Sabbagh Quentin, Larrieux Marion, Schneider Anouck, Theze Corinne, Vincent Marie-Claire, Coubes Christine, Puechberty Jacques, Renard Sarah, Koenig Michel, Pellestor Franck, Cossée Mireille, Gatinois Vincent
Montpellier University, Centre de Référence « Anomalies du Développement et Syndromes Malformatifs », ERN-ITHACA, Department of Clinical Genetics, University Hospital of Montpellier, Montpellier, France.
Montpellier University, Molecular Diagnostic Laboratory, University Hospital of Montpellier, Montpellier, France.
Eur J Hum Genet. 2024 Jul 16. doi: 10.1038/s41431-024-01665-0.
Single-gene copy number variants (CNVs) limited to placenta although rarely identified may have clinical implications. We describe a pregnant woman referred for chorionic villus sampling due to increased fetal nuchal translucency. Incident intragenic deletion of Duchenne muscular dystrophy (DMD) gene, affecting exons 56 and 57, was identified in a male fetus in ~23-30% of placental cells by chromosomal microarray and confirmed using multiplex ligation-dependent probe amplification (MLPA). Rapid aneuploidy testing showed normal results and the deletion was not detected in the mother. Subsequent analyses on amniotic cells yielded a normal DMD gene result, corroborating the confined placental nature of the mosaicism. Hence, this report emphasizes the importance of conducting amniocentesis following detection of mosaicism for single gene CNVs on chorionic villi, in order to preclude confined placental mosaicism (CPM). As far as we know, this report marks only the second documented situation of CPM involving an intragenic DMD deletion.
尽管很少被发现，但仅限于胎盘的单基因拷贝数变异（CNV）可能具有临床意义。我们描述了一名因胎儿颈部透明带增厚而转诊进行绒毛取样的孕妇。通过染色体微阵列在约23%-30%的胎盘细胞中鉴定出杜氏肌营养不良症（DMD）基因的内含子缺失，该缺失影响外显子56和57，并使用多重连接依赖探针扩增（MLPA）进行了确认。快速非整倍体检测结果正常，且在母亲体内未检测到该缺失。随后对羊水细胞的分析得出DMD基因结果正常，证实了这种嵌合体的胎盘局限性。因此，本报告强调了在绒毛膜绒毛上检测到单基因CNV嵌合体后进行羊膜穿刺术的重要性，以排除局限性胎盘嵌合体（CPM）。据我们所知，本报告仅记录了第二例涉及DMD基因内含子缺失的CPM情况。
