[Contiguous gene deletion syndrome in Xp21: an unusual form of presentation]. / Síndrome de deleción de genes contiguos en Xp21: una forma inusual de presentación.

INTRODUCTION: We report a case of an infant where the association of Duchenne's muscular dystrophy (DMD) and pseudohypertriglyceridaemia led to the diagnosis of contiguous gene deletion syndrome in Xp21. CASE REPORT: A 7-month-old male infant who was referred due to psychomotor retardation. The examination revealed pronounced axial hypotonia. Lab findings showed high levels of muscular enzymes with creatine phosphokinase levels of 12,829 IU/L, together with high blood levels of triglycerides. Electromyogram findings were consistent with myopathic compromise. The genetic study for dystrophinopathies revealed the existence of a deletion in the dystrophin gene. Further lab findings identified high glycerol concentrations both in blood and in urine that were compatible with a glycerol kinase deficiency. The genetic study confirmed the existence of a deletion in Xp21 of the genes responsible for DMD, the glycerol kinase deficiency, the congenital adrenal hypoplasia (gene DAX1) and mental retardation (gene IL1RAPL1). CONCLUSIONS: In infants and small children with myopathic compromise, increased levels of creatine phosphokinase and pseudohypertriglyceridaemia it is essential to take into account contiguous gene deletion syndrome in Xp21 to be able to prevent and treat the metabolic complications arising from adrenal hypoplasia.

[Microsatellite analysis in exfoliated cells from urinary sediment. Its utility for the detection of bladder cancer. Comparison with urinary cytology]. / Análisis de microsatélites en células exfoliadas del sedimento urinario. Su utilidad para la detección del cáncer vesical. Estudio comparativo con citología urinaria.

INTRODUCTION: Taking into account the precocity of the genetic alterations in the carcinogenesis of the bladder tumors, the valuation of these changes at a level of 9p 21-22 by means of microsatellite markers could be useful for the diagnostic and follow-up. PURPOSE: To evaluate the use of microsatellite markers and the utility of loss of heterozigosity (LOH) and microsatellite instability (MSI) in exfoliated cells from urine sediment. This observation offers the possibility of tumor detection by examining the DNA of urinary sediment. MATERIALS AND METHODS: We amplified with PCR the DNA of urine and blood samples from 160 patients with bladder cancer. We analysed LOH/MSI in cells from urinary sediment using four microsatellite markers of 9p 21-22 (D9S747-D9S171-D9S162-IFNA) and one from chromosome 4 (D4S243). The urinary cytology was used as comparative method and histological examination of tissue obtained by transurethral resection (TUR) as reference diagnostic. We calculated the sensitivity and specificity of this method and if there was some correlation between stage and grade tumoral. RESULTS: We could use 150 samples correctly. In 111 samples we found LOH/MSI (sensitivity 74%). The cytology was positive only in 60 patients (sensitivity 40%). We found a bigger number of microsatellite alterations (AM) in superficial tumors (sensibility 77.3% vs. 28.8% for the cytology) and these were significant when comparing tumors GI-II vs. GIII (MSI p < 0.001--LOH p < 0.004). The marker with more sensibility was D4S243 with 40%. One patient with prostate carcinoma and another one with chronic cystitis gave false positive results. CONCLUSIONS: The study of LOH/MSI in bladder tumors with 5 microsatellites markers, according to our results showed a sensibility of 74%. The biggest number in LOH/MSI was found in superficial tumors and GI-GII tumors. Although we cannot discard the cystoscopy study in the diagnostic and follow-up, the sensitivity of the urine cytology is better and could be one alternative diagnostic as a non-invasive procedure.

[Microsatellite analysis of the 3p13-p25 region in renal cell carcinoma in humans]. / Análisis de microsatélites de la región 3p13-p25 en el carcinoma de células renales en humanos.

INTRODUCTION & OBJECTIVES: Interstitial and terminal deletions of different regions of the chromosome 3 have been associated with the development of human nonpapillary renal cell carcinomas. We performed a microsatellite analysis at the region 3p13-p25 to study the role of the short arm of chromosome 3 in the pathogenesis of Renal Cell Carcinomas. MATERIAL & METHODS: Renal tumor specimens and normal kidney tissue from 57 patients were obtained after radical nephrectomy and immediately snap-frozen. Blood samples were also obtained from each patient, immediately processsed and used as normal DNA. To detect allelic loss, we used 8 microsatellite markers covering the region 3p13-p25. Genetic alterations have been correlated with histology, nuclear grade, pathological stage and stromal cell infiltration. RESULTS: A total of 41 cases (71.9%) were clear cell renal cell carcinomas (CCRCC), 7 (12.3%) were chromophobe renal cell carcinomas, 5 (8.8%) were papillary renal cell carcinomas, and 4 (7%) oncocytic tumors. Microsatellite analysis showed loss of heterozigosity (LOH) in 73.2% of the CCRCCs, and in none of the remaining histologic types. Terminal deletions were detected in 53.3% of the nonpapillary RCCs with LOH, and the remaining nonpapillary RCCs showed multiple interstitial deletions (46.6%). A common region of deletion in 3p14.2 has been observed. Due to contamination with normal DNA, when stromal cell infiltration increases, less losses of heterozigosity are detected. We did not find a correlation between LOH at 3p and the nuclear grade, nor between LOH at 3p and the pathological stage. CONCLUSIONS: 1. Microsatellite analysis of LOH at 3p can be used for the differential diagnosis of renal tumors. 2. The evidence of multiple interstitial deletions in a great number of nonpapillary RCCs suggests that more than one gene should be involved in the development of nonpapillary RCC, and already present in early stages of oncogenesis. 3. The common region of deletion 3p14.2 suggests the presence of unstable sequences of DNA that play an important role in the pathogenesis of nonpapillary RCC. 4. LOH at 3p in most nonpapillary RCCs irrespective of the grade and stage, proves that these molecular alterations do not mark a more aggressive behaviour of the tumor.

[Genetic study of six chromophobic renal carcinomas]. / Estudio genético de 6 carcinomas renales cromófobos.

OBJECTIVES: To determine the role of tumor suppressor genes p53 and von Hippel-Lindau (VHL), and the specific loss of chromosomes 1, 2, 3, 6, 10, 13, 17 and 21 in the pathogenesis of Chromophobe Renal Cell Carcinomas (CrRCC). MATERIAL & METHODS: Renal tumor specimens and normal kidney tissue from 6 patients affected of CrRCC were obtained after radical nephrectomy and immediately snap-frozen. PCR-SSCP analysis for mutations of p53 (exons 5-8) and VHL genes was performed in all cases. All of the positive cases in SSCP analysis were further characterized by direct sequencing. Inactivation by VHL methylation were searched by Southern blot analysis. Microsatellite analysis using several markers covering both arms of chromosomes 1, 2, 6, 10, 13 and 17, as well as 3p and 21q, was performed to investigate specific loss of these chromosomes. RESULTS: Mutations of p53 were detected in 2 (33%) of the 6 CrRCCs, showing both tumors loss of heterocigosity (LOH) on 17p. VHL mutations and inactivation by methylation were not detected in any tumor. In 5 (83.3%) of the 6 CrRCCs, microsatellite analysis showed LOH at every informative marker on all the regions tested except 3p. Retention of heterozigosity on 3p was present in all cases. CONCLUSIONS: Mutations of p53 in CrRCCs are more frequent (33% in our series) than in clear cell renal cell carcinomas (< 2% in most series). Despite 65-75% of clear cell RCCs show VHL mutations (60%) and inactivation by methylation (5-20%), no CrRCC in our series showed these alterations. LOH in the specific chromosomes tested (1, 2, 6, 10, 13, 17 and 21) confirm cytogenetic findings that characterize CrRCCs (specific combinations of multiple chromosomal losses). Our results, similar to those reported by other authors, confirm that CrRCC is not only a histologic fenotype, but also a distinctive genotype from other RCCs. The specific combination of chromosomal losses allows a quick and easy diagnostic of this kind of neoplasms with a simple technique of microsatellite analysis.

Análisis de microsatélites de la región 3p13-p25 en el carcinoma de células renales en humanos / Microsatellite analysis of the 3p13-p25 regions in renal cell carcinoma in humans

INTRODUCCIÓN Y OBJETIVOS: En el desarrollo del carcinoma de células renales no papilar (Carcinoma Renal Convencional-CRC) se han implicado deleciones terminales e intersticiales de diversas regiones del 3p. Se ha realizado un análisis de microsatélites en la región 3p13-p25 para estudiar el papel del brazo corto del cromosoma 3 en la patogénesis del Carcinoma de Células Renales (CCR).MATERIAL Y MÉT ODOS: Se obtuvieron muestras de las piezas de nefrectomía de 57 pacientes afectos de tumor renal. Los controles normales de DNA constitucional lo constituyeron las muestras de riñón sano y sangre periférica de cada paciente. La valoración de la pérdida de heterocigosidad (LOH) se determinó mediante 8 marcadores localizados en 3p13-p25. Las alteraciones genéticas se han correlacionado con la histología, grado nuclear, estadio patológico e infiltración celular estromal.RESULTADOS: Un total de 41 casos (71,9 por ciento) correspondieron a carcinomas renales de células claras o convencionales (CRC), 7 (12,3 por ciento) carcinomas cromófobos, 5 (8.8 por ciento) carcinomas papilares, y 4 (7 por ciento) oncocitomas. El 73.2 por ciento de los CRC mostró LOH, pero ninguno de los restantes tipos histológicos. Deleciones terminales se detectaron en 53,3 por ciento de los CRC con LOH, y el resto mostraron deleciones intersticiales múltiples (46,6 por ciento). La región 3p14.2 presenta una región común de pérdida. Debido a la contaminación con ADN normal, cuando la infiltración celular estromal aumenta. se detectan menor número de LOH. No se ha encontrado asociación de LOH 3p con el grado nuclear, ni con el estadio patológico.CONCLUSIONES: 1. El análisis de microsatélites de LOH en 3p puede ser utilizado para el diagnóstico diferencial de los tumores renales. 2. La evidencia de múltiples deleciones intersticiales en un gran número de CRC sugiere que más de un gen debe estar implicado eu la génesis de esta neoplasia, y que ya debe estar presente en estadios tempranos de la oncogénesis. 3. La región común de pérdida 3p14.2 sugiere la presencia de secuencias inestables de ADN que juegan un papel importante en la patogénesis del CRC. 4. LOH en 3p en la mayoría de los CRC, independientemente del grado y estadio. demuestra que estas alteraciones moleculares no marcan un comportamiento más agresivo del tumor. (AU)

Estudio genetico de 6 carcinomas renales cromófobos / Genetic study of 6 chromophobic renal carcinoma

OBJETIVOS: Determinar el papel del gen Von Hippel-Lindau y p53 en la patogénesis del Carcinoma de Células Renales Cromófobas (CCRCr) y se analiza la frecuencia de pérdidas genéticas en los cromosomas 1, 2, 3p, 6, 10, 13, 17 y 21q. MATERIAL Y MÉTODO: Se obtuvieron especímenes de tumor renal y riñón sano de 6 pacientes afectos de CCRCr directamente de las piezas de nefrectomía radical e inmediatamente fueron congeladas y almacenadas a -80°C. Se practicó un análisis de PCR-SSCP para la identificación de mutaciones en p53 (exones 5-8) y en el gen VHL. Todos los casos positivos en el análisis de SSCP's se caracterizaron posteriormente mediante secuenciación directa. La inactivación por metilación del gen VHL se buscó mediante Southern-blotting. Para investigar pérdidas específicas de diversos cromosomas se practicó análisis de microsatélites utilizando diversos marcadores localizados en ambos brazos de los cromosomas l , 2, 6, 10, 13 y 17, así como en 3p y 21 q. RESULTADOS: No se detectaron mutaciones ni inactivación por metilación del gen VHL en ningún tumor. La mutación del p53 se detectó en 2 (33 por ciento) de los 6 CCRCr, mostrando ambos tumores pérdida de heterocigosidad (LOH) en 17p. En 5 (83,3 por ciento) de los 6 CCRCr, el análisis de microsatélites mostró LOH en todos los marcadores informativos de todas las regiones excepto en 3p. Todos los casos mostraron retención de heterocigosidad en 3p. CONCLUSIONES: Las mutaciones de p53 en CCRCr son más frecuentes (33 por ciento en nuestra serie) que en los carcinomas convencionales o de células claras (< 2 por ciento en la mayoría de las series). A pesar de que el 65-75 por ciento de los carcinomas renales convencionales presenta mutaciones (60 por ciento) e inactivación por metilación (5-20 por ciento) del gen VHL, ningún CCRCr en nuestra serie mostró estas alteraciones. LOH en los cromosomas específicos testados (1. 2, 6, 10, 13, 17 y 21) confirman los hallazgos citogenéticos que caracterizan a los CCRCr. Nuestros resultados confirman que el CCRCr no es sólo un fenotipo histológico, sino también un genotipo distintivo de los otros carcinomas de células renales. La combinación específica de pérdidas cromosómicas permite un rápido y fácil diagnóstico de esta neoplasia con una simple técnica de microsatélites. (AU)