. The impact of this association was investigated by analyzing putative genetic interactions and by comparing the evolution of renal size and function in the proband with his older brother with ADPKD without NF1 and with ADPKD cohorts.

CONCLUSION

Despite the presence of both conditions there was not additive effect of NF1 and PKD2 in terms of the severity of tumor development and/or ADPKD progression.

Glioma in Patients with Autosomal-Dominant Polycystic Kidney Disease

BACKGROUND

Autosomal-dominant polycystic kidney disease (ADPKD) is an inherited systemic condition with a predominant feature of cyst formation in both kidneys. An association with intracranial glioma has not been described previously in ADPKD.

CASE DESCRIPTION

We report 2 cases of glioma in patients with ADPKD. One patient had a cystic lesion with contrast enhancement in the right temporal lobe as revealed by magnetic resonance imaging and an aneurysm in left sylvian fissure confirmed by computed tomography angiography. Subsequent histopathologic analysis of the resected enhancing lesion confirmed the diagnosis of glioblastoma (World Health Organization grade IV). The second patient was found to harbor a solid lesion in the right parietal lobe. This lesion also proved to be an astrocytoma (World Health Organization grade II).

CONCLUSIONS

These 2 independent cases of glioma suggest an unusual clinical manifestation of ADPKD. The potential association between ADPKD and glioma pathogenesis should be further explored.

Acquired Multiple Cysts of the Kidney in Neuroblastoma Survivors

Cystic kidney disease includes a wide range of hereditary, developmental, and acquired conditions of the kidneys. Some of the inherited causes of cystic kidney disease include autosomal dominant polycystic kidney diseases (caused by mutations in PKD1 or PKD2), autosomal recessive polycystic kidney disease, tuberous sclerosis complex, von Hippel-Lindau disease, oral-facial-digital syndrome type I, and Hadju-Cheney syndrome. Acquired cystic kidney disease has been reported in patients receiving long-term hemodialysis or peritoneal dialysis and in children after liver transplantation. Acute kidney injury can occur in patients with neuroblastoma, usually as a result of thrombotic microangiopathy associated with bone marrow transplantation. End-stage renal disease is described in long-term survivors. However, in this case report, we provide what is to our knowledge the first description of multiple kidney cysts in long-term survivors of stage IV neuroblastoma. None of the 7 patients we describe with neuroblastoma and multiple kidney cysts had a family history of autosomal dominant polycystic kidney disease. Also, all lacked stigmata of tuberous sclerosis complex, von Hippel-Lindau disease, or Hadju-Cheney syndrome. Two patients progressed to end-stage renal disease; in addition, one of them developed an oncocytoid renal cell carcinoma.

Polycystic kidney disease: the complexity of planar cell polarity and signaling during tissue regeneration and cyst formation

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is an inherited systemic disease with intrarenal cystogenesis as its primary characteristic. A variety of mouse models provided information on the requirement of loss of balanced polycystin levels for initiation of cyst formation, the role of proliferation in cystogenesis and the signaling pathways involved in cyst growth and expansion. Here we will review the involvement of different signaling pathways during renal development, renal epithelial regeneration and cyst formation in ADPKD, focusing on planar cell polarity (PCP) and oriented cell division (OCD). This will be discussed in context of the hypothesis that aberrant PCP signaling causes cyst formation. In addition, the role of the Hippo pathway, which was recently found to be involved in cyst growth and tissue regeneration, and well-known for regulating organ size control, will be reviewed. The fact that Hippo signaling is linked to PCP signaling makes the Hippo pathway a novel cascade in cystogenesis. The newly gained understanding of the complex signaling network involved in cystogenesis and disease progression, not only necessitates refining of the current hypothesis regarding initiation of cystogenesis, but also has implications for therapeutic intervention strategies. This article is part of a Special Issue entitled: Polycystic Kidney Disease.

Renal involvement in tuberous sclerosis complex and von Hippel-Lindau disease: shared disease mechanisms?

Tuberous sclerosis complex and von Hippel-Lindau disease are distinct autosomal dominant tumor suppressor syndromes that can exhibit similar renal phenotypes and seem to share some signaling pathway components. Similarities exist in the current clinical management of, and the newly identified potential therapeutic approaches for, these conditions. This Review summarizes the pathophysiologic and therapeutic overlap between tuberous sclerosis complex and von Hippel-Lindau disease and highlights the results of recent drug trials in these settings.

Hypoxia-inducible factors in the kidney

Tissue hypoxia not only occurs under pathological conditions but is also an important microenvironmental factor that is critical for normal embryonic development. Hypoxia-inducible factors HIF-1 and HIF-2 are oxygen-sensitive basic helix-loop-helix transcription factors, which regulate biological processes that facilitate both oxygen delivery and cellular adaptation to oxygen deprivation. HIFs consist of an oxygen-sensitive alpha-subunit, HIF-alpha, and a constitutively expressed beta-subunit, HIF-beta, and regulate the expression of genes that are involved in energy metabolism, angiogenesis, erythropoiesis and iron metabolism, cell proliferation, apoptosis, and other biological processes. Under conditions of normal Po(2), HIF-alpha is hydroxylated and targeted for rapid proteasomal degradation by the von Hippel-Lindau (VHL) E3-ubiquitin ligase. When cells experience hypoxia, HIF-alpha is stabilized and either dimerizes with HIF-beta in the nucleus to form transcriptionally active HIF, executing the canonical hypoxia response, or it physically interacts with unrelated proteins, thereby enabling convergence of HIF oxygen sensing with other signaling pathways. In the normal, fully developed kidney, HIF-1alpha is expressed in most cell types, whereas HIF-2alpha is mainly found in renal interstitial fibroblast-like cells and endothelial cells. This review summarizes some of the most recent advances in the HIF field and discusses their relevance to renal development, normal kidney function and disease.

Von Hippel-Lindau disease--a rare disease important to recognize

INTRODUCTION

Von Hippel-Lindau disease (VHL) is an autosomal dominant multisystemic cancer syndrome due to a mutation of the VHL tumor suppressor gene on chromosome 3, region p25-26, with an incidence of 1/36,000 in newborns. Patients are at risk of developing cerebellar, spinal and retinal hemangioblastoma, renal cell carcinoma, pheochromocytoma, pancreatic neuroendocrine tumors, pancreatic and renal cysts, and epididymal cystadenoma. The most common causes of death from VHL are metastases from renal cell carcinoma and neurological complications from cerebellar hemangioblastomas. Molecular analysis of the VHL gene is clinically available and indicated in patients with known or suspected VHL.

CASE REPORT

A 19-year-old woman was surgically treated for cerebellar hemangioblastoma in 1998 and for renal cell carcinoma of the right side in 2002. Familial VHL was subsequently diagnosed as the patient's mother was found to be affected with bilateral polycystic kidney disease with chronic renal failure as well as hemangioblastoma of the retina and medulla oblongata. The mother underwent surgery for bilateral renal cell carcinoma in 2003.

CONCLUSION

The multitude of VHL-associated tumors and intra-familial variability in clinical expressivity render early diagnosis of VHL difficult. We therefore shortly illustrate the spectrum of clinical phenotypes and the VHL screening and surveillance guidelines.

von Hippel-Lindau disease: recent advances and therapeutic perspectives

von Hippel-Lindau disease is a hereditary cancer syndrome predisposing carriers to the development of a panel of highly vascularized tumors such as central nervous system and retinal hemangioblastomas, endolymphatic sac tumors, clear-cell renal cell carcinomas, pheochromocytomas and pancreatic neuroendocrine tumors. The disease is the foremost cause of inherited renal cell carcinomas, which is induced by germline mutations of the VHL tumor-suppressor gene also inactivated in most sporadic renal cell carcinomas. VHL appears to be a pivotal gene in the oxygen-sensing pathway, mainly involved in targeting the hypoxia-inducible factors for ubiquitination. This discovery is opening the way for the development of new specific drugs inhibiting hypoxia-inducible factors and/or their downstream targets, possibly representing an attractive treatment not only for von Hippel-Lindau disease but also for sporadic renal cell carcinomas and others cancers.