ACTA ENDOCRINOLOGICA (BUC)

Denosumab,a monoclonal IgG2 antibody directed against RANK-L,is used as a neoadjuvant therapy for inoperable or metastatic giant cell tumor of bone. Many side effects like as hypocalcemia during treatment and rarely severe hypercalcemia especially in children after discontinuation of denosumab occurred. The unpredictable onset and recurrent episodes of severe hypercalcemia increase the duration of hospitalization and the risk of complications. Persistent hypercalcemia and difficulties in management have prompted the search for different more effective therapeutic options. Objectives. To share our experience with the use of oral bisphosphonate in acute and long-term therapy of severe hypercalcemia following high-dose denosumab therapy and to review the literature on this subject Case. We report the management of a case of severe hypercalcemia that developed 4 months after the completion of 18-month denosumab treatment in a 9-year-old girl who was followed up with a giant cell bone tumor for 6 years. Based on an evaluation aiming to determine etiology, hypercalcemia was considered as "rebound-linked" upon denosumab discontinuation. Severe hypercalcemia attacks recurring with an interval of 2 weeks were treated with IV bisphosphonate, but when mild hypercalcemia developed again, treatment with 70 mg per week of oral bisphosphonate was planned. After the second dose of alendronate, the calcium level always remained below 10.5 mg/dl. In the 14-month follow-up, no hypercalcemia attack was observed again. Results. Rebound hypercalcemia can occur as an unpredictable recurrent episode at any time after denosumab cessation. Thus, the patient should be closely monitored especially in childhood due to rapid bone cycle. In longterm follow-up, oral biphosphonates can be used effectively to reduce hospitalization time and the management of especially life-threatening recurrent attacks.

Background. NR5A1 [Steroidogenic factor 1 (SF1)] is a nuclear receptor that is essential for the development of gonads and adrenal glands as well as the establishment of steroidogenesis in these organs. The clinical findings of the mutations of NR5A1 gene in 46, XY individuals are variable. Virilization at puberty can be seen in some of the 46, XY children who have a female phenotype and are raised as female. A girl aged 13 years and 10 months old was brought by the family for deepening of her voice. On physical examination, her breast development was Tanner stage 2, axillary hair (+) and pubic hair was Tanner stage 4. She had labioscrotal fusion and 4.4 cm phallus (External Masculinisation Score was 6). Hypergonadotropic hypogonadism, low AMH and high testosterone levels were detected in laboratory tests. Uterus was not visualized in pelvic ultrasonography. Karyotype analysis was reported as 46, XY. Sequence analysis of the NR5A1 gene revealed a novel heterozygote c.1075_1089del (p.Leu359_Leu363del) variant. The patient was raised as a female and oestrogen replacement was started following gonadectomy. Conclusion. It should be kept in mind that virilization may develop at puberty in individuals with 46, XY disorder of sexual development due to NR5A1 mutation.

Objectives. Maternal antibodies in cases of chronic autoimmune thyroiditis may be transferred to the baby via the transplacental route, leading to transient hyperthyroidism or hypothyroidism. The development of hyperthyroidism in one sibling and hypothyroidism in the other, however, is an extremely rare condition. We present two siblings, one with transient neonatal hyperthyroidism and the other with transient neonatal hypothyroidism, born to a euthyroid mother who was being treated for Hashimoto's thyroiditis. Case Presentation. Case 1: A term male baby was evaluated due to tachycardia, high fT4 and low TSH. Following a diagnosis of Neonatal thyrotoxicosis, the patient was started on methimazole and propranolol treatments. The doses were gradually reduced and methimazole was stopped in the 5th month of treatment. Case 2: A male baby was referred with elevated TSH identified in the neonatal screening program, with TSH >100 mIU/L and fT4 7.5 pmol/l (N: 12-22) found in a venous blood sample. The patient was started on 50 μg/day LT4, which was gradually decreased and stopped when the baby was 5.5 months old. Conclusion. It should be kept in mind that antibodies may change character in mothers with autoimmune thyroiditis, and may cause different clinical pictures in babies in different pregnancies.