Department of Obstetrics and Gynecology, King Edward Memorial Hospital, and School of Women's and Infants' Health, The University of Western Australia, Perth, Western Australia.
Am J Med Genet A. 2010 Oct;152A(10):2578-87. doi: 10.1002/ajmg.a.33599.
Abnormally formed lower limbs with varying degrees of fusion are the major feature of sirenomelia whereas maldeveloped lower limbs without fusion are found in association with caudal dysgenesis (CD). The relationship between these two entities has been a topic of debate for many years. The presence of a single umbilical artery originating from the abdominal aorta was considered a major feature distinguishing sirenomelia from CD. Based on this finding, the vascular steal theory was put forward as the causative mechanism of sirenomelia. CD and sirenomelia were considered to be two entirely different entities with distinct pathogenic mechanisms. However, it is now clear that a single umbilical artery can be found in some patients of CD and normal umbilical arteries in some patients of sirenomelia. The hypothesis of primary deficiency of caudal mesoderm caused by early developmental disruption suggests that sirenomelia and CD are two ends of a spectrum of maldevelopment of caudal mesoderm. In this paper we report on the clinical and pathological features of 16 patients of CD and 9 patients of sirenomelia from our institution and review the literature. This series of cases is notable for the significant association with neural tube defects, refining the renal and urogenital pathology associated with these conditions, and supporting the concept of a continuum of the disease spectrum.
下肢形态异常，有不同程度的融合，是美人鱼综合征的主要特征，而尾部发育不良（CD）则表现为下肢发育不良而无融合。这两种情况之间的关系多年来一直是争论的话题。单一的脐动脉起源于腹主动脉被认为是将美人鱼综合征与 CD 区分开来的主要特征。基于这一发现，血管盗血理论被提出作为美人鱼综合征的发病机制。CD 和美人鱼综合征被认为是两种完全不同的实体，具有不同的发病机制。然而，现在很清楚，一些 CD 患者存在单一脐动脉，而一些美人鱼综合征患者存在正常脐动脉。早期发育中断导致尾中胚层原发性缺陷的假说表明，美人鱼综合征和 CD 是尾中胚层发育不良的两种极端情况。本文报告了 16 例 CD 和 9 例美人鱼综合征患者的临床和病理特征，并复习了文献。本系列病例的显著特征是与神经管缺陷显著相关，完善了与这些情况相关的肾脏和泌尿生殖系统病理学，并支持疾病谱连续体的概念。
