Background: With advances in prenatal diagnostic techniques, chromosomal microdeletions and microduplications have become the focus of prenatal diagnosis. 7q partial monosomy or trisomy due to a deletion or duplication of the 7q end is relatively rare and usually originates from parents carrying a balanced translocation.

Methods: Noninvasive prenatal screening (NIPT) showed a fetus with partial deletion and duplication of chromosome 7q. It was not possible to determine whether the fetus was normal. Methods: Conventional chromosome G-banding and chromosome microarray analysis (CMA) were performed on fetal amniotic fluid samples and parental peripheral blood samples. Methods: The pregnant women were given detailed genetic counseling by clinicians.

Results: The fetal karyotype was 46, XY on conventional G-banding analysis. The CMA test results showed a deletion of approximately 7.8 Mb in the 7q36.1q36.3 region and a duplication of 6.6Mb in the 7q35q36.1 region. The parents' karyotype analysis and CMA results were normal, indicating a new mutation.

Conclusions: CMA molecular diagnostic analysis can effectively detect chromosomal microdeletions or microduplications, clarify the relationship between fetal genotype and clinical phenotype, and provide a reference for prenatal diagnosis of chromosomal microdeletion-duplication syndrome.