[Genetic analysis of a fetus with mosaicism of 13q inversion duplication].

Objective: To report on a case of mosaicism 13q inversion duplication, analyze its mechanism, and discuss the correlation between its genotype and phenotype.

Methods: Amniotic fluid and umbilical cord blood were collected at 23 and 32 weeks of gestation, respectively. Combined with G-banding chromosome karyotyping analysis, single nucleotide polymorphism array (SNP-array) and fluorescence in situ hybridization (FISH) were used to confirm the result.

Results: The karyotype of the fetus was determined as 47,XY,+inv dup(13)(q14.3q34)/46,XY. After careful counseling, the couple decided to continue with the pregnancy, and had given birth to a boy at 40 weeks' gestation. Except for a red plaque (hemangioma) on the nose bridge, no obvious abnormality (intelligence to be evaluated) was discovered.

Conclusion: To provide reference for clinical genetic counseling and risk assessment, the location and proportion of new centromere formation should be fully considered in the case of mosaicism 13q inversion duplication.