Wilson Patrick L, Goodman Jean Ricci, Smith Katie M, Wagner Andrew F
Section of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
J Reprod Med. 2009 Jun;54(6):401-3.
Anencephaly occurs in 1.4-4.7 per 10,000 deliveries and is thought to result from failed closure of the anterior neuropore at 24-26 days post fertilization. Among twins, risk for congenital malformations is greatest among monozygotic twins. Several occurrences of twin pairs being discordant for neural tube defects have been reported: 1 twin affected with anencephaly and co-twin affected with holoprosencephaly, spina bifida or encephalocele, is consistent with a multifactorial pattern of inheritance. We present an instance of monochorionic diamniotic twins concordant for anencephaly.
An 18-year-old, gravida 1, para 0, Caucasian woman presented with monochorionic diamniotic twin gestation at 22 weeks. Prenatal ultrasound identified polyhydramnios, anencephaly, ventricular septal defect and suspected rocker-bottom feet in twin A. Twin B was identified as anencephalic, with left renal agenesis and spinal distortion visualized on ultrasound. Postnatal cytogenetic evaluations of placenta, umbilical cord blood and fetal skin samples from both twins revealed 46,XX karyotypes.
A rare case of a monochorionic diamniotic gestation concordant for anencephaly is presented. Previously published reports of concordant twin anencephaly have postulated a possible autosomal recessive or multifactorial mode of inheritance. Subsequent pregnancies with anencephaly or other open neural tube defects would indicate a mendelian process.
无脑儿的发生率为每10000例分娩中有1.4 - 4.7例，被认为是由于受精后24 - 26天前神经孔闭合失败所致。在双胞胎中，先天性畸形的风险在单卵双胞胎中最高。已有多例双胞胎神经管缺陷不一致的报道：1个双胞胎患无脑儿，另一个双胞胎患全前脑畸形、脊柱裂或脑膨出，这与多因素遗传模式一致。我们报告1例单绒毛膜双羊膜囊双胞胎均患无脑儿的病例。
一名18岁、初孕、未产的白人女性，孕22周时诊断为单绒毛膜双羊膜囊双胎妊娠。产前超声检查发现双胎A羊水过多、无脑儿、室间隔缺损并疑似摇椅样足。双胎B也被诊断为无脑儿，超声检查显示左肾缺如和脊柱畸形。对双胞胎的胎盘、脐带血和胎儿皮肤样本进行产后细胞遗传学评估，结果均显示核型为46,XX。
本文报告1例罕见的单绒毛膜双羊膜囊双胎妊娠均患无脑儿的病例。先前发表的关于双胎无脑儿一致的报道推测可能为常染色体隐性遗传或多因素遗传模式。随后再次妊娠出现无脑儿或其他开放性神经管缺陷将提示孟德尔遗传过程。
