Different Segregation of Chromosomes 5 and 7 in Two Generations and Related Phenotypic Findings

Authors: OSMAN DEMİRHAN, NURDAN TUNALI, ŞEYDA ERDOĞAN, DENİZ TAŞTEMİR, ERDAL TUNÇ

Abstract: Aim: In this study, we aimed to put forth the clinical consequences of rearrangement between chromosomes 5 and 7 observed in one fetus, one newborn infant (siblings) and their parents. Materials and Methods: We performed chromosomal analysis in one fetus, one newborn (siblings) and their parents, applying standard protocols to fetal blood, amniotic fluid and peripheral blood samples. We performed both prenatal and postnatal karyotyping in the newborn infant. Results: We described rearrangements related to chromosomes 5 and 7 in these individuals. We found that the curetted fetus and newborn infant were carriers of unbalanced and balanced rearrangements, respectively. We also found that the mother was a carrier of derivative chromosome 5 with [46,XX,der(5)t(5:7)(p15p11)] karyotype. The prenatal and postnatal karyotypes of the newborn infant confirmed an apparently identical nonreciprocal translocation between chromosomes 5 and 7, the same rearrangement as we found in the mother. We also found that the curetted fetus was carrier of derivative chromosome 5, [46,XY,der(5)t(5:7)(p15p11)mat]. The der(5) contained a complete short arm of chromosome 7. Otherwise both chromosomes 7 appeared normal. The fetus had malformations consistent with trisomy 7p as a result of familial derivative 5. However, the lung findings have not been reported before. Conclusions: Karyotype analysis should be routinely performed in parents of partial trisomy patients and would be beneficial in identifying parents who clearly have a significant recurrence risk for abnormal offspring.

Keywords: Fetus, karyotyping, translocation, derivative chromosome 5

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