Tubulopathy and pancytopaenia with normal pancreatic function: a variant of Pearson syndrome.

Out of a series of 30 French patients with Pearson syndrome, we report on two patients with an atypical presentation, which include growth deficiency, pancytopaenia, tubulopathy and absence of exocrine pancreas dysfunction. Patient 1, a 4-year-old boy with a past history of pancytopaenia and transient metabolic acidosis at 13 months of age, presented at 2(1/2) years of age with severe tubulopathy of de Toni-Debré-Fanconi type, growth retardation, metabolic lactic acidosis and mild cytolysis. Despite normal exocrine pancreatic function, study of mitochondrial DNA revealed a 3.5 kb deletion. Patient 2 had a personal history of pancytopaenia requiring blood transfusions at 11 months of age and presented with severe intractable proximal and distal tubulopathy at 2 years of age. Exocrine pancreatic deficiency could not be evidenced and post-mortem studies revealed a 4.9 kb deletion of the mitochondrial DNA. A review of the literature revealed three patients presenting with Pearson syndrome and tubulopathy with normal pancreatic function and highlights delay in diagnosis in those three patients. The series of 30 French patients with Pearson syndrome also revealed that tubulopathy was present in 7/30 cases (23%), with variable outcome. In conclusion, Pearson syndrome should be screened for in children presenting with the association of growth retardation, anaemia/pancytopaenia, lactic acidosis and tubulopathy, even in the absence of exocrine pancreatic deficiency.

Bifidez pieloureteral proximal derecha incompleta y triplicidad pieloureteral proximal izquierda incompleta / Right proximal partial bifidus pelvis and ureter and left partial proximal pyeloureteral triplicity

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Tumores renales de la infancia y adolescencia asociados a anomalías cromosómicas / Renal tumors of childhood and adolescence associated with chromosomal anomalies

El riñón pediátrico es sitio frecuente de tumores que exhiben alteraciones cromosómicas características. El más común es el nefroblastoma o tumor de Wilms (TW) que se asocia con dos loci: 11p13 (WT1) y 11p15 (WT2 ó BWS), este último ligado también del síndrome de Beckwith-Wiedemann. Otros dos genes que parecen estar implicados son WT3 y WT4; además, dos anomalías específicas (adquisición 1q y deleción 22) se han correlacionado de manera independiente con un peor pronóstico en TW. Otras neoplasias con rearreglos cromosómicos, tales como los carcinomas renales (CRs), son mucho menos frecuentes en niños (entre el 1.8 y el 6.3% de todos los tumores renales malignos). Entre estos, se han identificado 'CRs con translocación' que afectan el locus Xp11, siendo los dos tipos más importantes t(X;1), y t(X;17). El nefroma mesoblástico congénito (NMC) es un tumor renal de recién nacidos y lactantes. Los NMCs de la variedad celular se caracterizan por una translocación específica t(12;15)(p13;q25), misma que se encuentra también en los fibrosarcomas congénitos extrarenales, y que permite establecer una correspondencia genética entre estos dos tumores (NMC y fibrosarcoma congénito). Los tumores rabdoides (TR) del riñón son neoplasias muy infrecuentes y muy agresivas, que aparecen con una edad promedio de 11 meses. Al menos 50% de los TRs muestran anormalidades en el gen hSNF5/INI1, situado en el locus 22q11.2. Este gen probablemente está involucrado en la modulación transcripcional de otros genes, tales como el oncogen c-Myc, y de la vía de transducción de la proteína RB-retinoblastoma

The pediatric kidney is a common site for tumors carrying specific chomosomal alterations. The most common of these is the nephroblastoma or Wilms tumor (WT), which is associated with anomalies in two loci: 11p13 and 11p15, the latter also linked to Beckwith-Wiedemann syndrome. Two other genes that seem to be implicated are WT3 and WT4. In addition, 1q gains or 22 deletions have been shown to independently be associated with a worst prognosis in WTs. Other neoplasms with chromosomal rearrangements, such as Renal Cell carcinomas (CRs) are much less frequent in children (between 1.8 and 6.3 % of all malignant renal tumors). Among these, the 'translocation renal carcinomas' have been identified involving the locus Xp11 with two main types of translocations: t(X;1), and t(X;17). Congenital mesoblastic nephroma (NMC) is a renal tumor affecting newborns and young infants. NMCs of the cellular type feature a specific translocation t(12;15)(p13;q25), which is also present in congenital fibrosarcomas outside of the kidney. These findings have led to conclude that these two tumors (NMC and congenital fibrosarcoma) are genetically equivalent. Rhabdoid tumors (TRs) of the kidney are very rare and aggressive neoplasms that appear with a mean age of 11 months. At least 50% of these TRs carry abnormalities in the hSNF5/INI1 gene, at 22q11.2. This gene is probably involved in transcriptional modulation of other genes such as the oncogene c-Myc, and also of the retinoblastoma protein RB signaling pathway

Different phenotypes of dysplastic kidney in obstructive uropathy in fetal lambs.

PURPOSE: The cause of cyst production in renal dysplasia is uncertain. The authors hypothesized that different patterns of renal dysplasia result from variations in the timing and site of the urinary tract obstruction. METHODS: The authors operated on fetal lambs at 50 and 60 days' gestation. Male lambs underwent urethral and urachal ligation and female lambs unilateral ureteric ligation. They were delivered by cesarean section at 145 days' gestation and killed. RESULTS: Of 12 lambs operated on at 50 days' gestation, 4 survived. Of 26 lambs operated on at 60 days, 21 survived. The authors identified 3 types of dysplastic kidneys. Type A, fibrotic kidneys (2.2 g) with no cysts and interstitial fibrosis. There were reduced numbers of proximal tubules, but distal tubules and collecting ducts persisted. (50-day obstruction, n = 5 kidneys); type B, Sponge-like kidneys (37g): these had large cysts with minimal interstitial fibrosis. (87% of 60-day uretheral and urachal ligation model n = 12 kidneys); Type C, Small kidneys (4.8 g) with no large cysts (60-day Ureteric ligation model n = 7 kidneys). CONCLUSION: The authors produced 3 different types of renal dysplasia by creating urinary tract obstruction at different sites and gestational ages.