PubMedID: 29350657 Hypoparathyroidism (HPT) is a rare disease with leading symptoms of hypocalcemia, associated with high serum phosphorus levels and absent or inappropriately low levels of parathyroid hormone (PTH). In patients with thalassemias it is mainly attributed to transfusional iron overload, and suboptimal iron chelation therapy. The main objectives of this survey were to provide data on the prevalence, demographic and clinical features of HPT in thalassemia major (TM) and intermedia (TI) patients living in different countries, and to assess its impact in clinical medical practice. A questionnaire was sent to all Thalassemia Centres participating to the International Network of Clinicians for Endocrinopathies in Thalassemia and Adolescence 436 V. De Sanctis, A.T. Soliman, D. Canatan, et al.Medicine (ICET-A) Network.Seventeen centers, treating a total of 3023 TM and 739 TI patients, participated to the study. HPT was reported in 206 (6.8%) TM patients and 33 (4.4%) TI patients. In general, ages ranged from 10.5 to 57 years for the TM group and from 20 to 54 years for the TI group. Of the 206 TM patients and 33 TI patients with HPT, 117 (48.9%) had a serum ferritin level >2.500 ng/ml (54.3% TM and 15.1% TI patients) at the last observation. Hypocalcemia varied in its clinical presentation from an asymptomatic biochemical abnormality to a life-threatening condition, requiring hospitalization. Calcium and vitamin D metabolites are currently the cornerstone of therapy in HPT. In TM patients, HPT was preceded or followed by other endocrine and non-endocrine complications. Growth retardation and hypogonadism were the most common complications (53.3% and 67.4%, respectively). Although endocrine complications were more common in patients with TM, non-transfused or infrequently transfused patients with TI suffered a similar spectrum of complications but at a lower rate than their regularly transfused counterparts. In conclusion, although a large international registry would help to better define the prevalence, comorbidities and best treatment of HPT, through the result of this survey we hope to give a clearer understanding of the burden of this disease and its unmet needs. HPT requires lifelong therapy with vitamin D or metabolites and is often associated with complications and comorbidities.Therefore, it is important for endocrinologists and other physicians, who care for these patients, to be aware of recent advances of this disorder. © Mattioli 1885. BC Children’s Hospital Foundation Agricultural University of Athens Ain Shams University Sultan Qaboos University King Abdulaziz University Ministry of Health University College London Alexandria University Shiraz University of Medical Sciences Sultan Qaboos University Princess Grace Foundation-USA 1 Pediatric and Adolescent Outpatient Clinic, Quisisana Hospital, Ferrara, Italy; 2 Department of Pediatrics, Division of Endocrinology, Alexandria University Children’s Hospital, Alexandria, Egypt; 3 Director of Thalassemia Diagnosis Center of Mediterranean Blood Diseases Foundation, Antalya, Turkey; 4 Department of Pediatrics, Ain Shams University, Cairo, Egypt; 5 Hematology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; 6 Department of Haematology, College of Medicine and Health Sciences, Sultan Qaboos University, Sultanate of Oman; 7 King Abdullah University Hospital, Amman, Jordan; 8 Thalassemia Unit, Nicosia, Cyprus; 9 Division of Pediatric and Adolescent Endocrinology, Paedi Center for Specialized Pediatrics, St. George’s University Medical School at the University of Nicosia, Cyprus; 10 Department of Endocrinology, Whittington Hospital, University College London, London, UK; 11 Professor, Pediatric Hemato-Oncology, Christian Medical College and Hospital, Ludhiana, Punjab, India; 12 Department of Pediatrics, Dayanand Medical College & Hospital Ludhiana, Ludhiana, India; 13 Çukurova University, Medical Faculty, Department of Pediatric Hematology, Adana, Turkey; 14 Department of Pediatrics, Endocrinology Unit, Alexandria University Children’s Hospital, Egypt and Child Health Department, Sultan Qaboos University Hospital, Muscat, Sultanate of Oman; 15 Head of Pediatric Endocrine Unit, Department of Child Health, Sultan Qaboos University Hospital, Al-Khoud, Sultanate of Oman; 16 Varna Expert Center for Coagulopathies and Rare Anemias,Varna, Bulgaria; 17 Department of Paediatrics, University Malaya Medical Center, Malaysia; 18 National Center for Cancer Care and Research, Medical Oncology Hematology Section HMC, Doha, Qatar; 19 Endocrinology and Metabolism Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; 20 Princess Rahma Teaching Hospital, Amman, Jordan; 21 Thalassemia Unit, Maternal and Child Department, Garibaldi Hospital, Catania, Italy; 22 Department of Haematology, Thalassaemia and Prenatal Diagnosis Regional Center, Pugliese-Ciaccio Hospital, Catanzaro, Italy; 23 Department of Paediatrics, Pugliese-Ciaccio Hospital, Catanzaro, Italy; 24 Thalassemia Unit, Umberto 1° Hospital, Siracusa, Italy; 25 Primary Health Care, Ministry of Health, Alexandria, Egypt; 26 Department of Pediatrics, Hematology Unit, Faculty of Medicine, University of Alexandria, Egypt and Child Health Department, Sultan Qaboos University Hospital, Muscat, Oman; 27 Head, Division of Pediatric Hematology Oncology, Deputy Chair of Hematology and Head, Section of Hematology Research Lab, King Fahd Medical Research Center, Department of Hematology Faculty of Medicine, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia; 28 Emeritus Director in Pediatrics, Children’s Hospital “Santobono-Pausilipon”, Naples, Italy; 29 Pediatric Hematology Unit, Child Health Department, Sultan Qaboos University Hospital, Muscat, Oman and Department of Pediatrics, Alexandria University Children’s Hospital, Egypt; 30 Department of Pediatrics, Ain Shams University, Cairo, Egypt; 31 First Department of Paediatrics, University of Athens, Athens, Greece