Parental balanced reciprocal translocations can result in partial aneuploidy in the offspring due to unbalanced meiotic segregation during gametogenesis. Herein, we report the phenotypic and cytogenetic characterization in a 9-day-old male child with partial trisomy of chromosome 4. Karyotyping of the proband and parents was performed along with multicolor fluorescence in situ hybridization (mFISH) of paternal chromosomes. Conventional cytogenetic analysis by karyotyping showed 47,XY,der(18),t(4;18)(q26;q22),+4 in proband, and the paternal karyotype was found as 47,XY,der(18),t(4;18)(q26;q22). mFISH analysis on paternal chromosomal preparations confirmed both region and origin of the balanced translocation. In this study, karyotyping helped us to identify both numerical and structural anomalies in the proband, and mFISH helped us to confirm our cytogenetic findings. Therefore, cytogenetic screening of both partners is recommended before pregnancy to rule out or confirm the presence of any numerical or structural anomaly in one, both, or none of the partners.
Keywords: Balanced translocation; karyotyping; multicolor fluorescence in situ hybridization; omphalocele.