Amelioration of Hypophosphatemic Rickets and Osteoporosis With Pamidronate and Growth Hormone in Lowe Syndrome

The oculocerebrorenal syndrome of Lowe, an X-linked multisystem disorder, was diagnosed in a male patient who presented with typical abnormalities of the eyes, kidneys and nervous system. Besides congenital cataracts, renal tubular dysfunction and psychomotor retardation, the patient had also suffered from profound failure to thrive, growth hormone deficiency severe osteoporosis with hypophosphatemic rickets, and progressive renal dysfunction since early childhood, which were attributed to the metabolic derangements following Fanconi syndrome. Direct sequencing of the OCRL1 gene (responsible for the oculocerebrorenal syndrome of Lowe) revealed a tie novo c.2282_2283insT in exon 20, which resulted in premature termination of translation (D762X). After monthly intravenous administration of pamidronate since the age of 17.8 years, his Urine creatinine clearance and tubular resorption of phosphate increased slightly and bone mineral density was much improved (Z score increased from -7.3 to -3.3) without deterioration of renal function. Simultaneous growth hormone therapy enhanced the positive response. The beneficial osseous and renal effects of the bisphosphonate, along with growth hormone treatment in Lowe syndrome with hypophosphatemia, may be related to reduced renal calcium and phosphate excretion. [J Formos Med Assoc 2009;108(9):730-735]