PTH and myopathy: Hypophosphatemia, high levels of parathyroid hormone, and low levels of calcitriol are the mechanism of myopathy.23 Experimental studies have also shown that skeletal muscle contains vitamin D receptors that specifically bind to 1, 25(OH) D3 and modulate various transcription factors in muscle cells.24 The factors that contributed to muscle weakness in our patients were due to neurotoxic effects, which resulted from muscle cell proliferation and differentiation into mature muscle fibers as elevated parathyroid hormone levels.25