Kamel Abidi

Primary hyperoxaluria in infants.

The infantile form of primary hyperoxaluria type-1 (PH-1) is characterized by a rapid progression to the end-stage renal disease (ESRD) due to both increased oxalate load and reduced glomerular filtration rate. In the literature, data on this form are limited. The purpose of this study is to analyze retrospectively the clinical, biological, and radiological features of children who were diagnosed with PH-1 during the 1(st) year of life. We reviewed the records of all children with PH-1 diagnosed and followed-up at our department between January 1995 and December 2013. Among them, only infants younger than 12 months of age were retrospectively enrolled in the study. Fourteen infants with the median age of two months were enrolled in the study. At diagnosis, 11 patients had ESRD. All patients had nephrocalcinosis and two of them had calculi. The diagnosis was established in nine patients on the basis of the positive family history of PH-1, bilateral nephrocalcinosis, and quantitative crystalluria. In four patients, the diagnosis was made with molecular analysis of DNA. Kidney biopsy contributed to the diagnosis in one patient. During follow-up, two patients were pyridoxine sensitive and preserved renal function. Seven among 11 patients who had ESRD died, four patients are currently undergoing peritoneal dialysis. Children with infantile PH and ESRD are at high risk of early death. Peritoneal dialysis is not a treatment of choice. Combined liver-kidney transplantation is mandatory.

A novel mutation in the AGXT gene causing primary hyperoxaluria type I: genotype–phenotype correlation

Primary hyperoxaluria type I (PH1) is an autosomal recessive metabolic disorder caused by inherited mutations in the AGXT gene encoding liver peroxisomal alanine : glyoxylate aminotransferase (AGT) which is deficient or mistargeted to mitochondria. PH1 shows considerable phenotypic and genotypic heterogeneity. The incidence and severity of PH1 varies in different geographic regions. DNA samples of the affected members from two unrelated Tunisian families were tested by amplifying and sequencing each of the AGXT exons and intron–exon junctions. We identified a novel frameshift mutation in the AGXT gene, the c.406_410dupACTGC resulting in a truncated protein (p.Gln137Hisfs*19). It is found in homozygous state in two nonconsanguineous unrelated families from Tunisia. These molecular findings provide genotype/phenotype correlations in the intrafamilial phenotypic and permit accurate carrier detection, and prenatal diagnosis. The novel p.Gln137Hisfs*19 mutation detected in our study extend the spectrum of known AGXT gene mutations in Tunisia.

Infantile cystinosis: From dialysis to renal transplantation

Cystinosis is an autosomal recessive, lysosomal storage disease characterised by the accumulation of the amino acid cystine in different organs and tissues. It is a multisystemic disease that can present with renal and extra-renal manifestations. In this report, we present the first case of transplanted nephropathic cystinosis in a Tunisian child. A 4-year-old Tunisian boy born to nonconsanguineous parents, was treated in our medical services in 1990 for cystinosis. Since the age of five months, he developed symptoms of severe weight loss, vomiting, dehydration, and polyuria. He manifested the Toni Debré Fanconi syndrome. Slit lamp examination of the anterior segment of both eyes revealed fine, shiny crystal-like deposits diffusely distributed in the corneal epithelium and the stroma. Our patient had renal failure. At the age of seven, he reached terminal chronic renal failure and was treated with peritoneal dialysis. Hemodialysis was started at the age of nine years. At the age of 13 years, he received a renal transplantation and was started on cysteamine 1999, five months after the renal transplantation. Currently, the patient is 28-year-old. The graft has survived 15 years after the transplantation. Renal functions were stable with a serum creatinine of 123 μmol/L at last follow-up.

HOGA1 Gene Mutations of Primary Hyperoxaluria Type 3 in Tunisian Patients

Primary hyperoxaluria type 3 (PH3) is due to mutations in the recently identified 4‐hydroxy‐2‐oxoglutarate aldolase (HOGA1) gene. PH3 might be the least severe form with a milder phenotype with good preservation of kidney function in most patients. The aim of this study was to report three PH3 cases carrying mutations in HOGA1.

Williams-Beuren syndrome associated with single kidney and nephrocalcinosis: a case report

Williams-Beuren syndrome is a rare neurodevelopmental disorder, characterized by congenital heart defects, abnormal facial features, mental retardation with specific cognitive and behavioral profile, growth hormone deficiency, renal and skeletal anomalies, inguinal hernia, infantile hypercalcaemia. We report a case with Williams-Beuren syndrome associated with a single kidney and nephrocalcinosis complicated by hypercalcaemia. A male infant, aged 20 months presented growth retardation associated with a psychomotor impairment, dysmorphic features and nephrocalcinosis. He had also hypercalciuria and hypercalcemia. Echocardiography was normal. DMSA renal scintigraphy showed a single functioning kidney. The FISH generated one ELN signal in 20 metaphases read and found the presence of ELN deletion, with compatible Williams-Beuren syndrome.

Tuberculosis following kidney transplantation: report of paediatric case

Recipients of solid organ transplantation are, because of immunosuppressive therapy, at high risk to develop opportunistic infections including tuberculosis (TB). The incidence, clinical manifestations, and optimal diagnostic tests of this disease in this population have not been adequately defined. In this paper, we report a case of 13 year-old boy who developed pulmonary tuberculosis following a second renal transplantation from a deceased donor. The described case points diagnostic difficulties of the tuberculosis disease which are due to insidious and non specific clinical presentation. Also, the treatment is delicate because interaction between immunosuppressive drugs and antituberculosis drugs.