Bone Abstracts

Background: Pseudohypoparathyroidism is characterized by a resistance to parathormone, with variable phenotypical and biochemical manifestations. With genetic disorder caused by heterozygous inactivating mutations in GNAS1, the gene encoding the alpha-chain of G(s), and is associated with short stature, obesity, brachydactyly, and sc ossifications. AHO patients with GNAS1 mutations on maternally inherited alleles also manifest resistance to multiple hormones (e.g. PTH, TSH, LH, and FSH).

Presenting problem: The first patient consult at 7 years old with ataxia with serious episodes of spasticity and tapeto retinal degeneration, neuropediatric evaluation shown in tets PTH of 500 pg/ml and low ionized calcium of 1.04 mmol/l and total calcium of 7.5 mg/dl without metabolic acidosis and normal lactato piruvate test and phosphate levels, for this reason the concept was made to us. Moderate deficiency of vitamin D was treated without response in low levels of calcium and whit hypocalciuric persistence. Sestamibi test was normal also renal function. Dexa Osteodensitometer shown low bone mineral density of L1–L4. Calcitriol was begun with initial phosphate of 6.8 mg/dl, PTh of 581.9 pg/ml and hypocalciuria.

Clinical management: Two months later with high calcium diet and calcium citrate 1500 mg BID, calcitriol 0.25 μg BID. PTH antibodies was negative. Baclofen pump was initiated to this patient and clinical espasticity decrease.

Discussion: We comment some points of this clinical association and our experience with this difficult case.