Endocrine Abstracts

Introduction: Hypocalcaemia is present in half of the patients with 22q11.2 deletion syndrome (DiGeorge-velocardiofacial syndrome). Most of these cases are diagnosed during childhood.

Case report: A 56-year-old man was evaluated for symptomatic hypocalcaemia after undergoing a left nephrectomy because of renal tumour. He had paraesthesia around his mouth and hands and Trousseau’s sign. His past medical history included high blood pressure, type 2 diabetes, dyslipidaemia and chronic obstructive pulmonary disease. He mentioned a hypocalcaemia episode 10 years ago, frequent bronchitis at childhood and learning difficulties. Blood tests showed hypocalcaemia of 6.2 mg/dl (NV: 8.4–10.2) hypoalbuminaemia of 29.7g/l, (35–50 g/l), corrected calcium of 7.08 mg/dl, hyperphosphataemia of 4.8 mg/dl (2.3–4.7) and normal magnesium. Parathyroid hormone (PTH) was 11 pg/ml (15–88), 25-hydroxy vitamin D 16 pg/ml (>30) and 1.25-dihydroxy vitamin D 20.1 pg/ml (26.1–95). Thyroid function was normal. The electrocardiogram showed no prolonged QT interval. Endovenous and oral calcium and calcitriol were initiated, with normalization of calcium levels. Based on hypocalcaemia secondary to primary hypoparathyroidism anti-parathyroid antibodies and anti-calcium sensor receptor were requested. Due to childhood medical history and dysmorphic phenotype (hooded eyelid, bulbous nasal tip) a genetic test of 22q11.2 deletion was made. Anti-parathyroid antibodies were negative, anti-calcium sensor receptor antibodies finally were not made and the genetic test confirmed the diagnosis, so more tests were made in the outpatient clinic. Treatment at discharge was oral calcium and calcitriol. Echocardiography was normal. Densitometry revealed no bone mass loss. Immunologic studies showed a mild disturbance of cellular immunity. He received genetic advice of affected offspring.

Conclusions: It is important to classify hypocalcaemia diagnosed at any age, and especially hypocalcaemia due to genetic syndromes, as in our case, due to the 50% risk of an affected offspring.