Deceased donor kidney transplanted in childhood functioning well after 52 years.

BACKGROUND: Kidney transplantation in children in 1970 was considered by many to be unethical, as long-term survival was minimal. It was therefore risky at the time to offer transplantation to a child. CASE DIAGNOSIS/TREATMENT: A 6-year-old boy with kidney failure due to haemolytic uraemic syndrome received 4 months of intermittent peritoneal dialysis followed by 6 months of haemodialysis until at 6 years and 10 months, he underwent bilateral nephrectomy and received a kidney transplant from a deceased 18-year-old donor. Despite moderate long-term immunosuppression of prednisone (20 mg/48 h) and azathioprine (62.5 mg/day), at the last visit in September 2022, he was well, normotrophic, with a serum creatinine of 157 µmol/l (eGFR 41 ml/min/1.73 m2) and no haematuria, proteinuria or hypertension. Except for benign skin lesions due to azathioprine, and undergoing an aortic valve replacement and an aortic aneurysm repair in adulthood, the now 58-year-old man has had no major complications. CONCLUSIONS: We speculate that stable and unmodified immunosuppressive therapy, started before the era of calcineurin inhibitors, the lack of significant rejection episodes, the absence of donor-specific antibodies, and the young donor age have contributed to maintaining exceptional long-term kidney transplant survival. Luck, a robust health system and an adherent patient are also important. To the best of our knowledge, this is the longest functioning kidney transplant from a deceased donor performed in a child worldwide. Despite its risky nature at the time, this transplant paved the way for others.

Native kidney biopsies in Armenian and Swiss children: high prevalence of amyloidosis in Yerevan and of IgA nephropathy in Zurich.

The spectrum of pathology in native kidney biopsies varies considerably between different countries. Based on similar biopsy policy and joint workup, biopsy data of native kidneys of children in Yerevan (Armenia) and Zurich (Switzerland) were compared over a period of two decades (1993-2002 and 2003-2012). A total of 487 renal biopsies in Yerevan (EVN), n = 253; median age 11.2 years (range 0.8-18; 56 % males) and in Zurich (ZRH), n = 234; median age 8.7 years (range 0.1-18; 61 % males) were analyzed. Biopsies from EVN were locally analyzed by light microscopy (LM) and sent to ZRH for electron microscopy (EM) and immunohistochemistry. Biopsies from ZRH were evaluated by LM, EM, and immunofluorescence. The significant difference concerns the high frequency of amyloidosis in EVN (25.4 % in the first and 19.4 % in the second decade vs. 0 % in ZRH) and of IgA nephropathy in ZRH (30.2 % in the first and 26.1 % in the second decade vs. 8.1 in EVN). Certain forms of glomerulonephritis (membranoproliferative type I and membranous) and primary focal segmental glomerulosclerosis tended to be more frequent in EVN than in ZRH. Amyloid nephropathy due to familial Mediterranean fever is still highly frequent in Armenia with a slight decrease in the second decade. In Switzerland, the most common finding was IgA nephropathy.

Xanthinuria type I: a rare cause of urolithiasis.

Xanthinuria type I is a rare disorder of purine metabolism caused by xanthine oxidoreductase or dehydrogenase (XDH) deficiency. We report a family with two affected children out of 335 pediatric stone patients studied since 1991 in Armenia. The propositus, a 13-month-old boy, presented with abdominal pain and urinary retention followed by stone passage (0.9x0.6 cm). Infrared spectroscopy in Yerevan revealed a pure xanthine stone. Family examination in the parents and brother was normal, but the propositus and his 8-year-old asymptomatic sister had hypouricemia, hypouricosuria, and high urinary excretion of hypoxanthine and xanthine. Ultrasonography in the index patient showed bilateral stones requiring pyelolithotomy. High fluid intake and purine restriction did not prevent further stone passages. The affected asymptomatic sister had a small pelvic stone (4 mm). Mutation analysis revealed a heterozygous novel base pair substitution in exon 25 of the XDH gene (c.2810C>T), resulting in an amino acid substitution (p.Thr910Met). The second mutation could not be detected. Despite this, the heterozygous mutation, the chemical findings, and the positive allopurinol test altogether prove xanthinuria type I, which may present wide clinical intrafamilial variation. Diagnosis is suspected usually from low serum uric acid. No specific therapy is available.

Children with steroid-sensitive nephrotic syndrome come of age: long-term outcome.

OBJECTIVE: Long-term outcome of steroid-sensitive idiopathic nephrotic syndrome (SSNS) in children is usually considered benign, although data on follow-up into adulthood are scarce. The aim of this study was to investigate adults who had childhood SSNS regarding their relapse rate, growth, and renal and extrarenal morbidity. STUDY DESIGN: Adult patients (n=42, 26 males) were evaluated at a median age of 28.0 (18.1 to 46.9) years and a median follow-up of 22.0 (2.9 to 39.0) years since diagnosis. RESULTS: Fourteen of 42 (33%) patients relapsed in adulthood. The number of relapses during childhood and adolescence and a complicated course-administration of steroid-sparing medication such as cyclophosphamide, chlorambucil, and cyclosporin A-were identified as risk factors. Final adult height (median SD score -0.4, range -3.3 to +1.3) and body mass index (BMI) were normal. Renal function was normal in all patients, and overall morbidity was low. Only eight patients (three males) had children. Cytotoxic therapy was identified as a major factor contributing to childlessness. CONCLUSION: Relapses in adulthood were common in pediatric patients with SSNS. Growth and renal function were normal, and overall morbidity was low. Yet, transition to an adult nephrologist is recommended for all children with relapsing SSNS.

Primary hyperoxaluria type 1: is genotyping clinically helpful?

There is some controversy about the value of mutation analysis in the management of primary hyperoxaluria type 1 (PH1). About 50 different mutations of the AGXT gene encoding the liver-specific peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT) are currently known. The three most common mutations in the Western population account for less than half of the mutant alleles, and no simple screening test is available. Does the genotype help in diagnosis, prognosis and therapy? Definitive diagnosis is indispensable if liver transplantation is considered and can under certain circumstances be established by mutation analysis, but a liver biopsy is still necessary to determine AGT activity in a number of cases. Prognosis is difficult to assess due to a large clinical variation, despite identical mutations. Although the homozygous 508G>A (Gly170Arg) mutation appears to be associated with a better (and 33insC with a worse) prognosis, there are too many exceptions for precise prediction. Pyridoxine responsiveness can be anticipated in some genotypes (508G>A (Gly170Arg) and 454T>A (Phe153Ile)), but it should still be tested for in all patients. Genetic testing is thus clinically helpful but has clear limitations.

Diagnostic and therapeutic approaches in patients with secondary hyperoxaluria.

Secondary hyperoxaluria is due either to increased intestinal oxalate absorption or to excessive dietary oxalate intake. Certain intestinal diseases like short bowel syndrome, chronic inflammatory bowel disease or cystic fibrosis and other malabsorption syndromes are known to increase the risk of secondary hyperoxaluria. Although the urinary oxalate excretion is usually lower than in primary hyperoxaluria, it may still lead to significant morbidity by recurrent urolithiasis or progressive nephrocalcinosis. A clear distinction between primary and secondary hyperoxalurias is important. As correct classification may be difficult, appropriate diagnostic tools are needed to delineate the metabolic background as a basis for optimal treatment. We developed an individual approach for the evaluation of patients with suspected secondary hyperoxaluria. First, 24 h urines are examined repeatedly for lithogenic (e.g. calcium, oxalate, uric acid) and stone-inhibitory (e.g. citrate, magnesium) substances, and the patients are asked to fill in a dietary survey form. Urinary saturation is calculated using the computer based program EQUIL2, and the BONN-Risk-index is determined. The measurement of plasma oxalate and of urinary glycolate helps to distinguish between primary and secondary hyperoxalurias. If secondary hyperoxaluria is suspected, the stool is examined for Oxalobacter formigenes, an intestinal oxalate degrading bacterium, as lack or absence may lead to increased intestinal oxalate absorption. The last diagnostic step is to study the intestinal oxalate absorption using [13C2]oxalate. Depending on the results, various therapeutic options are available: 1) a diet low in oxalate, but normal or high in calcium, 2) a high fluid intake (>1.5 L/m2/d), 3) medications to increase the urinary solubility, 4) specific therapeutic measures in patients with malabsorption syndromes, depending on the underlying pathology, and 5) intestinal recolonization of Oxalobacter formigenes or the treatment with other oxalate degrading bacteria.

Confirmation of the ATP6B1 gene as responsible for distal renal tubular acidosis.

Primary distal renal tubular acidosis (dRTA) type I is a hereditary renal tubular disorder, which is characterized by impaired renal acid secretion resulting in metabolic acidosis. Clinical symptoms are nephrocalcinosis, nephrolithiasis, osteomalacia, and growth retardation. Biochemical alterations consist of hyperchloremic metabolic acidosis, hypokalemia with muscle weakness, hypercalciuria, and inappropriately raised urinary pH. Autosomal dominant and rare forms of recessive dRTA are known to be caused by mutations in the gene for the anion exchanger AE1. In order to identify a gene responsible for recessive dRTA, we performed a total genome scan with 303 polymorphic microsatellite markers in six consanguineous families with recessive dRTA from Turkey. In four of these there was an association with sensorineural deafness. The total genome scan yielded regions of homozygosity by descent in all six families on chromosomes 1, 2, and 10 as positional candidate region. In one of these regions the gene ATP6B1for the ss1 subunit of the vacuolar H(+)-ATPase is localized, which has recently been identified as causative for recessive dRTA with sensorineural deafness. Therefore, we conducted mutational analysis in 15 families and identified potential loss-of-function mutations in ATP6B1in 8. We thus confirmed that defects in this gene are responsible for recessive dRTA with sensorineural deafness.

Immunization in children with chronic renal failure.

Infections jeopardize children on immunosuppression after organ transplantation. Immunization is protective in healthy children. The aims of this study were to analyze the rate and efficacy of immunization in 62 children undergoing dialysis and renal transplantation (RTPL) between 1987 and 2000. The analysis was based on clinical findings, vaccination certificates, and measurement of specific serum antibodies. A member of the renal unit administered vaccinations. All 62 patients were immunized against diphtheria, tetanus, pertussis, poliomyelitis, measles, mumps, rubella, and hepatitis B. Since introduction in 1991 and 1995, 44 and 42 children were also vaccinated against influenza and Hemophilus influenzae type b, respectively. Of 16 patients with a negative history, 14 were given varicella vaccine; 16 children on peritoneal dialysis (PD) or with nephrotic syndrome were immunized against Streptococcus pneumoniae. All vaccinated patients had detectable serum antibodies against measles, mumps, rubella, varicella, hepatitis B, H. influenzae, and S. pneumoniae. There were 3 infections despite vaccination; 1 patient developed varicella after RTPL and 1 patient on PD had 2 episodes of peritonitis caused by H. influenzae and S. pneumoniae. In conclusion, monitoring and administration of the vaccines by the renal team enabled a high immunization rate. Whether vaccines, as documented by antibody titers, or by the low prevalence in the general population promoted the low prevalence of infections remains open, as there were at least a few vaccination failures.