Objective: To explore the genetic basis for a fetus with club foot detected upon mid-pregnancy ultrasonography.
Methods: Amniotic fluid of the fetus and peripheral blood samples of its parents were collected and subjected to G-banding karyotype analysis and copy number variation sequencing (CNV-seq). The result was verified by fluorescence in situ hybridization (FISH).
Results: The fetus and its parents all had a normal karyotype. CNV-seq analysis revealed that the fetus has harbored a 23.12 Mb on chromosome 5 and a 21.46 Mb duplication on chromosome 7. FISH assay has verified that its mother has carried a cryptic t(5;7)(p14.3;q33) translocation.
Conclusion: CNV-seq combined with FISH can effectively detect cryptic chromosome aberrations, and can help to reduce severe birth defects and provide a basis for prenatal genetic counseling.