[Familial occurrence of Turner syndrome].

The authors report a family in which a woman with the mosaic Turner karyotype 45,X/46,X,r(X) transmitted the ring (X) chromosome to the second daughter and transmitted the X-derived chromosome to the first daughter. The mother had normal fertility with three documented pregnancies and conceptions occurred without any hormonal therapy. Her first pregnancy ended with spontaneous abortion, while the second pregnancy resulted in a 45,X/46,X,+mar female with ovarian failure and the third pregnancy resulted in a 45,X/46,X,r(X) female. The nature of the ring chromosome was confirmed by conventional cytogenetic technics. A small marker chromosome was identified as an X-derived chromosome by fluorescent in situ hibridisation (FISH).