A comparison of the clinical and cytogenetic findings in nine patients with a ring (X) cell line and 16 45,X patients.

In this study, the clinical, IQ, and cytogenetic findings in nine Turner's syndrome patients with a ring (X) cell line are compared with those in 16 patients in whom only a 45,X cell line could be found. The ring (X) patients lacked many of the "classic" Turner's syndrome features and the majority were not karyotyped until after the age of 11, usually because of pubertal failure. They also showed a reduction in IQ of 11 points compared with the 45,X group. Some ring (X) patients show characteristic facial features including a broad nose with anteverted nostrils, prominent philtrum, long palpebral fissures, and a wide mouth with a thin upper lip. Neither the physical features nor the IQ are related to the parental origin of the chromosome error. In the majority of cases the ring (X) chromosome was late replicating but XIST activity is being studied further.