Neuman W L, Ponto K, Farber R A, Shangold G A
Department of Obstetrics and Gynecology, University of Chicago Pritzker School of Medicine, Illinois.
Obstet Gynecol. 1990 Mar;75(3 Pt 2):479-83.
Although the overall incidence of ectopic gestation has been rising over the past 30 years, unilateral twin tubal gestation is still a relatively rare event. In the 93 cases reported to date, zygosity determined solely by subjective observations of the fetuses indicated monozygosity in more than 95%. We report a case of unilateral twin tubal gestation in which zygosity of the twins was determined by using DNA probes that detect restriction fragment length polymorphisms. We used six human DNA probes and M13 phage DNA to compare the genotypes of the twins. Three of the six human probes and the M13 probe showed differences, proving that these twins were dizygotic. We speculate that many of the unilateral ectopic twins who were thought to be monozygotic may actually have been dizygotic.
尽管在过去30年里异位妊娠的总体发生率一直在上升，但单侧双输卵管妊娠仍然是相对罕见的情况。在迄今为止报告的93例病例中，仅通过对胎儿的主观观察确定的合子性显示，超过95%为单合子性。我们报告一例单侧双输卵管妊娠病例，其中通过使用检测限制性片段长度多态性的DNA探针确定双胞胎的合子性。我们使用六种人类DNA探针和M13噬菌体DNA来比较双胞胎的基因型。六种人类探针中的三种以及M13探针显示出差异，证明这些双胞胎是双合子性的。我们推测，许多被认为是单合子性的单侧异位双胞胎实际上可能是双合子性的。
