Marlet Lyvia, Alix Eudeline, Till Marianne, Raskin-Champion Fabienne, Attia Jocelyne, Boggio Dominique, Sanlaville Damien, Schluth-Bolard Caroline
Laboratoire de Cytogénétique Constitutionnelle, Service de Génétique, Centre de Biologie et de Pathologie Est, Hospices Civils de Lyon, Bron, France.
Cytogenet Genome Res. 2017;153(3):117-124. doi: 10.1159/000485392. Epub 2017 Dec 22.
We report on a prenatally diagnosed unusual case of inverted terminal duplication of the short arm of chromosome 2, leading to interstitial telomeric sequences (ITSs) and partial trisomy 2p. To our knowledge, there are only 4 further cases of pure partial trisomy 2p reported prenatally. Here, the mother was referred at 22 weeks of gestation for isolated fetal congenital heart malformation at ultrasound. The karyotype of amniotic fluid cells displayed a large duplication of the short arm of chromosome 2 that was further investigated by array-CGH, which detected a 1-copy gain of 43.75 Mb in chromosome 2 at 2p21p25.3. FISH confirmed the presence of an inverted duplication in the short arm of chromosome 2 involving the region 2p21pter and revealed the presence of ITSs at the breakpoint in chromosome 2p21. This report contributes to the prenatal description of the syndrome. We also discuss the possible mechanisms leading to this duplication and the formation of ITSs which are rarely described in constitutional rearrangements.
我们报告了一例产前诊断的2号染色体短臂倒置末端重复的罕见病例，该病例导致了间质端粒序列（ITSs）和2p部分三体。据我们所知，产前仅另有4例纯2p部分三体的病例报道。在此病例中，母亲在妊娠22周时因超声检查发现孤立性胎儿先天性心脏畸形而前来就诊。羊水细胞的核型显示2号染色体短臂存在大片段重复，通过比较基因组杂交芯片（array-CGH）进一步研究发现，在2p21p25.3区域2号染色体有43.75 Mb的1拷贝增益。荧光原位杂交（FISH）证实2号染色体短臂存在涉及2p21pter区域的倒置重复，并揭示在2p21染色体的断点处存在ITSs。本报告有助于该综合征的产前描述。我们还讨论了导致这种重复及ITSs形成的可能机制，而ITSs在染色体结构重排中很少被描述。
