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

Omori Sarabi, Sadaf; Karimzad Hagh, Javad; Behrend, Claudia; Mohseni, Seyed Behrooz; Ansari Dezfouli, Mitra; Rashidi, Seyed Khalil; Omrani, Mir Davood

doi:10.29252/ibj.24.1.60

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