Guo Cuixia, Sun Lijuan, Liu Yan, Yan Yousheng, Wang Li, Wang Xinlian, Wu Qingqing
Department of Ultrasound, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Maternal and Child Health Care Hospital, Beijing, 100026, China.
Department of Prenatal Diagnostic Center, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, China.
BMC Pregnancy Childbirth. 2024 Dec 20;24(1):842. doi: 10.1186/s12884-024-07014-9.
Blake's pouch cyst (BPC) is a midline cystic anomaly of the posterior fossa. BPC has been shown to have a risk of aneuploidy prenatally. Copy number variation (CNV) and/or genetic syndromes have been reported in a few prenatal/postnatal cases with BPC. The purpose of this study is to determine the additional value of CNV analysis for prenatal diagnosis and prognosis evaluation of BPC.
We reviewed the sonographic findings and genetic results of BPC diagnosed within 6 years at our center. Patients were classified into the isolated and non-isolated groups based on the prenatal and postnatal imaging. We analyzed the chromosomal abnormalities by conventional karyotype analysis combined with chromosomal microarray analysis (CMA) or CNV sequencing (CNV-seq).
We recruited 467 low-risk fetuses as the control group to establish normal references of vermian area and brainstem-vermis (BV) angle. Prenatal/postnatal MRI or neonatal neurosonography was used as diagnostic criteria. 34 patients were diagnosed as BPC, including 21 (61.8%) patients with non-isolated and 13 (38.2%) with isolated. Twenty-two patients underwent CMA/CNV-seq, among them 14 patients were performed both CMA/CNV-seq and karyotype analysis. Seven (7/22, 31.8%) patients with BPC had chromosomal abnormalities, including 3 (3/22, 13.6%) patients with chromosomal aneuploidy - trisomy 21, 18 and 13, and 4 (4/22, 18.2%) patients had pathogenic CNVs located at 3p, 9p, Xp/Xq and 7p. Anomalies in fetal heart (35.3%), central nervous system (CNS) (26.5%) and limb (14.7%) were the three top anomalies accompanying BPC.
CNV analysis could provide some additional information for prenatal diagnosis and prognosis counseling for patients with non-isolated BPC. And, it adds less value for patients with isolated BPC, however, isolated BPC can be a soft marker for aneuploidy.
布莱克氏囊囊肿（BPC）是后颅窝的一种中线囊性异常。已证明BPC在产前有非整倍体风险。在少数产前/产后BPC病例中报告了拷贝数变异（CNV）和/或遗传综合征。本研究的目的是确定CNV分析对BPC产前诊断和预后评估的附加价值。
我们回顾了本中心6年内诊断为BPC的超声检查结果和基因检测结果。根据产前和产后影像学检查，将患者分为孤立性和非孤立性两组。我们通过传统核型分析结合染色体微阵列分析（CMA）或CNV测序（CNV-seq）分析染色体异常情况。
我们招募了467例低风险胎儿作为对照组，以建立蚓部面积和脑干-蚓部（BV）角的正常参考值。产前/产后MRI或新生儿神经超声检查用作诊断标准。34例患者被诊断为BPC，其中21例（61.8%）为非孤立性，13例（38.2%）为孤立性。22例患者接受了CMA/CNV-seq检测，其中14例患者同时进行了CMA/CNV-seq和核型分析。7例（7/22，31.8%）BPC患者存在染色体异常，其中3例（3/22，13.6%）为染色体非整倍体——21、18和13三体，4例（4/22，18.2%）患者存在位于3p、9p、Xp/Xq和7p的致病性CNV。胎儿心脏（35.3%）、中枢神经系统（CNS）（26.5%）和肢体（14.7%）异常是伴随BPC的三大主要异常。
CNV分析可为非孤立性BPC患者的产前诊断和预后咨询提供一些额外信息。而且，对于孤立性BPC患者，其附加价值较小，然而，孤立性BPC可能是一种非整倍体的软指标。
