Turner Syndrome and the Thyroid Function-A Systematic and Critical Review

Abstract

Turner syndrome (TS) is associated with thyroid disorders. Since the rate of thyroid disease among patients with this syndrome is significantly higher as compared to the general population, it seems vital to explore this particular area. This systematic and critical review was performed to evaluate thyroid function and autoimmunity in patients with Turner syndrome. Four databases were searched: PubMed, Scopus, Google Scholar, and Cochrane Library from the onset of the study to July 2024. Two independent researchers manually searched databases for the following keywords: "Turner syndrome", "anti-TPO", "anti-Tg", "autoimmune thyroid disorders", "TSH", and "hypothyroidism", which were entered into the search engine in isolation, as well as in combinations. Criteria incorporating information on thyroid-stimulating hormone (TSH), triiodothyronine (total-TT3), and thyroxine (free and total-fT4, TT4) concentrations among patients and control groups were also included. Thyroid diseases are common in patients with Turner syndrome. Women with TS present both higher TSH levels and positive thyroid antibodies concentrations. Typical thyroid ultrasound heterogeneity with a hypogenic or mixed echopattern was also observed. As a result, it is essential to monitor thyroid hormone levels in this group, in order to detect hypothyroidism earlier and initiate appropriate replacement therapy. Thyroid diseases in women with TS may remain underdiagnosed for a number of years, due to the lack of screening. Therefore, the authors suggest a thyroid screening regimen for TS patients, which allows for early detection of the disease and implementation of treatment.

Keywords: Turner syndrome; anti-thyroid antibodies; autoimmunity; hypothyroidism; thyroid function; thyroid hormones.

Figure 1

The percentage of patients with positive thyroid antibodies. The study group for the purpose of our review was calculated by means of adding the study groups from the relevant sources [26,30,31,32,33,34,35]; the same procedure was adopted for the control group. We excluded source [36] from this analysis, due to the lack of information regarding patients with positive thyroid antibodies. In total, 806 patients were included from the study groups (patients with TS), where in 342 cases, positive thyroid antibodies were found. The control group consisted of 887 individuals in total, among whom 180 presented with positive thyroid antibodies. The sources [26,30,31,32,33,34,35] do not provide a division according to antibody types, and hence there is no information if the anti-TPO and/or anti-Tg were elevated in patients. Table 4 presents levels of thyroid antibodies.

Figure 2

Proposed thyroid management for patients with TS.

Figure 3

PRISMA flowchart. We performed a PubMed, Scopus, Cochrane Library, and Google Scholar search throughout July 2024. The oldest articles were also significant in order to obtain as much data as possible. Search terms included “Turner syndrome”, “anti-TPO”, “anti-Tg”, “autoimmune thyroid disorders”, “TSH”, and “hypothyroidism”, used as isolated keywords and in combination. The flowchart was performed in order to obtain information about thyroid function in women with Turner syndrome.

Figure 4

Bias assessment using version 2 of the Cochrane risk-of-bias tool for randomized trials (RoB 2) [26,30,31,32,33,34,35,36].