Rationale: Chromosome deletion/duplication has been reported to be associated with mental disability and dysmorphism according to the accumulated research evidence.
Patient concerns: A 25-year-old woman underwent amniocentesis for cytogenetic and single-nucleotide polymorphism (SNP) array analysis at 18 weeks of gestation due to the increased Down syndrome risk of 1/13.
Diagnoses: The fetal chromosomal analysis revealed a seemingly "normal" chromosomal karyotype, but the SNP array results showed a partial duplication of chromosome 4q34.1q35.2 and a deletion of chromosome 7q34q36.3fluorescence in situ hybridization (FISH) analysis showed that the couple had normal chromosome 4 and 7, whereas there was a partial signal fragment of chromosome 4 attached on the long arm of chromosome 7 for the fetus.
Interventions: The couple finally chose to terminate the pregnancy based on the ultrasonic multiple malformations and the abnormal SNP array results.
Outcomes: The duplicated/deleted segments of the fetus were de novo. Meanwhile, we consider SHH and XRCC2 as good candidate genes, which may, in part, explain the observed abnormalities for the fetus.
Lessons: The combination of SNP array and FISH analysis can give a molecular chromosomal diagnosis, which will offer more clear cytogenetic diagnosis and genetic counseling.