[The TRH test in Turner syndrome].
In order to evaluate the functionality of the hypothalamic-hypophyseal-thyroid axis in Turner's syndrome (TS), 27 subjects, aged between 5.1 and 16.1 years old, were studied, 14 of whom were karyotype 45,XO and 13 affected by mosaicism. The TRH test (200 mcg i.v.) was performed in all subjects using a single bolus. TRH titers were assayed in serum samples collected at 0, 15, 30, 60 and 90 minutes, and anti-microsome and anti-thyroglobulin, T4 and T3, were assayed in the basal sample; the latter were also assayed in the blood sample collected at 120 minutes. These results were compared with those obtained using the same test in a group of age- and sex-matched controls. Anti-thyroid antibodies and basal levels of T3 and T4 were within the norm in 26 subjects; a high basal value of TSH was only found in one patient with chromosomic mosaicism with an elevated response to TRH and a high titer of anti-microsomic antibodies. Apart from this no statistically significant differences were found in patients compared to control subjects in relation to TSH values at all stages of the test and between the two groups of TS; no significant results were found in the comparison between the areas below the curves (AUC). On the basis of these results the Authors conclude that it is not possible to reveal alterations in thyroid function attributable to hypothalamic and hypophyseal anomalies in this group of patients either with karyotype 45,XO and mosaicism.