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Primary BK virus (BKV) infections acquired mainly during childhood are usually asymptomatic. Several studies revealed its seroprevalence in adult population as high as 90% worldwide. Following primary infection, virus persists as latent infection in the urogenital tract. In renal transplant recipients, primary infection and reactivations affect 10% of patients and without treatment, more than half of these patients lose their grafts. The only way of preventing graft loss due to BKV nephropathy (BKVN), seems to monitor BKV infection after transplantation and to diagnose patients developing BKVN during the early period and treat them accordingly. In this study, we analyzed BKV presence in plasma and urine samples with real-time PCR method and evaluated the renal biopsies of pediatric renal transplant recipients after transplantation, retrospectively. A total of 142 children (63 female, 79 male; mean age: 11.7 ± 3.9 years) who had renal transplantation in Akdeniz University Medical Faculty, Antalya, Turkey, between February 2006 and April 2011 were enrolled in the study. After transplantation, peripheral blood and urine samples were collected bi-weekly for the first three months, monthly till the sixth month and every three months thereafter. BKV DNA was additionally screened in patients with unexplained rise in serum creatinine or in patients receiving anti-rejection therapy. In any plasma positivity or during the BKVN therapy, BKV DNA analysis was done bi-weekly. After DNA extraction by automated system, an 83 base pair fragment in VP1 region was amplified. Signal detection for the target region was performed with a TaqMan probe dual-labelled at the 5' end with 6-carboxyfluorescein (FAM) and the 3' end with 6-carboxytetramethylrhodamine (TAMRA). Histopathological examinations of renal biopsies were done with routine histological stains and immunohistochemical staining with monoclonal antibodies directed to SV40 antigen. From 2171 plasma and 1995 urine samples without PCR inhibitors, 442 (20%) (range: 300-4.5 x 10(7) copies/ml; mean: 2.0 x 10(5) ± 2.2 x 10(6) copies/ml) and 800 (40.1%) (range: 300-3 x 10(12) copies/ml; mean: 5.9 x 10(9) ± 1.1 x 10(11) copies/ml) were found positive for BKV DNA, respectively. For 114 (80.3%) patients, at least one urine sample was positive and more than half of those patients (68/114, 59.6%) had viremia. Of the patients, 19.7% (28/142) had viral DNA above 10(4) copies/ml, which was choosen as a cut-off value for its high positive predictive value for BKVN. For all these 28 patients, prior to renal biopsy, immunosupressive treatment was decreased. Cidofovir and/or leflunomid were initiated to nine patients who did not respond to lowered immunosupressive therapy and eight of them had renal biopsy for the confirmation of BKVN. All renal biopsy results were compatible with BKVN. From these nine patients who were receiving cidofovir and/or leflunomid, two lost their grafts because of BKVN. Since viruria is frequently encountered and the viral load is usually in low quantities and transient, it is more appropriate to use blood samples for screening programmes after renal transplantation. The efficacy of antiviral treatment in BKVN could not be evaluated since it was only applied in patients non-responding to lowered immunosuppressive therapy and had decreased renal functions. Multicenter prospective studies are required to enlighten this important issue. Early diagnosis with close monitoring of renal function and viremia, seems to be the most effective way for controlling BKVN.

The aim of this study was to analyze the etiology of nephrocalcinosis (NC) and whether it has any effect on growth and renal function in children. Forty-three children who were diagnosed with bilateral NC were studied retrospectively. Two neonates treated with furosemide and five premature infants were excluded from the study. The most common condition leading to NC was hereditary tubulopathies (50%). Data of 27 children who had a follow-up period of at least two years were examined in more detail. Of the 27 patients, the median age at first examination was 12 (range: 2-132) months and median follow-up time was 57 (range: 24-209) months. Thirteen of 27 (48.1%) patients had height standard deviation scores (hSDS) <-2 at presentation, and 6 (22.2%) patients who had normal glomerular function were still below -2 SDS at the last examination. Hypercalciuria was present in 25 (92.6%) patients at the first evaluation and in 6 (22.2%) patients at the last examination. The degree of NC worsened in 6 (22.2%), remained stable in 15 (55.5%) and decreased in 6 (22.2%) patients during the followup period. Chronic renal insufficiency (CRI) developed in 5 patients without there being any increase in the degree of NC. In conclusion, growth and renal function in these patients generally depend on the nature of the underlying disease but not the degree of NC.

Atypical hemolytic uremic syndrome (aHUS) is a disease caused by pathologies in the alternative complement system. The prevalence of aHUS is 10% of all aHUS cases. The subgroup of aHUS designated as DEAP (DEficiency of CFHR Proteins and CFH Autoantibody Positive)-HUS because of autoantibody to complement factor H (CFH) and CFH-related protein deficiency is seen very rarely, and the prevalence is 6% of all aHUS cases in the literature. We present here a female patient with DEAP-HUS. A 7.5-year-old girl with recurrent attacks of HUS had low C3 level. We initiated plasmapheresis treatment. After further analysis of the complement system, the result was compatible with DEAP-HUS, so we initiated immunosuppressive treatment. There were also family members with deficiency of CFHR-1 and CFHR-3, but they had no CFH autoantibody and no symptoms of HUS. In atypical cases of HUS, we should investigate complement status, especially for factor H autoantibody, for which treatment options differ from those of the other types of aHUS.

Hypothyroidism has been reported rarely as the cause of rhabdomyolysis in adults and children. We present here a non-compliant adolescent with a diagnosis of hypothyroidism who developed rhabdomyolysis and acute renal failure with no additional predisposing factor. A 13-year-old girl with a previous history of hypothyroidism due to thyroid hypoplasia presented with generalized myalgia, malaise, vomiting, and oliguria lasting for three days. Neurological examination revealed bilateral marked weakness and tenderness of muscles of both lower and upper extremities. Urine had bloody appearance and urine analysis showed blood reaction with dipstick test, but there were no erythrocytes on microscopic examination. Serum creatine phosphokinase and myoglobin levels were elevated. Thyroid stimulating hormone (TSH) levels were high, and free thyroxine (T4) and triiodothyronine (T3) levels were low, compatible with uncontrolled hypothyroidism. Renal function tests showed acute renal failure. Other causes of rhabdomyolysis such as muscular trauma, drugs, toxins, infections, vigorous exercise, and electrolyte abnormalities were excluded. Hemodialysis was administered for 24 sessions. After L-thyroxine therapy, thyroid function tests normalized, muscle strength improved, serum muscle enzyme levels returned to normal levels, and renal function tests recovered. One must be aware that rhabdomyolysis may develop in a non-compliant patient with hypothyroidism.

Considerable differences exist for the spectrum of GJB2 mutations in different populations. Screening for the c.35delG mutation in 256 independent probands, 154 multiplex (familial) and 102 simplex (sporadic), coming from different regions of Turkey revealed 37 (14.5%) homozygotes. The allele frequency of c.35delG ranged from 5% to 53% in different cities. Parental consanguinity was noted in 34% of c.35delG homozygotes, yet it was 55% in c.35delG negatives (p=0.034). Further screening for GJB2 mutations in multiplex families demonstrated the presence of c.167delT and L90P mutations as well as a novel complex mutation, c.236&#95;239delTGCAinsAGATCCG, in single alleles, leading to compound heterozygosity with c.35delG. The homozygous E120del mutation was found in another case. The V27I polymorphism was detected in five alleles, one of which was associated with the E114G change. Assortative mating was a significant factor predicting to detect biallelic mutations in the GJB2 gene. These results confirm the overwhelming majority of c.35delG in the Turkish deaf individuals as well as the presence of other changes detected in Caucasian and Asian populations., (Copyright 2003 Wiley-Liss, Inc.)