SAT-354 Isolated Hypoparathyroidism: A Rare Initial Manifestation of Hereditary Hemochromatosis (HH)

Background: We present a case of hypoparathyroidism diagnosed in a patient as initial manifestation of hereditary hemochromatosis. As per our literature search, it is very rarely reported as an isolated abnormality in HH. Case: A 27 year old male with history of seizure disorder, well controlled on Oxcarbazepine, referred for evaluation of chronic hypocalcemia. His PMH includes cerebral palsy, with good functional capacity and mild cognitive impairment. He denied muscle spasm, perioral numbness, bone pain, muscle weakness or fracture. He was taking calcium carbonate 600mg bid and vitamin D 50,000 IU q2monthly. There was no family history of any Ca disorders. Physical exam was unremarkable. Laboratory evaluation revealed Ca levels ranging from 7.6 to 8.5mg/dl with intact PTH values ranging from 11 to 22pg/ml. His ionized calcium was also low. Patient’s 24 hr urinary Ca was 122mg/24hrs. In this case, he did initially have hypomagnesemia and vitamin d deficiency, which could potentially explain low calcium. But even after supplementing Vitamin D and Mg, patient’s Ca remained low. His kidney function was normal. Hemoglobin was in range of 14-15g/dl. To further evaluate the cause of hypoparathyroidism, iron saturation and iron levels were also sent. His iron saturation % was high at 89% with iron level of 286 ug/dl. His ferritin was 224 ng/ml and TIBC was 265 ug/dl. A sample was sent for genetic analysis to rule out hemochromatosis. Homozygous mutations in C282Y gene were found. A diagnosis of hereditary hemochromatosis was made. His other entire hormonal axis was intact. In this case, patient’s hypoparathyroidism is likely an initial manifestation of his HH. Discussion: Hereditary Hemochromatosis (HH) is a genetic disease characterized by an excessive (unregulated) entry of iron into the bloodstream with increased iron deposition in the parenchymal cells of a variety of organs leading to their failure. A defect in the hemochromatosis gene (HFE) is the most common form of HH, also known as the classic form or type 1 HH, where the principal mutation is represented by a substitution of tyrosine for cysteine at position 282 of the HFE gene (C282Y) as seen in our case. According to the genetic forms, the clinical manifestation usually ranges from simple biochemical abnormalities to severe organ damage and disease such as liver cirrhosis, arthritis, DM, cardiomyopathy and hypogonadism. There are reports of hypoparathyroidism from iron overload seen in thalassemia patients and patients who receive long term blood transfusions. In our literature review, this is the first documented case of HH initially manifesting as hypoparathyroidism. As HH is not uncommon in Caucasians, the work up for hemochromatosis as a possible cause of endocrinopathies should be kept in the differential diagnosis. It will help in early diagnosis & treatment which can reverse the effects of the disease leading to better outcomes.