49,XXXXX是一种罕见的染色体病,其发病率未详。现已报道了22个病例。49,XXXXX的女患具有与这种染色体异常相关的典型临床特征,故称“5X综合征”。5X综合征不仅临床上引人注意,而从生物学观点来看,其5个X如何形成更令人感到兴趣。本文描述了一例新病例的临床特征及有关文献回顾,还报道了X五体形成机制的研究结果。患者为6月龄女婴。母龄38岁。父龄 49, XXXXX is a rare chromosomal disease, the incidence is unknown. Has now been reported in 22 cases. 49, XXXXX female patients with this chromosomal abnormalities associated with the typical clinical features, so called “5X syndrome.” 5X syndrome is clinically not only noticeable, but from a biological point of view, it is even more interesting how its 5 X forms. This article describes the clinical features of a case of new cases and related literature review, also reported the results of the study of the formation of X five bodies. The patient is a 6 month old baby girl. The mother is 38 years old. Father’s age