ESPE Abstracts

Background: Hyperphosphatemic familial tumoral calcinosis (HFTC) is a condition characterized by hyperphosphatemia and abnormal deposit of phosphate and calcium most often around the hips, shoulders and elbows and rarely in the brain.

Case presentation: A four-year-old-girl from Arabian origin was referred to the regional paediatric endocrine clinic from the Orthopedics Team due to: recurrent calcinosis of the right calcaneus and incipient left wrist pain. Examination: weight 17.5 kg (SDS 0.19) and height 105 cm (SDS 0.24). General examination unremarkable, in particular no signs of inflammation of joints. No evidence of neurological impairment. Inicial investigations: serum sodium, chloride, potassium and creatinine levels were normal. Serum calcium 9.9 mg/dl (8.1–10.4), phosphorus 8.6 mg/dl (2.7–4.5), magnesium 2.1 mg/dl (1.7–2.5), intact parathyroid hormone 24.2 pg/ml (15–88), and 25-vitamin-D 19 pg/ml (12–54). Random urinary calcium/creatinine ratio 0.015. TmP/GFR 3.9 mg/100 ml. Homozygosity for the mutation c.814_815 insA in the GALNT3 gene was found, which helps to regulate fibroblast growth factor 23 by glycosylation of protein called ppGalNacT3. Diagnosis: hyperphosphatemic familal tumoral calcinosis. Further investigations: no eye abnormalities, no cardiac/coronary calcifications, no pathological features on kidneys ultrasound scan. Head CT scan: bilateral superficial linear cortex brain calcifications. Management: low phosphorus diet and calcium acetate. After treatment optimization, biochemical results: phosphorus 7.8 mg/dl and TRP 98.6%. Clinical evolution: new joints pain. At this point the patient received treatment with sevelamer carbonate, which binds phosphate from food in the digestive tract. No side-effects were reported. Progress: serum phosphorus level decreased and the patient experienced an improvement of her symtoms.

Conclusion: i) In cases of calcinosis in paediatric patients, phosphorus and calcium metabolism assesment is recommended as part of initial approach in order to avoid future complications. ii) Management of hyperphosphatemia is complex in hyperphosphatemic familial tumoral calcinosis. This case suggests sevelamer carbonate as an option to decrease serum phosphate levels in the setting fail in previous known therapeutic options.