1/3. Acrocentric chromosome polymorphisms: beware of cryptic translocations.Cryptic translocations may escape diagnosis, especially when they implicate chromosomal regions that are known to be polymorphic in the human karyotype. We describe a case of postnatal diagnosis of beckwith-wiedemann syndrome (BWS) due to an unbalanced translocation that had not been diagnosed in the fetal karyotype. This first cytogenetic analysis revealed that one chromosome 14 presented as a common acrocentric short arm polymorphism. Further analyses after birth, using C-banding, NOR staining and fluorescence in situ hybridization (FISH) with telomeric probes, revealed that it was the result of an unbalanced de novo t(11;14)(p15;p13) translocation leading to partial 11p trisomy and to BWS. Prenatal cytogenetic management of such apparently inoffensive chromosome markers is discussed.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/3. Microarray detection of a de novo der(X)t(X;11)(q28;p13) in a girl with premature ovarian failure and features of beckwith-wiedemann syndrome.We report an 18-year-old girl with premature ovarian failure (POF), tall stature, and urinary incontinence. Chromosome studies including array comparative genomic hybridization showed that she was the carrier of an unbalanced de novo translocation between the x chromosome and chromosome 11, resulting in partial monosomy Xq and partial trisomy 11p. Microsatellite analysis demonstrated that the patient had paternal duplication of 11p13p15.5, which contributed to some of her features consistent with beckwith-wiedemann syndrome (BWS). The combined phenotype of BWS and POF suggests that the translocated portion of 11p remains active.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
3/3. Molecular analysis of a patient with beckwith-wiedemann syndrome, rhabdomyosarcoma and renal cell carcinoma.We described a patient with beckwith-wiedemann syndrome associated with rhabdomyosarcoma (RMS), and renal cell carcinoma (RCC). Karyotypes of peripheral lymphocytes and RMS cells were normal. dna analyses showed maternal loss of heterozygosity (LOH) at 11p15 region in RMS but not in RCC. The insulin-like growth factor ii gene (IGF2) was found to be expressed at a moderate level in RMS but not in RCC by in situ hybridization. Each of parental allele-derived IGF2 transcript was detected in RCC, while maternal allele-derived transcript was weak in RMS because of maternal LOH. These results suggest that (1) loss of imprinting (LOI) of IGF2 might be responsible for BWS, (2) on the other hand, LOI itself might not induce tumor occurrence in tissues where the control of tissue-specific expression of IGF2 is maintained, (3) increased expression of IGF2 due to maternal loss of a putative controller gene for IGF2 at 11p15 might predispose to sustaining tumorigenic mutations and tumor progression, (4) loss of a putative onco-suppressor gene at 11p15 might induce RMS occurrence. The cause of RCC was thought to be different from that of RMS.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |