Prenatal diagnosis of a rare case with de novo partial 21q(21q22.1→ qter) trisomy syndrome and absent nasal bone / 中华医学遗传学杂志

ABSTRACT

OBJECTIVE@#To carry out prenatal diagnosis for a fetus with absent nasal bone by using cytogenetic and molecular techniques.@*METHODS@#Chromosomal karyotyping, single nucleotide polymorphism array (SNP-array) and fluorescence in situ hybridization (FISH) assays were applied for the diagnoses. Peripheral blood samples were also taken from the parents for chromosomal karyotyping and FISH analysis.@*RESULTS@#The fetus was found to have a 46,XX,add(21)(p11.2) karyotype, and SNP-array has revealed a 11.3 Mb duplication at 21q22.12q22.3 (hg19 36 762 648-48 093 361), which was confirmed by FISH. Both parents were found to be normal by chromosomal karyotyping and FISH analysis. The fetus was ultimately found to have a karyotype of 46,XX,der(21)t(21;21)(p11.2;q22.1), resulting a de novo partial trisomy of 21q22.1.@*CONCLUSION@#Combined use of various techniques has enabled accurate prenatal diagnosis and genetic counseling for the fetus.