Primary hypoparathyroidism in childhood: clinical and etiological spectrum in a tertiary referral center from southeastern Türkiye

Background. Primary hypoparathyroidism is a rare endocrine disorder in childhood; data on its clinical and etiological spectrum in pediatric populations remain limited. We aimed to characterize the clinical, biochemical, etiological, and therapeutic spectrum of pediatric primary hypoparathyroidism at a tertiary center in Southeastern Türkiye. Methods. A retrospective, single-center observational cohort study was conducted between January 2016 and January 2026. Medical records of 27 children (0–18 years) with nonsurgical primary hypoparathyroidism were reviewed. The diagnosis required persistent hypocalcemia with hyperphosphatemia and inappropriately low or normal intact parathyroid hormone on at least two measurements, in the absence of secondary causes. Demographic, clinical, biochemical, imaging, genetic testing (fluorescence in situ hybridization/multiplex ligation-dependent probe amplification for 22q11.2; targeted sequencing for candidate genes), and treatment data were collected. Results. Median age at diagnosis was 3 months (interquartile range: 1.6–111 months; range: 3 days–17 years); 9 patients (33.3%) were diagnosed in the neonatal period. Seizures were the most frequent presenting feature in 12 patients (44.4%). A specific etiological diagnosis was established in 11 patients (40.7%): DiGeorge syndrome in 5 (18.5%), Kenny–Caffey syndrome type 1 in 3 (11.1%), Sanjad–Sakati syndrome in 1 (3.7%), autoimmune polyglandular syndrome type 1 in 1 (3.7%), and autosomal dominant hypocalcemia type 1 due to an activating calcium-sensing receptor (CASR) mutation in 1 (3.7%). Twenty-four patients (88.9%) received combined oral calcium and calcitriol therapy. Two patients (7.4%) died from sepsis. Conclusions. In this Southeastern Turkish pediatric cohort, DiGeorge syndrome and tubulin-specific chaperone E gene (TBCE) -related disorders were the most prominent identified etiologies; the enrichment of TBCE-related disorders likely reflects regional consanguinity and Arab-origin demographics. An integrated diagnostic approach combining clinical, biochemical, and genetic evaluation is essential in similar populations. Prospective multicenter studies with systematic genetic testing are warranted.