ODP588 A Rare Case Of Infantile Transient Psuedohypoparathyrodism

Abstract Background Pseudohypoparathyroidism (PHP) is a heterogeneous group of disorders in which resistance to parathyroid hormone (PTH) in the proximal renal tubules leads to hypocalcemia, hyperphosphatemia, and impaired 1,25(OH)2 vitamin D production. Clinical Case A 2-month-old child presented with history of recurrent focal seizures since last 10 days. During the first episode, the child was treated with anti- convulsant by paediatrician. Five days later she again developed focal seizures, this time the child was evaluated and serum calcium was 5.6 mg/dl (normal, 8.6-10.2 mg/dl), phosphorus 7.5 mg/dL (normal, 4. 0-7. 0 mg/dL), and magnesium 2. 0 mg/dL (normal 1.8-2.4 mg/dL). In view of symptomatic hypocalcemia, she was treated with I. V. 10% calcium gluconate and oral calcifediol (800 IU/day). The child was seizure free but still had hypocalcemia - serum calcium-6.8 mg/dl, hence the child was evaluated further- serum PTH was 561 pg/mL (normal, 9-91 pg/mL), 25-hydroxyvitamin D was 54.1 ng/mL (normal, 5-60 ng/mL), 1,25 Vit D-6.28 pg/mL (normal, 19.9-79.3pg/mL), TSH-2.69 μUI/mL (normal, 0.35-8. 00 μUI/mL), FT4 was 1.2 ug/dL (normal, 0.9-1.8 ug/dL). Physical examination was unremarkable, and there were no stigmata of AHO, rachitic rosary, or congenital malformations. EEG was normal and CT brain did not show any intraventricular haemorrhage or basal ganglia calcification. Consistent with hypocalcaemia, hyperphosphatemia, high serum PTH levels, and lack of stigmata of AHO, we considered PHP type Ib. Her parents refused further examinations, so PTH infusion and molecular analysis of the GNAS gene could not be performed. The child was discharged in good clinical condition on calcitriol 0.25 ug/day and calcium (elemental calcium 625 mg/day) supplementation. He had no further seizures and normal serum electrolyte levels till 9 months of age. European Pseudohypoparathyroidism Network (EuroPHP Network) has recently proposed a new classification system to cover all disorders of the PTH pathway. Inactivating PTH/PTH-related protein signaling disorder (iPPSD) is the new name proposed for these disorders. iPPSDs can be further divided into subtypes: iPPSD1 to iPPSD6. A minimum of one major criterion is mandatory for the clinical diagnosis of iPPSD. Applying iPPSD criteria to this case, one can observe that they all had persistent hypocalcemia and PTH resistance but no other major or minor criteria. Nevertheless, we speculate whether neonatal transient pseudohypoparathyroidism (ntPHP) could be included among iPPSDs, specifically in the group of unknown molecular defects. Conclusion To the best of our knowledge, this is the second report in which the new classification of iPPSD has been applied and the child has been diagnosed a case of ntPHP. Presentation: No date and time listed