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Down Syndrome Resulting from a Rare non-Robertsonian Translocation t(11;21)(p13;q22)

2021; FACULDADE DE MEDICINA DE SÃO JOSÉ DO RIO PRETO; Volume: 28; Issue: 1 Linguagem: Inglês

10.17696/2318-3691.28.1.2021.1795

2318-3691

Dante Bruno Avanso Rosan, Priscila L. Dourado, Andréa Engracia Ruiz, Valéria C.C. Ferrarezi Da Silva, Cristina Benitez Vendrame, Andréa B. Carvalho-Salles, Brasilina De F. Mafei, Agnes Cristina Fett‐Conte,

RNA modifications and cancer

Introduction: Down syndrome (DS) is a common genetic disorder, occurring in approximately 1 in 700 births. It results from an extra copy (triplication) of the whole or part of the long arm of chromosome 21 caused by different cytogenetic alterations: free trisomy, Robertsonian translocations, mosaicism, duplication of the critical region and other structural rearrangements. Non-Robertsonian chromosome translocations are very rare events with few cases reported. Case Report: We identified the non-Robertsonian translocation t(11;21)(p13;q22) and two chromosomes 21 in a female child referred with a clinical diagnosis of trisomy 21. The infant developed the transient myeloproliferative disorder at 17 months. Cytogenetic analysis was performed in lymphocytes and bone marrow metaphases according to standard procedure - G banding and fluorescence in situ hybridization. The karyotype study of the parents revealed that her phenotypically normal mother carries the same reciprocal translocation. Conclusion: This is the second report of the translocation t(11;21)(p13;q22), the first one resulting in DS. This description expands knowledge about cytogenetic variability in the etiology of DS. Future studies are needed to investigate the long-term clinical effects of the trisomy 21 associated with t(11;21)(p13;q22).