Prenatal diagnosis and clinical evaluation of fetuses with structural X chromosome abnormalities: a ten-year single-center retrospective study

BACKGROUND: Structural X chromosome abnormalities are rare conditions and pose great challenges in prenatal genetic counseling. The present study aimed to identify and investigate the pregnancy outcome of fetuses with X chromosome structural abnormalities in the Chinese population. METHODS: A total of 12 fetuses with X chromosome structural abnormalities were collected from 16,817 individuals who underwent prenatal diagnosis at Quanzhou Women’s and Children’s Hospital. Karyotype and/or chromosomal microarray analysis (CMA) were utilized to detect chromosomal abnormalities. RESULTS: Among the 12 fetuses with structural X chromosome abnormalities, one case had a balanced X; autosome chromosome translocation, the other 11 cases had unbalanced X; autosome or X-Y chromosome rearrangements. Eight subjects performed CMA detection, the CMA result was inconsistent with karyotype analysis result in Case 4, in which an additional 2q37.2q37.3 microduplication observed in the fetus. Finally, the karyotype of Case 4 was described as 46,X, der(X)t(X;2)(q22.3;q37.2). Parental origin verification was performed in 9 of the 12 cases, of which four cases were de novo and five cases inherited from the pregnant women. Prenatal ultrasound examination were available for 8 out of 12 cases, all the fetuses exhibited soft ultrasound abnormalities. CONCLUSION: The present study reports a series of 12 cases with structural X chromosome abnormalities. Our findings suggest that parental verification is valuable for guiding genetic counseling and managing pregnancy outcomes in fetuses with structural X chromosome abnormalities. In addition, CMA would be benefit for investigating the precise chromosome break points detected by karyotype analysis.