Monossomia em mosaico do cromossomo 13: um relato de caso

Abstract

Chromosome 13 monosomy is a rare cytogenetic event, reported in living offspring only in partial monosomy of chromosome 13 or ring chromosome 13. The main clinical findings related to chromosome 13 aberrations include retinoblastoma, mental and growth deficiency, abnormalities in brain, heart, intestines, and kidneys, and distal limb malformations. The aim of the study was to report a case of a newborn referred to NPR/PUCGoiás/LaGene/Lacen/SES-GO with congenital malformations who received the genetic diagnosis of mosaic chromosome 13 monosomy. Patient was referred from to NPR/PUCGoiás/LaGene/LACEN/SES/GO to perform the karyotype and FISH technique. For the FISH we used the unique sequence probe for the 13q14.2 region and DAPI for counterstaining. Metaphases were not obtained to be analyzed, therefore the analysis by GTG banding was not performed. In 84.8% (123/145) of the analyzed cells, interphasic nuclei were seen with two red fluorescent signals, indicating the presence of two chromosomes 13 and in 15.2% (22/145) of the analyzed nuclei, only one signal was identified representing monosomy of chromosome 13. Thus, the results revealed monosomy of chromosome 13 in mosaic. Mosaic chromosome 13 monosomy was confirmed after the FISH test was performed with the analysis of interphase nuclei. The reported case presented clinical and phenotypic findings similar to Patau's Syndrome and other changes involving chromosome 13. The present study contributed to increase the number of cases described in the scientific literature associated with chromosome 13, allowing a better characterization of complex phenotypes related to chromosome 13.