Endocrine Abstracts

Introduction

Turner syndrome (TS) is among the most common chromosomal abnormalities in females, resulting from structural or numeric abnormalities in the X chromosome. Autoimmune disorders, especially thyroid diseases have a high prevalence among these patients. Usually Hashimoto’s thyroiditis (HT) is the most frequent one, whilst the association between this syndrome and Graves’ disease (GD) has been less often reported. Here we report a case of patient with TS who has developed both autoimmune thyroid diseases over the course of her follow-up.

Case report

A 16-year-old female patient was referred to our endocrinology department for symptoms of hyperthyroidism. The patient was diagnosed with TS at the age of 9 when she had consulted for short stature. The diagnosis was confirmed with a karyotype showing a deletion in the short arm of the X chromosome: 46, X del(p12). Shortly after, she developed hypothyroidism and was put under levothyroxine. The patient has a family history of hyperthyroidism in her mother and her uncle. The antithyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-TG) antibodies were negative at the time. At the age of 15, the patient started showing signs of hyperthyroidism such as weight loss, exophthalmia and tachycardia, with a thyroid stimulating hormone (TSH) level at 0.010 mUI/l (0.51 – 4.94 mUI/l). The immunological tests were positive this time with an anti-TPO level at 1300 UI/ml (<60 UI/ml), an anti-TG level at 354.9 UI/ml (<100 UI/ml) and a TSH receptor antibody level at 33 UI/l (<2 UI/l). A neck ultra-sound was performed and showed a hyper vascular goiter. All these exams confirmed the GD in our patient. A treatment with benzyl thiouracil was started for almost a year and the patient thyroid function became normal. At her last consultation, she presented signs of hypothyroidism even after stopping benzyl thiouracil for more than a month and the TSH level was high >100 mUI/l. Therefore, the patient was put again under levothyroxine to eventually achieve normal thyroid function.

Conclusion

Autoimmune thyroid diseases may begin in early childhood in patient with TS, and its prevalence increases with age. HT and GD are caused by two distinct paradigms. Nevertheless, it has been sporadically reported that GD and HT may follow one another in the same individuals, due to a sequential phenotypic conversion from HT to GD, or vice versa. In fact, patients with TS and associated HT were found to be at higher risk of progressing toward GD than the general population.