Bone Abstracts

Background: Hypocalcaemia can be manifested by paresthesia, muscle cramps, muscle weakness, syncope, convulsions and even severe psychomotor retardation. Suchs symptoms can be initially considered as signs of epilepsy. Fahr’s disease is neurological disorder with neuropsychic changes and convulsions. Fahr’s disease is characterized by central nervous system calcifications caused by mutations in SLC20A2 gene, encoding sodium-dependent phosphate transporter 2 (PiT-2) that plays a major role in phosphate homeostasis by transporting phosphate across cell membranes. Once the calcifications are secondary to a known cause, the disease is referred to as Fahr’s syndrome.

Case Report and Clinical Management: We present a12-year old patient with partial seizures, myalgias, psychomotor retardation, and basal ganglia calcifications, initially diagnosed as having Fahr’s disease and epilepsy, where severe chronic hypocalcaemia, due to genetically confirmed pseudohypoparathyroidism type Ib (PHP Ib) was the real underlying cause. Genetic examination did not conmfirm Fahr’s disease as mutations in the SLC20A2 gene were NOT found. Mutational analysis of GNAS gene by Multiple-Ligation Probe amplification (MLPA) confirmed the diagnosis of pseudohypoparathyroidism type Ib (PHP Ib), due to methylation changes of exon I and GNAS promotor on 20q13.32. Therefore, the final diagnosis was PHP Ib with Fahr’s syndrome. Excellent clinical improvement was observed after calcium and vitamin D therapy. Currently, the boy is 16 years old, on daily calcium (1500 mg/day) and vitamin D supplementation (cholecalciferol 10 000 IU/day) and calcitriol (0.5 μg/day). His S-Ca, S-P and S-PTH are within reference ranges, he is free of convulsions, mentally fit and physically very active, without any cramps or myalgias.

Discussion and Conclusion: The serum evaluation of minerals, especially calcium and phosphate, should be performed in all patients with convulsions, cramps and psychomotor retardation. This is essential in arriving at a proper diagnosis and early initiation of appropriate treatment.

Disclosure: The authors declared no competing interests.