title: Tubular Dysfunction Mimicking Dent's Disease in 2 Infants Born with Extremely Low Birth Weight.
abstract: Two preterm infants, with extremely low birth weight born at gestational weeks 24 and 25, showed generalized proximal tubular dysfunction during their stay in the neonatal intensive care unit, including glucosuria, low molecular weight proteinuria, phosphaturia, uricosuria, enzymuria (elevated urine N-acetyl-β-D-glucosaminidase), panaminoaciduria, and hypercalciuria, associated with renal calcification. Renal tubular acidosis was not present in either patient. DNA mutation analysis for Dent's disease, performed in patient 1, was negative. Although both patients had rickets of prematurity, tubular dysfunction persisted after its resolution. Patient 2, who had severe chronic lung disease, also had elevated serum creatinine, proteinuria, and hypertension, suggesting glomerular damage. In patient 1, low molecular weight proteinuria, enzymuria, panaminoaciduria, hypercalciuria, and renal calcification were still present at the age of 8 years. In patient 2, tubular dysfunction resolved except for β2 microglobulinuria at the age of 5 years. While a reduced nephron number resulting in focal segmental glomerulosclerosis is well-known, generalized proximal tubular dysfunction can also occur in infants born preterm and/or with extremely low birth weight.
authors.affiliation: Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Midori
authors.initials: M
authors.lastname: Awazu
authors.affiliation: Department of Pediatrics, Tokyo Metropolitan Ohtsuka Hospital, Tokyo, Japan.
authors.forename: Mie
authors.initials: M
authors.lastname: Arai
authors.affiliation: Department of Neonatology, Tokyo Metropolitan Ohtsuka Hospital, Tokyo, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Ohashi
authors.affiliation: Department of Pediatrics, Tokyo Metropolitan Ohtsuka Hospital, Tokyo, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Department of Pediatrics, Ohashi Hospital, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Sekine
authors.affiliation: Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Kazushige
authors.initials: K
authors.lastname: Ikeda
keywords: Fanconi syndrome; Low birth weight; Preterm infants; Proximal tubule