Chromosome 18p deletion syndrome is a disease caused by the complete or partial deletion of the short arm of chromosome 18, there were few cases reported about the prenatal diagnosis of 18p deletion syndrome. Noninvasive prenatal testing (NIPT) is widely used in the screening of common fetal chromosome aneuploidy. However, the segmental deletions and duplications should also be concerned. Except that some cases had increased nuchal translucency or holoprosencephaly, most of the fetal phenotype of 18p deletion syndrome may not be evident during the pregnancy, 18p deletion syndrome was always accidentally discovered during the prenatal examination. In our case, we found a pure partial monosomy 18p deletion during the confirmation of the result of NIPT by copy number variation sequencing (CNV-Seq). The result of NIPT suggested that there was a partial or complete deletion of X chromosome. The amniotic fluid karyotype was normal, but result of CNV-Seq indicated a 7.56 Mb deletion on the short arm of chromosome 18 but not in the couple, which means the deletion was de novo deletion. Finally, the parents chose to terminate the pregnancy. To our knowledge, this is the first case of prenatal diagnosis of 18p deletion syndrome following NIPT.NIPT combined with ultrasound may be a relatively efficient method to screen chromosome microdeletions especially for the 18p deletion syndrome.

中文翻译：

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无创产前检测18p缺失综合征产前诊断一例

18p染色体缺失综合征是18号染色体短臂完全或部分缺失引起的疾病，18p缺失综合征产前诊断的报道较少。无创产前检测（NIPT）广泛用于筛查常见的胎儿染色体非整倍体。但是，也应该关注片段的删除和重复。18p缺失综合征的胎儿表型除部分病例增加颈部半透明或前脑缺损外，在妊娠期间可能不明显，18p缺失综合征总是在产前检查时意外发现。在我们的案例中，我们在通过拷贝数变异测序 (CNV-Seq) 确认 NIPT 结果的过程中发现了一个纯粹的部分单体 18p 缺失。NIPT结果提示X染色体部分或完全缺失。羊水核型正常，但CNV-Seq结果显示18号染色体短臂有7.56 Mb缺失，而这对夫妇没有，这意味着该缺失是从头缺失。最后，父母选择终止妊娠。据我们所知，这是首例NIPT后18p缺失综合征的产前诊断病例。NIPT联合超声可能是筛查染色体微缺失特别是18p缺失综合征的一种相对有效的方法。父母选择终止妊娠。据我们所知，这是首例NIPT后18p缺失综合征的产前诊断病例。NIPT联合超声可能是筛查染色体微缺失特别是18p缺失综合征的一种相对有效的方法。父母选择终止妊娠。据我们所知，这是首例NIPT后18p缺失综合征的产前诊断病例。NIPT联合超声可能是筛查染色体微缺失特别是18p缺失综合征的一种相对有效的方法。