Zhu Xiaofan, Lam Doris Yuk Man, Chau Matthew Hoi Kin, Xue Shuwen, Dai Peng, Zhao Ganye, Cao Ye, Cheung Sunny Wai Hung, Kwok Yvonne Ka Yin, Choy Kwong Wai, Kong Xiangdong, Leung Tak Yeung
Genetics and Prenatal Diagnosis Center, Department of Obstetrics and Gynaecology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China.
Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong, China.
Genes (Basel). 2020 Dec 24;12(1):11. doi: 10.3390/genes12010011.
Trisomy 7 is the most frequently observed type of rare autosomal trisomies in genome-wide non-invasive prenatal screening (NIPS). Currently, the clinical significance of trisomy 7 NIPS-positive results is still unknown. We reviewed two independent cohorts from two laboratories where similar NIPS metrics were applied. A total of 70,441 singleton cases who underwent genome-wide NIPS were analyzed, among which 39 pregnancies were positive for trisomy 7, yielding a screen-positive rate of 0.055% (39/70,441). There were 28 cases with invasive testing results available; the positive predictive value (PPV) was 3.6% (1/28). We then searched the published NIPS studies to generate a large cohort of 437,873 pregnancies and identified 247 cases (0.056%) that were screened positive for trisomy 7. The overall PPV was 3.4% (4/118) in the combined data. The presence of uniparental disomy 7 was not detected in the NIPS trisomy 7-positive pregnancies with normal fetal karyotype. Among the 85 cases with pregnancy outcome available in combined data, 88.2% were normal live births, 14.1% had intrauterine growth restriction, preterm birth or low birth weight, 3.5% presented with ultrasound abnormality, and no fetal loss was observed. Our data provide valuable information for counseling and management of trisomy 7-positive NIPS pregnancies.
7号染色体三体是全基因组无创产前筛查（NIPS）中最常观察到的罕见常染色体三体类型。目前，7号染色体三体NIPS阳性结果的临床意义仍不清楚。我们回顾了来自两个实验室的两个独立队列，这两个实验室应用了相似的NIPS指标。总共分析了70441例接受全基因组NIPS的单胎妊娠病例，其中39例妊娠7号染色体三体呈阳性，筛查阳性率为0.055%（39/70441）。有28例可获得侵入性检测结果；阳性预测值（PPV）为3.6%（1/28）。然后，我们检索已发表的NIPS研究，以生成一个包含437873例妊娠的大型队列，并确定了247例（0.056%）7号染色体三体筛查呈阳性的病例。合并数据中的总体PPV为3.4%（4/118）。在胎儿核型正常的NIPS 7号染色体三体阳性妊娠中未检测到单亲二体7的存在。在合并数据中可获得妊娠结局的85例病例中，88.2%为正常活产，14.1%有宫内生长受限、早产或低出生体重，3.5%有超声异常，未观察到胎儿丢失。我们的数据为7号染色体三体阳性NIPS妊娠的咨询和管理提供了有价值的信息。
