[Genetic analysis and prenatal diagnosis for a pregnant woman with an unbalanced t(1;2), t(6;7) translocation and intellectual disability].

OBJECTIVE: To provide genetic analysis for a pregnant woman with chromosomal translocations and intellectual disability, and to provide prenatal diagnosis for her fetus.

METHODS: Routine G-banding was performed to analyze the karyotypes of the woman and her fetus. Copy number variants were determined with array comparative genomic hybridization (array-CGH).

RESULTS: The pregnant woman has carried an apparently balanced translocation involving chromosomes 1, 2, 6 and 7, with a karyotype of 46, XX, t(1;2) (p22;p23), t(6;7) (q21;p15). The karyotype of her fetus was ascertained as 46, XY, t(6;7) (q21;p15) mat. Array-CGH has detected a 4 Mb microdeletion at 6q22.1-q22.31 (115 311 507-119 332 956) in both individuals. As the 6q22.1-q22.31 microdeletion may be associated with the main clinical manifestations of the woman, the family decided to terminate the pregnancy. The fetus was male and appeared to have no obvious abnormality.

CONCLUSION: Prenatal diagnosis for pregnant women with translocations and mental retardation is a challenging task. Combined application of cytogenetic analysis and array-CGH may facilitate the diagnosis and genetic counseling.