Vitamin D in renal transplantation - from biological mechanisms to clinical benefits.

Recent developments in our understanding of vitamin D show that it plays a significant role in immunological health, uniquely occupying both an anti-microbial and immunoregulatory niche. Vitamin D deficiency is widespread amongst renal transplant recipients (RTRs), thus providing one patho-mechanism that may influence the achievement of a successful degree of immunosuppression. It may also influence the development of the infectious, cardiovascular and neoplastic complications seen in RTRs. This review examines the biological roles of vitamin D in the immune system of relevance to renal transplantation (RTx) and evaluates whether vitamin D repletion may be relevant in determining immunologically-related clinical outcomes in RTRs, (including graft survival, cardiovascular disease and cancer). While there are plausible biological and epidemiological reasons to undertake vitamin D repletion in RTRs, there are few randomized-controlled trials in this area. Based on the available literature, we cannot at present categorically make the case for routine measurement and repletion of vitamin D in clinical practice but we do suggest that this is an area in urgent need of further randomized controlled level evidence.

Uric acid as a cardiorenal risk factor - ready for prime-time?

Patients with cardiac morbidity are known to have increased risk of developing renal disease, and vice versa. Cardiorenal syndrome is a general term describing concomitant cardiac and renal dysfunction, and recently there has been renewed interest in the role of uric acid (UA) in its pathophysiology and management. There is evidence to suggest that UA-lowering drugs, such as the xanthine oxidase (XO) inhibitors allopurinol and Febuxostat, may not only retard deteriorating renal function in the context of chronic kidney disease (CKD) but also confer protective cardiovascular effects. As these diseases represent considerable health burdens, this evidence merits evaluation to determine whether or not hyperuricaemia is a cardiorenal risk factor that necessitates intervention and if existing pharmacological agents are sufficiently efficacious.

Cardiovascular disease in chronic kidney disease: untying the Gordian knot.

Chronic kidney disease (CKD) affects around 10-13% of the general population, with only a small proportion in end stage renal disease (ESRD), either on dialysis or awaiting renal transplantation. It is well documented that CKD patients have an extremely high risk of developing cardiovascular disease (CVD) compared with the general population, so much so that in the early stages of CKD patients are more likely to develop CVD than they are to progress to ESRD. Various pathophysiological pathways and explanations have been advanced and suggested to account for this, including endothelial dysfunction, dyslipidaemia, inflammation, left ventricular hypertrophy and cardiac autonomic dysfunction. In this review, we try to understand and further explore the link between CKD and CVD, as well as offering interventional advice where available, while exposing the current lack of RCT-based research and trial evidence in this area. We also suggest pragmatic Interim measures we could take while we wait for definitive RCTs.

Fibroblast growth factor-23 is associated with C-reactive protein, serum phosphate and bone mineral density in chronic kidney disease.

UNLABELLED: We investigated the association between fibroblast growth factor-23 (FGF-23) and (1) the biochemical parameters implicated in chronic kidney disorder (CKD)-bone and mineral disorder (CKD-MBD) and (2) bone mineral density (BMD) in patients with CKD 1-4. C-reactive protein (CRP) and serum phosphate correlated with FGF-23. A significant association was seen between FGF-23 and BMD at the hip. INTRODUCTION: Circulating FGF-23 is elevated in CKD, although the primary stimulus remains unclear. Moreover, it is still unknown whether increase in FGF-23 has a biological effect on bone metabolism. The aim of the study was to investigate the association of FGF-23 with (1) the biochemical parameters linked with CKD-bone and mineral disorder (CKD-MBD) and (2) bone mineral density in CKD. METHODS: We studied 145 patients (74 M, 71 F) aged (mean [SD]) 53 [14] years with CKD 1-4. Serum calcium, phosphate, parathyroid hormone, FGF-23, 25 (OH) vitamin D, 1, 25 (OH)(2) vitamin D, bone turnover markers, CRP were determined. BMD was measured at the lumbar spine, femoral neck (FN), forearm, and total hip (TH). Multivariate analysis was undertaken to explore the association between (1) the biochemical variables and FGF-23 and (2) FGF-23 and BMD. RESULTS: Elevations in FGF-23 occurred in CKD stage 3 compared to CKD stage 1/2, although no significant differences in serum phosphate were observed. Serum phosphate (p<0.001), CRP (p<0.001) and diabetes mellitus (p<0.05) were associated with FGF-23. BMD Z-score was significantly lower at the TH and FN in CKD 4 (p<0.05). A significant association was seen between BMI, FGF-23, bone specific alkaline phosphatase and BMD at the TH (p<0.05). CONCLUSIONS: The data suggest that FGF-23 may be associated with parameters implicated in the complications of CKD. Longitudinal studies are required for further clinical evaluation.

4-pyridone-3-carboxamide ribonucleoside triphosphate accumulating in erythrocytes in end stage renal failure originates from tryptophan metabolism.

We recently identified an erythrocyte nucleotide accumulating in end-stage renal disease as 4-pyridone-3-carboxamide ribonucleotide triphosphate (4PYTP), a nucleotide never described previously. Plasma tryptophan concentration has been previously reported to be reduced in patients in chronic renal failure that is in turn associated with elevated precursors of tryptophan metabolism, including L -kynurenine and quinolinic acid, both of which have been implicated in the neurotoxic manifestations of chronic renal failure. Here we compare mean erythrocyte 4PYTP, and plasma tryptophan concentrations, in controls and four patient groups with renal impairment (10 per group) and confirmed a reduction in plasma tryptophan in patients on dialysis that corrected with renal transplantation. We found: An inverse correlation between plasma tryptophan and red cell 4PYTP concentrations (R(2)=0.44, P<0.001) when all patients were grouped together. Restoration of both tryptophan and 4PYTP concentrations to control values was only achieved following renal transplantation. 4PYTP was absent from erythrocytes in Molybdenum cofactor (MoCF) deficiency implicating aldehyde oxidase/dehydrogenase, a Molybdenum requiring enzyme. High 4PYTP erythrocyte concentrations in adenine or hypoxanthine-phosphoribosyltransferase deficient patients in severe uremia (113 microM and 103 microM), confirmed the lack of involvement of either enzyme in 4PYTP formation. We propose that 4PYTP is formed by a novel route involving the oxidation of the intermediates of NAD turnover from quinolinic acid by aldehyde oxidase.

Chronic renal allograft dysfunction: the evidence for a change in immunosuppression.

In renal transplantation the calcineurin inhibitors (CNIs) have played a crucial role in the reduction in acute rejection rates. Unfortunately this has not been matched by an improvement in long-term graft survival rate. The development of chronic allograft nephropathy (CAN) is the second most common cause of graft loss, after death from cardiovascular causes. CAN has a multifactorial aetiology that includes immunological and nonimmunological factors relating to both donor and recipient. The use of CNIs has been strongly implicated as a risk factor for the development of CAN. With the ongoing development of new immunosuppressant agents the possibility of avoiding the CNIs now exists. Many studies have been designed to investigate strategies to minimise or avoid CNI exposure and to prolong graft survival. To achieve CNI withdrawal whilst avoiding rejection, additional immunosuppressants need to be substituted into the drug regimen. Long-term side effects of the immunosuppressant used need to be taken into account when drug changes are being considered. In light of current evidence, CNI reduction with optimal use of mycophenolate mofetil appears to be the most effective strategy in managing the patient with CAN.

Familial juvenile hyperuricaemic nephropathy is not such a rare genetic metabolic purine disease in Britain.

Renal disease is rare today in classic adult gout, and gout is rare in renal disease--especially in the young. Here we summarise studies in 158 patients from 31 kindreds diagnosed with familial juvenile hyperuricaemic nephropathy FJHN from a total of 230 kindred members studied in Great Britain. Some patients have been followed for up to 30 years, and allopurinol has ameliorated the progression of the renal disease in all 113 surviving members provided: They have been diagnosed and treated sufficiently early. Compliance with allopurinol treatment and diet has been as important as early recognition. Hypertension has been rigorously controlled. The use of oral contraceptives has been avoided, as has pregnancy in any female with a Glomelar Filtration Rate GFR <70 ml/min. The question arising is: Why is FJHN the most prevalent genetic purine disorder diagnosed in Britain? Is it a lack of awareness which needs to be improved Europe-wide?

Antiangiogenic agents: studies on fumagillin and curcumin analogs.

Cancer is a general term used to describe many disease states, each of which are characterized by abnormal cell proliferation. The causes which bring about this abnormal cellular behavior are specific to each type of cancer. The success of tumor-targeted therapy is limited by this diversity. One common denominator for all types of cancer is the requirement of a suitable blood supply. Therefore, tumor vasculature has emerged as a potential target for therapeutic intervention. New blood vessel growth from preexisting vasculature stimulated by biochemical signals is termed angiogenesis. Tumor masses require a constant supply of oxygen and nutrients, and a means of efficient waste removal to ensure sustained development. Diffusion from nearby capillaries can supply adequate nutrition for tumors less than 2 mm in size, but for continued growth the tumors must develop their own blood supply. Alteration of the delicate balance of angiogenic stimulating factors and angiogenic inhibitors results in the phenotypic change from quiescence to active endothelial proliferation. To date, this angiogenic switch is not completely understood. The goal of antiangiogenic therapy is to interfere with these mechanisms and prevent tumor cells from developing a viable blood supply. Fumagillin is a naturally occurring antifungal agent. Curcumin is a natural product isolated from the spice turmeric. Both compounds have been shown to have antiangiogenic properties in vitro and in vivo. This paper describes efforts to design and prepare fumagillin and curcumin analogs and evaluate their corresponding antiangiogenic activities.

Aortic pulse wave velocity and arterial wave reflections predict the extent and severity of coronary artery disease in chronic kidney disease patients.

BACKGROUND: Increased aortic stiffness markers - aortic pulse wave velocity (PWV) and augmentation index (AIx) - are powerful predictors of survival in ESRD patients - well-recognized for the high prevalence of coronary artery disease (CAD) and unusually high PWV and AIx. Recently, decreased aortic compliance has been shown to be predictive of primary coronary events in hypertensive patients with normal renal function. We aimed to explore relationships between arterial stiffness and CAD in cohorts of patients with chronic kidney disease (CKD). METHODS AND RESULTS: 46 patients with chronic kidney disease (33 males, aged 55.7+/- 13.2 years, 20 on dialysis, 18 post renal transplantation, and 8 with glomerular filtration rate (GFR) between 10 and 25 ml/min) underwent coronary angiography for the assessment of CAD. PWV and aortic AIx were determined from pulse waveform analysis of arterial waveforms recorded by applanation tonometry using a SphygmoCortm device. The atherosclerosis burden score was calculated by adding the percentage luminal reduction of the most severe lesion in each artery. Patients with normal angiograms had significantly less arterial stiffness (as reflected by both a lower PWV=8.42+/-1.53 m/s and a lower AIx=17.9+/-5.55 %) compared with the 35 subjects with evidence of obstructive coronary disease at angiography (PWV=9.21+/-1.15 m/s and AIx=23.4+/-5.4 %, P<0.05 for both). Moreover, as more coronary vessels were affected, PWV and AIx increased proportionally. Based on receiver operating characteristics (ROC) curve analysis mean PWV levels showed an optimal cut-off point at 8.35 m/s (sensitivity=0.77; specificity=0.60), while mean AIx levels showed an optimal cut-off point at 17% (sensitivity=0.87; specificity=0.70). There was a statistically significant linear relationship between the atherosclerosis burden and both measures of arterial stiffness: PWV (r=0.31, p=0.007) and AIx (r=0.46, p=0.003). Independent predictors for the arterial stiffness parameters in this CKD population (multiple stepwise regression analysis) were age (r=0.69 for PWV and r=0.62 for AIx), and mean arterial pressure (MAP) (for AIx, p<0.0001). CONCLUSION: This study provides the first direct evidence in a cross-sectional investigation that PWV and AIx are related to the extent of coronary obstruction in CKD patients.

Endothelin-induced contraction of human peripheral resistance vessels is partly dependent on stimulation of sodium-hydrogen exchange.

The role of Na-H exchange in endothelin-induced contraction of human peripheral resistance vessels was investigated. Endothelin produced a dose-dependent contraction which was greatly attenuated in the presence of a low extracellular sodium concentration. Inhibition of Na-H exchange by the amiloride analogue 5-(N,N-hexamethylene) amiloride (5-NNHA) resulted in a greater than 65% relaxation of a maximal endothelin-induced contraction in the presence of normal extracellular sodium. However, in the presence of a low extracellular sodium concentration, inhibition of Na-H exchange only resulted in a 25% relaxation. These data suggest that endothelin-induced vasoconstriction of human peripheral resistance vessels is mediated in part by stimulation of Na-H exchange.

Leucocyte intracellular pH and Na(+)-H+ exchange activity in essential hypertension: an in vitro study under physiological conditions.

The cellular basis for essential hypertension remains obscure. Abnormal ion transport has been demonstrated in both experimental and essential hypertension, raised levels of sodium-lithium (Na(+)-Li+) and sodium-proton (Na(+)-H+) exchange in blood cells being a consistent feature. However, Na(+)-H+ exchange is not the main regulator of intracellular pH at resting pH, while the importance of the contribution of bicarbonate to cellular pH regulation is now increasingly appreciated. Serum and serum-derived growth factors are known to affect intracellular pH and the activity of the Na(+)-H+ antiporter. This study was designed to investigate the activity of Na(+)-H+ exchange in the leucocytes of patients with essential hypertension in the presence of bicarbonate in vitro and to measure the effect of autologous serum on intracellular pH and Na(+)-H+ exchange. Paired serum samples from essential hypertensives and their controls were used on leucocytes from other (unrelated, normotensive) donors to investigate the same parameters. In a study of 30 patients with untreated essential hypertension and 30 controls matched for age, sex, race and body habitus we found no difference in resting pH or buffering capacity (pH 7.28 +/- 0.01 and 32.0 +/- 1.6 mmol/l per pH, hypertensives, versus 7.27 +/- 0.02 and 34.5 +/- 1.8 mmol/l per pH, controls) but a marked difference in the maximal rate of Na(+)-H+ exchange in response to intracellular acidification (57.8 +/- 3.2 mmol/l per min versus 47.2 +/- 1.4 mmol/l per min, P = 0.004).(ABSTRACT TRUNCATED AT 250 WORDS)

Successful renal transplantation decreases aortic stiffness and increases vascular reactivity in dialysis patients.

BACKGROUND: Patients with end-stage renal disease on dialysis have among the highest cardiovascular event rates documented. Abnormal nitric oxide (NO)-dependent endothelial reactivity and increased arterial stiffness are commonly described in hemodialysis (HD) patients. Measures of aortic stiffness--aortic pulse wave velocity (PWV) and augmentation index (AGI)--have been shown to be powerful predictors of survival on hemodialysis. It is not known how these parameters interfere with successful renal transplantation. METHODS: PWV and aortic AGI (difference between the first and second systolic peak on the aortic pressure waveform divided by the pulse wave height) were determined from contour analysis of arterial waveforms recorded by applanation tonometry using a SphygmoCor device in 41 HD patients (20 men; age, 41.8 years) and in a control group of 20 patients with essential hypertension (HTA) (10 men; age, 43.6 years). Twenty of the HD patients (10 men; age, 39.7 years) received live-related renal transplants (RTx) and were restudied (3 months after RTx, normal serum creatinine). NO-dependent and NO-independent vascular reactivity were assessed by changes in AGI after challenges with inhaled salbutamol (SAL) and sublingual nitroglycerin (NTG), respectively. RESULTS: AGI values were significantly lower in RTx patients compared with subjects on hemodialysis (15.9 +/- 13.9% vs. 27.9 +/- 11.9%, P<0.05), but similar to essential HTA controls (16.5 +/- 17%). Serial AGI measurements showed that successful renal transplantation is associated with a decrease in AGI in all cases, from a mean of 25.1 +/- 7.8% while on dialysis to 15.9 +/- 7.0% 3 months after transplantation (P<0.0001). The responsiveness to both endothelium-dependent stimuli (inhaled SAL) and endothelium-independent stimuli (sublingual NTG) was greater in transplant patients than in hemodialysis patients (SAL-induced decrease in AGI -82.3 +/- 65.7% vs. 45 +/- 72.3%, P<0.01; and NTG-induced decrease in AGI 197 +/- 108 vs. -129.0 +/- 215.5%, P<0.01). PWV values in dialysis patients (7.19 +/- 1.88 m/sec) were significantly higher than those measured in essential HTA patients (6.34 +/- 1.32 m/sec, P<0.05) with normal renal function (despite similar blood pressure levels). PWV after RTx was 6.59 +/- 1.62 m/sec, significantly different from pretransplantation (dialysis) values (P<0.05 for comparison) but similar to the control group of essential HTA patients. CONCLUSIONS: Renal transplantation is associated with marked improvements in vascular structure and function to a profile comparable to essential HTA patients.

Renal arterial intervention and angiotensin blockade in atherosclerotic nephropathy.

Atherosclerotic renal arterial disease (ARAD) is becoming a more important cause of end-stage renal failure. Diagnosis is more easily achieved because of greater clinical suspicion and more refined screening tools. However, the medical and interventional management of patients with ARAD is not well defined in the literature because there have been few randomized trials. Because the use of angiotensin-converting enzymes (ACE) inhibitors, and more recently angiotensin-antagonists, has become much more widespread, it is inevitable that we should, knowingly or not, give these drugs to patients with ARAD. We describe 2 case studies in which the angiotensin-antagonist irbesartan was given to 2 patients with effectively single-functional kidneys after successful renal arterial radiologic intervention. The rationale for the use of irbesartan was to control BP, which had not responded to the initial arterial intervention, and took place in patients both refractory to, and intolerant of, many other anti-hypertensive drugs. Irbesartan successfully and safely reduced systemic BP, measured by use of ambulatory BP, without prejudicing renal function (measured by use of individual kidney function GFR).

Parathyroid carcinoma in a dialysis patient.

A 75-year-old woman who had been receiving dialysis for 3 years and had a long history of chronic renal failure attributable to reflux nephropathy was investigated for progressive hypercalcemia in the context of very high intact parathormone (iPTH) levels. Imaging showed two functional parathyroid glands in the neck. At parathyroidectomy, four variously enlarged parathyroid glands were found and completely resected, without autotransplantation. The histology of one of the glands showed invasive parathyroid carcinoma. Parathyroid carcinoma is a very rare condition, with only 16 previous cases involving dialysis patients described in the literature. We review the literature to draw together presentational and therapeutic information on the management of this problem in the setting of renal replacement therapy.

Reduced blood pressure diurnal variability as a risk factor for progressive left ventricular dilatation in hemodialysis patients.

Cardiovascular mortality places a considerable burden on chronic renal replacement therapy programs. Left ventricular hypertrophy (LVH) increases the risk for cardiovascular mortality. Risk factors for LVH in the dialysis population are numerous and include arterial distensibility, hypertension, anemia, arteriovenous fistula, and hyperparathyroidism. An important factor to consider in the diagnosis and evaluation of hypertension in this clinical setting is blood pressure (BP) level variation, only accessible using ambulatory BP monitoring (ABPM). In uremic patients, a relative elevation of BP during sleep periods leading to an increased 24-hour BP load is frequently described. Whether this additional BP burden is pathophysiologically significant has not been resolved. This study is designed to examine the effect on echocardiographically derived measurements of the left ventricle in 60 stable chronic hemodialysis patients of abnormal (reduced) diurnal BP variability, measuring ambulatory BP on three occasions and performing echocardiography twice over a 12-month period. First, we found that most dialysis patients (76%) had consistent diurnal BP rhythms over a 12-month period, and second, those patients with persistently reduced diurnal BP rhythm tended to develop a dilated left ventricle and left atrium in the absence of other known and/or relevant risk factors (persistently increased sleep BP group; n = 36; LV end-diastolic diameter, 38.2 +/- 2.5 mm/m(2) versus persistently normal sleep BP group; n = 10; LV end-diastolic diameter, 30.6 +/- 3. 3 mm/m(2); P < 0.05). These results suggest that persistent abnormal BP variability is a risk factor for a dilated heart on dialysis, independent of the BP level.

Facet joint osteomyelitis in a patient on long-term hemodialysis.

Spinal osteomyelitis is a recognized complication in dialysis patients related to hematogenous spread of infection during bacteremia-septicemia. These episodes are often associated with sepsis due to temporary dialysis access. We describe the case of an unfortunate man whose osteomyelitis was located in the posterior facet joints. Such infection is rare and in the reviewed literature is usually associated with a more favorable outcome than described here.

Successful medical treatment of acute bilateral emphysematous pyelonephritis.

Emphysematous pyelonephritis most often presents as an acute medical emergency, typically in a septic diabetic patient with acute renal failure. The management of this condition has traditionally been surgical, with nephrectomy. However, some recent reports have described successful medical interventions. We describe a case of acute bilateral emphysematous pyelonephritis in a frail patient not suitable for bilateral nephrectomy and long-term dialysis. This condition was managed medically, not surgically, with intensive antibiotic and circulatory support. The outcome was complete recovery after months of hospital-based treatment. We discuss the management of this rare but important condition in detail.

Long-hours home haemodialysis--the best renal replacement therapy method?

Two hundred and eighty-six patients (190 males and 96 females) with end-stage renal failure (ESRD) started haemodialysis (HD) at Withington Hospital between 1 January 1968 and 31 December 1986. Of these, 152 (53.1%) were successfully transplanted, while 134 had only HD or one transplant lasting < 3 months (i.e. total HD interruption < 3 months). For the whole group, the probabilities of being alive on long-hours home HD at 10 and 20 years were 58.7% and 33.2%, respectively. Mean gross mortality 1968-1986 was 6.5 +/- 3.2% per year. The main causes of death were cardiovascular (36.6%), infection-related (19.2%) and malignancy (9.6%). Males and younger cohorts had a significantly (p < 0.05) higher probability of being alive on long-hours home HD than did females and older cohorts. Eighty-two patients (29% of the total group) survived more than 10 years, of whom 54 were still alive at 1 January 1996: 44 continuing on HD while the other ten had been successfully transplanted. In these 54 patients, mean 24-h ambulatory blood pressure recorded at the date of the study was 117.6/68.9 mmHg; mean BP for the last 5 years on HD was 136.4/81.2 mmHg. Only four (7.4%) were regularly taking antihypertensive medication. Left ventricular hypertrophy (LVH) (by ECG) was present in 64.8% of the 54 patients; its prevalence by echocardiography (LVM index > 130 g/m2 for men and > 110 g/m2 for women) was 77.5%. Only 10 (18.5%) had symptoms or clinical signs of ischaemic heart disease and/or peripheral vascular disease. None had cardiac failure symptoms NYHA class 3-4. Our data show a low incidence of all-cause and cardiovascular mortality, confirming those from the Tassin unit in France, and make a medical case for extended haemodialysis treatment hours.

Treating paracetamol overdose by charcoal haemoperfusion and long-hours high-flux dialysis.

After serious paracetamol overdose, charcoal haemoperfusion was used to remove paracetamol from the circulation, aiming to reduce the severity of subsequent hepatic damage. Daily long-hours high-flux dialysis was given to patients with grade III-IV hepatic encephalopathy, and also to those at risk of developing encephalopathy. We reviewed patients treated in this manner who had not received N-acetylcysteine within the first 15 h after overdose. From January 1983 to January 1993, 73 patients with serious paracetamol overdose were seen, of whom 51 received charcoal haemoperfusion and/or high-flux dialysis. Patients who were admitted within the first 42 h after overdose and who received haemoperfusion and/or dialysis had significantly lower peak levels of prothrombin time, bilirubin and creatinine than those who were admitted after 42 h. Mortality was also lower amongst patients admitted before 42 h, at 2/18 (11%) vs. 15/33 (45%), p < 0.05.

Early treatment with allopurinol in familial juvenile hyerpuricaemic nephropathy (FJHN) ameliorates the long-term progression of renal disease.

BACKGROUND: The efficacy of allopurinol in autosomal dominant familial juvenile hyperuricaemic nephropathy (FJHN) has been disputed. AIM: To address this question, in the absence of controlled trials. DESIGN: Retrospective long-term follow-up study. METHODS: All kindreds were biochemically screened. Measurements included uric acid clearance, creatinine clearance, serum creatinine, and glomerular filtration rate (GFR). We used five siblings who had died or progressed to transplantation, ten other deceased relatives, and two index cases (one untreated, one non-compliant) as controls to assess the effects of allopurinol. RESULTS: Of eight families with FJHN, six had a strong history of renal disease and early parental death (mean age 41 years, n=10). Of 27 patients started immediately on allopurinol and treated uninterruptedly, 21 responded well, including three children born subsequently. Eight siblings (mean age 19 years) with a normal plasma creatinine at start (<120 micromol/l, mean GFR 80 ml/min/1.73 m(2)) retained stable renal function (mean 14.5 years, mean age 34 years, GFR 85 ml/min/1.73 m(2)). Of the 13 other responders, treated for up to 34 years, 10 with a creatinine <200 micromol/l at diagnosis (mean age 28 years, mean creatinine 137 micromol/l at start) now have a mean creatinine of 210 micromol/l. In contrast, five patients (mean age 26 years) with a creatinine >200 micromol/l (GFR <35 ml/min/1.73 m(2)) when allopurinol commenced, plus one untreated index case, all progressed rapidly (mean 6 years) to end-stage renal failure. In two others (one non-compliant, one initially untreated), GFR fell by >50% in 7 years. Introduction of allopurinol in the latter has stabilized GFR. DISCUSSION: Allopurinol reduced the morbidity and mortality from renal failure seen in untreated siblings and previous generations of these families. Early diagnosis of FJHN is important, so that treatment can begin before irreversible renal damage has developed.