Prevalence of renal malformation in Turner syndrome.

The presence of renal malformation was evaluated in 43 patients with Turner syndrome (TS) and compared with the karyotype in each case; 28 patients (65%) had a mosaic karyotype and the other 15 (35%) had only 45,X metaphases. Renal malformations characteristic of TS were found in 24% of the complete sample group. Of the 15 cases of pure 45,X karyotype, 8 (53%) had abnormal renal findings, while these were found in only 2 of the 28 mosaic cases (7.1%). The probability of this distribution having occurred by chance is P < 0.05. More than 50% of girls with TS are said to have a renal anomaly. In this study renal malformations were found in 25% of the sample group. A significantly greater association of renal malformation was found with monosomy 45,X than with mosaicism. As mosaicism occurs in up to 60% of all girls with TS, the lower figure reported here represents a truer prevalence than that quoted in older series, where the figures quoted applied only to the 45,X syndrome.