Defective proximal tubular function in a patient with I-cell disease.
A girl with a proven diagnosis of I-cell disease is presented. Proximal tubular dysfunction was characterized by increased excretion of low molecular proteins, aminoaciduria, hyperphosphaturia, and high/slightly increased urinary calcium. The concentration of 1,25-dihydroxycalciferol in serum was increased. Rickets were present on X-rays. As the proximal tubular dysfunction resembles the dysfunction in Dent disease, one can speculate about a common pathogenesis. Impairment of acidification in lysosomes due to loss of function of the chloride-5 channel impairs intralysosomal protease activity in Dent disease, while in I-cell disease the intralysomal protease activity is lacking.
Bocca
G
G
Department of Pediatric Nephrology, University Medical Center St. Radboud, Nijmegen, The Netherlands.
Monnens
L A H
LA
D002117:Calcitriol / Q000097:blood; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000150:complications / Q000503:physiopathology*; D007687:Kidney Tubules, Proximal / Q000503:physiopathology*; D009081:Mucolipidoses / Q000209:etiology / Q000503:physiopathology*; D012279:Rickets / Q000209:etiology / Q000503:physiopathology
D002117:Calcitriol