Characterization of a Rare Mosaicism in Autosomal Translocation of t(5;21) Using Conventional Cytogenetics and FISH Methods

Authors
Sadaf Omori Sarabi 1
Javad Karimzad Hagh 1
Claudia Behrend 2
Seyed Behrooz Mohseni 1
Mitra Ansari Dezfouli 3
Seyed Khalil Rashidi 4
Mir Davood Omrani 5
1 Paresh Pathobiology and Genetics Laboratory, Tehran, Iran
2 Praxisgem für Medizinische Genetik, Düsseldorf, Germany
3 Department of Neuroscience and Addiction Studies, School of Advanced Technologies in Medicines, Tehran University of Medical Science, Tehran, Iran
4 Biotechnology Research Center, Semnan University of Medical Science, Semnan, Iran
5 Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Science, Tehran, Iran
10.29252/ibj.24.1.60
Abstract
Background: Mosaicism of a normal cell population and an unbalanced autosomal chromosome rearrangement is rarely seen. If the abnormal cell line contributes to a minor part of soma, the phenotype is expected to be normal. Case Report: We report a 29-year-old woman who had balance chromosomal translocation of 46,XX,t(5;21) with a two-year-old affected girl, characterized by mental retardation, dystrophia, hearing impartment, and dysphagia. Methods and Results: Cytogenetic investigation revealed a low mosaic unbalanced translocation of 46,XX,t(5;21)/ 46,XX, which was confirmed by fluorescence in situ hybridization analysis. Studying 200 metaphases and interphases of peripheral blood sample revealed 70% partial monosomy of 21q22 and partial trisomy of 5q(35.3) and 30% of normal pattern. Conclusion: In rare cases such as this study, parents with balanced translocation with no phenotypes may lead to a mosaic unbalanced translocation with abnormal phenotypes in offspring, which underscores the need for prenatal karyotyping and genetics counseling.
Keywords
Partial monosomy 21q
Translocation t(5
21)
Unbalanced autosomal chromosome translocation mosaicism