ESPE Abstracts

Background: Hypoparathyroidism (HP) is the most common first endocrinopathy in patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome (APECED or APS1), an autosomal recessive condition caused by mutations in the AIRE gene. Treatment of HP has not changed over the decades and parathyroid hormone is used only rarely.

Aim: To describe clinical characteristics and course of HP in a cohort of patients with APECED and evaluate treatment challenges in pediatric patients.

Methods: We collected retrospectively the data concerning diagnosis and treatment of HP in patients with APECED diagnosed in Finland after 1960. Medical histories were reviewed for all required adjustments in calcium and active vitamin D dosing before the age of 18 years. The first year after diagnosis was excluded from the analyses. Serum ionized calcium, plasma phosphate and urine calcium to creatine ratios were measured during normal follow up using fasting blood samples and second void urine samples in patients.

Results: Altogether 29 patients were included in the study; 21 (72%) were females. Median age at diagnosis of HP was 5.77 years (Interquartile range, 4.25–7.66). In 34% of them APECED diagnosis was made before development of HP. Calcium supplement was started at the time of diagnosis in 33% of patients in 1960–1980 (n=12) and in 82% of patients after 1980 (n=17). Based on data on 148 patient years, the mean number of medicine adjustments per year was 5.74. Signs of nephrocalcinosis had been found in five patients (17%) before the age of 18 years. The cohort included six patients who were currently followed at pediatric centers. Their median age was 12.5 years (range, 7.0–16.5 years) and median HP disease duration 8.8 years (range, 0.3–12.9 years). One patient was treated with teriparatide with an infusion pump. In the pediatric subjects the median plasma ionized calcium was 1.12 (range, 1.02–1.25) mmol/l and met the target range of 0.98–1.08 mmol/l in every third of the patients. Median phosphate level was 1.72 (1.25–1.84) mmol/l. Urine calcium to creatine ratio was below 0.7 in 83% of patients.

Conclusions: Treatment of HP with calcium supplements and vitamin-D metabolites requires frequent dose adjustments in patients with APECED and indicates a need for improved treatment modalities.