<prompt> Causes of Hypocalcemia in a child are-DiGeorge syndromeHypoparathyroidismMagnesium deficiencyAll of above  <response>: Causes of hypocalcemia HypoparathyroidismDiGeorge syndromePTH receptor defect pseudohypoparathyroidismMagnesium deficiencyExogenous organic phosphate excessVit D difecideciency 