Genetic counseling for a prenatal diagnosis of structural chromosomal abnormality with high-resolution analysis using a single nucleotide polymorphism microarray

A 41-year old pregnant woman underwent amniocentesis to conduct a conventional karyotyping analysis: the analysis reported an abnormal karyotype: 46,XY,add(9) (p24). Chromosomal microarray analysis (CMA) is utilized in prenatal diagnoses. A single nucleotide polymorphism microarray revealed a male fetus with balanced chromosomal translocations on 9p and balanced chromosomal rearrangements, but another chromosomal abnormality was detected. The fetus had microduplication. The child was born as a phenotypically normal male. CMA is a simple and informative procedure for prenatal genetic diagnosis. CMA is the detection of chromosomal variants of unknown clinical significance; therefore, genetic counseling is important during prenatal genetic testing.