Fetal Medicine Centre, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong 510630, China.
Fetal Medicine Centre, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
Taiwan J Obstet Gynecol. 2020 Jan;59(1):123-126. doi: 10.1016/j.tjog.2019.11.019.
We present the prenatal diagnosis of a class II 1q21.1 microdeletion in monozygotic (MZ) twins with discordant phenotypes.
A monochorionic diamniotic twin pair presented with discordant ultrasound anomalies; twin A had cardiovascular abnormalities, while twin B did not. No specific complications were noted in the twins during pregnancy. A single nucleotide polymorphism array revealed an identical class II 1q21.1 microdeletion inherited from a phenotypically normal mother and identified the twins as MZ. The deleted region encompassed both the proximal 1q21.1 thrombocytopenia absent radius syndrome region and the distal 1q21.1 recurrent microdeletion region. No other rare copy number variants (CNVs) were identified, and concordance was observed in the CNVs between the twins.
Discordant cardiovascular abnormalities may occur in MZ twins carrying the same class II 1q21.1 microdeletion. Further studies involving discordant MZ twins are needed to determine the modifying factors of the phenotypic heterogeneity of the microdeletion.
我们报告了一例同卵（MZ）双胞胎中存在 II 类 1q21.1 微缺失的产前诊断，其表型不一致。
一对单绒毛膜双羊膜囊的双胞胎表现出不一致的超声异常；双胞胎 A 存在心血管异常，而双胞胎 B 没有。在妊娠期间，双胞胎没有出现任何特定的并发症。单核苷酸多态性微阵列显示，双胞胎从表型正常的母亲那里遗传了相同的 II 类 1q21.1 微缺失，并确定他们为 MZ。缺失区域包含近端 1q21.1 血小板减少性桡骨发育不全综合征区域和远端 1q21.1 复发性微缺失区域。未发现其他罕见的拷贝数变异（CNVs），并且双胞胎之间的 CNVs 存在一致性。
携带相同 II 类 1q21.1 微缺失的 MZ 双胞胎可能出现不一致的心血管异常。需要进一步研究不一致的 MZ 双胞胎，以确定微缺失表型异质性的修饰因子。
