title: OCRL1 mutation in a boy with Dent disease, mild mental retardation, but without cataracts.
abstract: BACKGROUND
  Oculocerebrorenal (Lowe) syndrome is an X-linked multisystem disease characterized by renal proximal tubulopathy, mental retardation, and congenital cataracts. We present a 19-year-old boy who was found to have low molecular weight proteinuria, hypercalciuria, mild generalized hyperaminoaciduria and intermittent microscopic hematuria at the age of 3.
  
  
  METHODS
  Standard clinical and biochemical examinations and mutational analysis of the CLNC5 and OCRL1 gene were performed for the patient.
  
  
  RESULTS
  The patient fulfilled diagnostic criteria for Dent disease, but lacked mutation in CLCN5. Sequencing of candidate genes revealed a mutation in his OCRL1 gene, which encodes for enzyme PIP2 5-phosphatase. The enzyme was not detected by western blot analysis, and decreased activity of the enzyme PIP2 5-phosphatase was observed in cultured skin fibroblasts. The boy had only mild mental retardation, mildly elevated muscle enzymes, but no neurological deficit or congenital cataracts, which are typical for Lowe syndrome.
  
  
  CONCLUSIONS
  Children with Dent phenotype who lack CLCN5 mutation should be tested for OCRL1 mutation. OCRL1 mutations may present with mild clinical features and are not necessarily associated with congenital cataracts.
authors.affiliation: Medical School Skopje, University Children's Hospital, Skopje, Macedonia. v.lozanovski@yahoo.com
authors.forename: Vladimir J
authors.initials: VJ
authors.lastname: Lozanovski
authors.forename: N
authors.initials: N
authors.lastname: Ristoska-Bojkovska
authors.forename: P
authors.initials: P
authors.lastname: Korneti
authors.forename: Z
authors.initials: Z
authors.lastname: Gucev
authors.forename: V
authors.initials: V
authors.lastname: Tasic
mesh_terms: D002386:Cataract; D002675:Child, Preschool; D057973:Dent Disease / Q000150:complications / Q000235:genetics*; D006801:Humans; D008607:Intellectual Disability / Q000150:complications / Q000235:genetics*; D008297:Male; D009154:Mutation; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics*; D012720:Severity of Illness Index
chemical_list: D010744:Phosphoric Monoester Hydrolases; C075695:OCRL protein, human