Endocrine Abstracts

Introduction: Hyperprolactinemia is a relatively frequent finding. A wide range of conditions can be responsible of this biochemical abnormality. Herein we report a rather rare etiology of hyperprolactinemia which is Turner syndrome (TS).

Methods: Aiming to determine the frequency of hyperprolactinemia in patients with TS, we enrolled a retrospective descriptive study in the department of Endocrinology at the Hedi Chaker Hospital. We included patients who have the cytogenetic confirmation of Turner syndrome and who consulted our department between 1990 and 2021. As for hyperprolactinemia, it is defined as a prolactin level above 25 ng/ml.

Results: The total number of patients in our study was 45. Their mean age of diagnosis was 16 years. Most of them were diagnosed after the age of 10 years (88.9 %). Karyotype analysis revealed the presence of X monosomy in 49 % of cases, mosaicism without structural alterations of X in 31 % and mosaicism with structural variants of the X chromosome in 20 % of cases. Dosage of prolactin was performed in 29 patients with primary amenorrhea. The median prolactin level was 11.7 ng/ml [Q1, Q3: 8.8-16.6 ng/ml]. Four patients had hyperprolactinemia which corresponds to a frequency of 13.8 %. The mean age of these patients was 17.5 years, with extremities ranging from 15 to 21 years. Cytogenetic findings were variable among these patients as one had 45, X, the second had 45, X/46, XX, the third had an Y chromosome and the karyotype of the fourth girl was 46, XX/46, X i(Xq). This latter patient had a positive SRY. As for the mean prolactin level, it was 49.05 ng/ml. The maximum was 60.8 ng/ml. Regarding the etiology of this biochemical abnormality, we excluded hepatic dysfunction, renal insufficiency and hypothyroidism. Drug-induced hyperprolactinemia was also dismissed. A pituitary MRI was performed in two cases and it was normal. The evolution of hyperprolactinemia was marked by its spontaneous regression in two cases: after one year in the first case and after four years in the second. Conversely, the two other patients had persistent hyperprolactinemia.

Conclusion: Hyperprolactinemia is not an exceptional finding in TS. However, gaps remain in our understanding of the pathophysiological mechanisms underlying this abnormality. Therefore, more research is warranted.