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[Application of single nucleotide polymorphism-based array analysis for prenatal diagnosis of a fetus with de novo derivative chromosome].

OBJECTIVE
To analyze a fetus with increased nuchal translucency and nuchal fold, and to assess the recurrence risk for her family and provide a basis for prenatal diagnosis.


METHODS
G-banded karyotyping and single nucleotide polymorphism-based array (SNP-Array) analysis were used to analyze the fetus and her parents.


RESULTS
SNP-Array analysis has detected a 41.04 Mb duplication at Xp22.33p11.4 and a 30.51 Mb duplication at 13q31.3q34 in the fetus. G-banding karyotyping indicated that the fetus had a karyotype of 46,X,der(X)(13qter-13q31::Xp11.4-Xp22.3::Xp22.3-Xqter). Her parents had normal results for both G-banding karyotyping and SNP-Array analysis, suggesting that the fetus has carried a de novo derivative chromosome X.


CONCLUSION
SNP-Array combined with G-banding karyotyping is helpful to confirm the composition and connection type of de novo derivative chromosome, which can improve the accuracy of diagnosis and is valuable for the evaluation of recurrence risk.