ESPE Abstracts

Background: Idiopathic isolated hypoparathyroidism is rare in children. Most often aetiology is autoimmune or genetic.

Objective and hypotheses: To sequence eleven genes (AIRE, CASR, GATA3, GCM2, PCLN1, PTH, TBCE, TRPM6, GNAS, PRKAR1A, PDE4D) associated with hypoparathyroidism in a child with isolated hypoparathyroidism (IHPT) in order to find a specific gene alteration in IHPT.

Method: We systematically sequenced the 11 genes associated with hypoparathyroidism. A total of 1321 genomic regions comprising 246 158 bp were captured with use of custom-designed SureSelect kit (Agilent, Santa Clara, CA, USA). To search structural mutations (e.g., gene deletion and duplication) including the 11 hypoparathyroidism-related genes, we performed aCGH (Agilent Technologies).

Results: This 8 year girl was referred for first seizures with loss of consciousness. She also had headache and vomiting, without papilledema. The height and intelligence were normal. There was no mucocutaneous candidiasis or cataracts. The serum calcium level is low (1.57 mmol/l (normal 2.10–2.55)), and the phosphorus level elevated (3.76 mmol/l (normal 0.85–2.15 mmol/l)). Blood levels of ionized calcium was low (0.65 μmol/l), magnesium normal (0.7 mmol/l (normal 0.7–1.0). Urine calcium excretion was low. The serum alkaline phosphatase level is age-appropriate, 1,25[OH]₂D₃ was not measured, while blood magnesium was normal. Levels of intact PTH were low (<3.0 (normal 10.0–69.0 pg/ml) on an immunometric assay). Radiograph of the wrist was normal. CT scans revealed calcifications in the basal ganglia. TORCH and ultrasound of the kidneys were uneventful. Calcitriol and calcium were recommended.

Conclusion: Idiopathic IHPT is rare in childhood. Although no alteration in eleven IHPT related genes was found, further follow-up is needed to elucidate the genetic and/or autoimmune etiology of IPPT in this child.