Safak Gucer

Disruption of ALX1 Causes Extreme Microphthalmia and Severe Facial Clefting: Expanding the Spectrum of Autosomal-Recessive ALX-Related Frontonasal Dysplasia

We present an autosomal-recessive frontonasal dysplasia (FND) characterized by bilateral extreme microphthalmia, bilateral oblique facial cleft, complete cleft palate, hypertelorism, wide nasal bridge with hypoplasia of the ala nasi, and low-set, posteriorly rotated ears in two distinct families. Using Affymetrix 250K SNP array genotyping and homozygosity mapping, we mapped this clinical entity to chromosome 12q21. In one of the families, three siblings were affected, and CNV analysis of the critical region showed a homozygous 3.7 Mb deletion containing the ALX1 (CART1) gene, which encodes the aristaless-like homeobox 1 transcription factor. In the second family we identified a homozygous donor-splice-site mutation (c.531+1G > A) in the ALX1 gene, providing evidence that complete loss of function of ALX1 protein causes severe disruption of early craniofacial development. Unlike loss of its murine ortholog, loss of human ALX1 does not result in neural-tube defects; however, it does severely affect the orchestrated fusion between frontonasal, nasomedial, nasolateral, and maxillary processes during early-stage embryogenesis. This study further expands the spectrum of the recently recognized autosomal-recessive ALX-related FND phenotype in humans.

ADCK4-Associated Glomerulopathy Causes Adolescence-Onset FSGS

Hereditary defects of coenzyme Q10 biosynthesis cause steroid-resistant nephrotic syndrome (SRNS) as part of multiorgan involvement but may also contribute to isolated SRNS. Here, we report 26 patients from 12 families with recessive mutations in ADCK4. Mutation detection rate was 1.9% among 534 consecutively screened cases. Patients with ADCK4 mutations showed a largely renal-limited phenotype, with three subjects exhibiting occasional seizures, one subject exhibiting mild mental retardation, and one subject exhibiting retinitis pigmentosa. ADCK4 nephropathy presented during adolescence (median age, 14.1 years) with nephrotic-range proteinuria in 44% of patients and advanced CKD in 46% of patients at time of diagnosis. Renal biopsy specimens uniformly showed FSGS. Whereas 47% and 36% of patients with mutations in WT1 and NPHS2, respectively, progressed to ESRD before 10 years of age, ESRD occurred almost exclusively in the second decade of life in ADCK4 nephropathy. However, CKD progressed much faster during adolescence in ADCK4 than in WT1 and NPHS2 nephropathy, resulting in similar cumulative ESRD rates (>85% for each disorder) in the third decade of life. In conclusion, ADCK4-related glomerulopathy is an important novel differential diagnosis in adolescents with SRNS/FSGS and/or CKD of unknown origin.

Expression of ASC in renal tissues of familial mediterranean fever patients with amyloidosis: postulating a role for ASC in AA type amyloid deposition.

Familial Mediterranean fever (FMF) is characterized by recurrent attacks of fever and serositis; in some cases, ensuing amyloidosis results in kidney damage. Treatment with colchicine reduces the frequency and severity of FMF attacks and prevents amyloidosis, although the mechanisms behind these effects are unknown. Pyrin, the protein product of the MEFV gene, interacts with ASC, a key molecule in apoptotic and inflammatory processes. ASC forms intracellular speck-like aggregates that presage cell death. Here we show that cell death after ASC speck formation is much slower in nonmyeloid cells than in myeloid cells. Additionally, we demonstrate that colchicine prevents speck formation and show that specks can survive in the extracellular space after cell death. Because we also found that ASC is expressed in renal glomeruli of patients with FMF but not in those of control patients, we posit that high local ASC expression may result in speck formation and that specks from dying cells may persist in the extracellular space where they have the potential (perhaps in association with pyrin) to nucleate amyloid. The fact that speck formation requires an intact microtubule network as shown here could potentially account for the ability of prophylactic colchicine to prevent or reverse amyloidosis in patients with FMF.

Mutations in ANKS6 Cause a Nephronophthisis-Like Phenotype with ESRD

Nephronophthisis (NPHP) is one of the most common genetic causes of CKD; however, the underlying genetic abnormalities have been established in <50% of patients. We performed genome-wide analysis followed by targeted resequencing in a Turkish consanguineous multiplex family and identified a canonic splice site mutation in ANKS6 associated with an NPHP-like phenotype. Furthermore, we identified four additional ANKS6 variants in a cohort of 56 unrelated patients diagnosed with CKD due to nephronophthisis, chronic GN, interstitial nephritis, or unknown etiology. Immunohistochemistry in human embryonic kidney tissue demonstrated that the expression patterns of ANKS6 change substantially during development. Furthermore, we detected increased levels of both total and active β-catenin in precystic tubuli in Han:SPRD Cy/+ rats. Overall, these data indicate the importance of ANKS6 in human kidney development and suggest a mechanism by which mutations in ANKS6 may contribute to an NPHP-like phenotype in humans.

Acute kidney injury due to acyclovir

Acyclovir is an antiviral agent widely used in herpetic infections in children. Although acyclovir is generally well tolerated, severe nephrotoxicity has been reported in some cases. In this report, we present a 16-year-old girl who developed acute renal failure due to acyclovir treatment and who needed repetitive hemodialysis. Renal biopsy was performed in order to confirm the diagnosis. A diagnosis of drug-related acute tubulointerstitial nephritis with focal tubular necrosis was made.

Zellweger syndrome with unusual findings: non-immune hydrops fetalis, dermal erythropoiesis and hypoplastic toe nails

The peroxisomal biogenesis disorders (PBDs) comprise the Zellweger spectrum disorders (i.e., Zellweger syndrome, neonatal adrenoleukodystrophy, and infantile Refsum disease) and rhizomelic chondrodysplasia punctata. Peroxisomal biogenesis disorders can be caused by mutations in any of 13 currently known PEX genes, which encode peroxins involved in peroxisomal protein import and/or assembly of the organelle. We report here on a Turkish patient who presented with unusual clinical findings, that included non-immune hydrops, dermal erythropoiesis and hypoplastic toenails, as well as common dysmorphic features of Zellweger syndrome. The patient has also pulmonary hypoplasia, which has been reported in only a few patients with Zellweger syndrome. A peroxisomal biogenesis disorder was confirmed by enzyme analysis and abnormal very long-chain fatty acid (VLCFA) profiles in plasma and fibroblast and immunofluorescence microscopy studies. Subsequent molecular genetic analysis revealed a homozygous c.856C>T mutation (R268X) in the PEX3 gene, which made this patient the third to have a defect in this gene. In contrast to those of the two previously reported patients, the cells of this patient still contained peroxisomal membrane structures (ghosts), seen by immunofluorescence microscopy analysis. The case presented here and the two previously reported cases point out that a PEX3 gene defect may present with fairly heterogeneous clinical findings. This case also raises a possibility that hydrops fetalis may be associated with a PEX3 gene defect and that peroxisomal disorders can be considered in the etiology of hydrops fetalis as well as other cell organelle disorders when one is considering yet undiscovered complementation groups in peroxisomal disorders.

Familial Mediterranean fever and mesangial proliferative glomerulonephritis: report of a case and review of the literature

In familial Mediterranean fever (FMF), a genetically inherited disease characterized by fever and serositis, renal involvement is mainly AA amyloidosis. We report a patient with FMF who developed mesangial proliferative glomerulonephritis; presumably in response to colchicine treatment, the activity of the disease decreased and renal function tests and urinary findings normalized. This report emphasizes the concurrent existence of mesangial proliferative glomerulonephritis with FMF in the absence of renal amyloidosis. Due to increased inflammatory response observed in FMF, immunologic glomerular injury, a common cause of glomerulonephritis, may occur more frequently in patients with FMF.

Four-Month-Old Infant With Focal Segmental Glomerulosclerosis and Mitochondrial DNA Deletion

Mitochondrial cytopathies are a group of heterogeneous disorders characterized by multisystem involvement. Renal involvement in mitochondrial cytopathies is usually manifested as tubular dysfunction owing to impaired energy metabolism; however, a few cases with glomerular changes have also been reported. Herein we report the case of a 4-month-old Turkish girl with a mitochondrial DNA deletion and focal segmental glomerulosclerosis. (J Child Neurol 2005;20:83—84).

Trichosporon asahii sepsis in a patient with pediatric malignancy

Trichosporon asahii is a rare opportunistic infection, especially in children, causing a life-threatening fungal infection underlying hematologic malignancies. Predisposing factors for infection with this pathogen are immunodeficiency including underlying malignancy, organ transplantation, extensive burns, human immunodeficiency virus infection, corticosteroid therapy, prosthetic valve surgery, and peritoneal dialysis. In the literature, a breakthrough under caspofungin, micafungin therapy is reported. In this article we report on a 16-year-old patient with Ewing sarcoma who had T. asahii sepsis. The patient died although he had been receiving caspofungin for less than 3 months and amphotericin B therapy for 3 days. A postmortem study of conchal tissues revealed T. asahii and mucormycosis histopathologically, and blood culture grew T. asahii.

Prenatal echocardiographic diagnosis of cardiac right/left axis and malpositions according to standardized Cordes technique.

OBJECTIVE The aim of this study was to evaluate distinguishing the right/left side of the fetus, cardiac axis and position according to the standardized Cordes technique in 20 cases with cardiac malposition. METHODS We studied retrospectively 1536 cases whose fetal echocardiographic examinations were performed between 1999 and 2006 in prenatal cardiology unit. Among these, cardiac malpositions were determined in 20 cases. The cardiac axis and position were determined according to the Cordes technique. All cases were followed-up by serial fetal echocardiograms until birth or intrauterine death occurred. In cases of intrauterine death, an autopsy was performed. After birth, physical and echocardiographic examinations were done and prenatal and postnatal diagnoses were compared. RESULTS Of 1536 fetal echocardiograms performed, 144 revealed congenital heart diseases (9.4%), among these cases 20 were diagnosed with cardiac malposition. Of cases with cardiac malposition, 16 had congenital heart disease, and four had extracardiac malformation. There were six cases of isolated dextrocardia, three cases of situs inversus totalis, six cases of situs ambiguous, and one case of situs inversus with isolated levocardia. Of four cases with extracardiac malformations, two cases had mesoposition, one had dextroposition, and one had extreme levoposition. In six cases the autopsy findings were the same as that their prenatal echocardiographic findings. When postnatal echocardiographic results of the remaining cases with cardiac malposition due to congenital heart disease were compared with prenatal diagnoses, the same echocardiographic findings were verified. CONCLUSION The fetal right/left axis must be determined correctly for the accurate diagnosis of cardiac malpositions. Therefore, we recommend that Cordes technique provides a simple and reliable determination of the fetal right/left axis and fetal situs.