title: Insulin Receptor and the Kidney: Nephrocalcinosis in Patients with Recessive INSR Mutations.
abstract: OBJECTIVE
  Donohue and Rabson-Mendenhall syndrome are rare autosomal recessive disorders caused by mutations in the insulin receptor gene, INSR. Phenotypic features include extreme insulin resistance, linear growth retardation, paucity of fat and muscle, and soft tissue overgrowth. The insulin receptor is also expressed in the kidney, where animal data suggest it plays a role in glomerular function and blood pressure (BP) regulation, yet such a role in the human kidney is untested. Patients with biallelic INSR mutations provide a rare opportunity to ascertain its role in man.
  
  
  METHODS
  Retrospective review of patients with INSR mutations. Data for BP, renal imaging, plasma creatinine and electrolyte levels, as well as urine protein, albumin and calcium excretion were sought from the treating clinicians.
  
  
  RESULTS
  From 33 patients with INSR mutations, data were available for 17 patients. Plasma creatinine was low (mean ± SD: 25 ± 9 μmol/l) and mean plasma electrolyte concentrations were within the normal range (n = 13). Systolic BP ranged between the 18th and 91st percentile for age, sex, height and weight (n = 9; mean ± SD: 49 ± 24). Twenty-four-hour urinary calcium data were available from 10 patients and revealed hypercalciuria in all (mean ± SD: 0.32 ± 0.17 mmol/kg/day; normal <0.1). Nephrocalcinosis was present in all patients (n = 17). Urinary albumin excretion (n = 7) ranged from 4.3-122.5 μg/min (mean ± SD: 32.4 ± 41.0 μg/min; normal <20).
  
  
  CONCLUSIONS
  INSR dysfunction is associated with hypercalciuria and nephrocalcinosis. No other consistent abnormality of renal function was noted. Normotension and stable glomerular function with only moderate proteinuria is in contrast to genetically modified mice who have elevated BP and progressive diabetic nephropathy.
authors.forename: Arabella
authors.initials: A
authors.lastname: Simpkin
authors.forename: Elaine
authors.initials: E
authors.lastname: Cochran
authors.forename: Fergus
authors.initials: F
authors.lastname: Cameron
authors.forename: Mehul
authors.initials: M
authors.lastname: Dattani
authors.forename: Martin
authors.initials: M
authors.lastname: de Bock
authors.forename: David B
authors.initials: DB
authors.lastname: Dunger
authors.forename: Gun
authors.initials: G
authors.lastname: Forsander
authors.forename: Tulay
authors.initials: T
authors.lastname: Guran
authors.forename: Julie
authors.initials: J
authors.lastname: Harris
authors.forename: Iona
authors.initials: I
authors.lastname: Isaac
authors.forename: Khalid
authors.initials: K
authors.lastname: Hussain
authors.forename: Robert
authors.initials: R
authors.lastname: Kleta
authors.forename: Catherine
authors.initials: C
authors.lastname: Peters
authors.forename: Velibor
authors.initials: V
authors.lastname: Tasic
authors.forename: Rachel
authors.initials: R
authors.lastname: Williams
authors.forename: Fabian
authors.initials: F
authors.lastname: Yap Kok Peng
authors.forename: Stephan
authors.initials: S
authors.lastname: O''Rahilly
authors.forename: Philipp
authors.initials: P
authors.lastname: Gorden
authors.forename: Robert K
authors.initials: RK
authors.lastname: Semple
authors.forename: Detlef
authors.initials: D
authors.lastname: Bockenhauer
keywords: Donohue syndrome; Hypercalciuria; INSR; Insulin receptor; Leprechaunism; Nephrocalcinosis; Rabson-Mendenhall syndrome