Department of Obstetrics and Gynecology, Prenatal Diagnostic Service, Guastalla Civil Hospital, Azienda Unità Sanitaria Locale Reggio Emilia, Reggio Emilia, Italy.
Preconceptional and Prenatal Diagnostic Center, Istituto di Ricerca a Carettere Clinico Scientifico Galliera Hospital, Genoa, Italy.
Taiwan J Obstet Gynecol. 2014 Dec;53(4):592-7. doi: 10.1016/j.tjog.2014.01.005.
Trisomy 9 is a rare chromosomal abnormality usually associated with first-trimester miscarriage; few fetuses survive until the second trimester. We report two new cases of complete trisomy 9 that both present unusual phenotypic associations, and we analyze the genetic pathway involved in this chromosomal abnormality.
The first fetus investigated showed Dandy-Walker malformation, cleft lip, and cleft palate) at the second trimester scan. Cardiovascular abnormalities were characterized by a right-sided, U-shaped aortic arch associated with a ventricular septal defect (VSD). Symmetrical intrauterine growth restriction and multicystic dysplastic kidney disease were associated findings. The second fetus showed a dysmorphic face, bilateral cleft lip, hypoplastic corpus callosum, and a Dandy-Walker malformation. Postmortem examination revealed cardiovascular abnormalities such as persistent left superior vena cava draining into the coronary sinus, membranous ventricular septal defect, overriding aorta, pulmonary valve with two cusps and three sinuses, and the origin of the left subclavian artery distal to the junction of ductus arteriosus and aortic arch.
Complete trisomy 9 may result in a wide spectrum of congenital abnormalities, and the presented case series contributes further details on the phenotype of this rare aneuploidy.
三体 9 是一种罕见的染色体异常，通常与妊娠早期流产有关；很少有胎儿能存活到妊娠中期。我们报告了两例完全三体 9 的新病例，它们都呈现出不寻常的表型关联，并分析了这种染色体异常涉及的遗传途径。
第一个被研究的胎儿在妊娠中期扫描时表现为 Dandy-Walker 畸形、唇裂和腭裂）。心血管异常的特征是右侧 U 形主动脉弓与室间隔缺损（VSD）相关。对称的宫内生长受限和多囊性发育不良性肾病是相关的发现。第二个胎儿表现为畸形的脸、双侧唇裂、胼胝体发育不全和 Dandy-Walker 畸形。尸检显示心血管异常，如永存左上腔静脉引流至冠状窦、膜性室间隔缺损、主动脉瓣上型、肺动脉瓣有两个瓣叶和三个窦、左锁骨下动脉起源于动脉导管和主动脉弓的交界处远端。
完全三体 9 可能导致广泛的先天性异常，本病例系列进一步详细介绍了这种罕见的非整倍体的表型。
