title: Heritability of renal function in hypertensive families of African descent in the Seychelles (Indian Ocean).
abstract: BACKGROUND
  We estimated the heritability of three measures of glomerular filtration rate (GFR) in hypertensive families of African descent in the Seychelles (Indian Ocean).
  
  
  METHODS
  Families with at least two hypertensive siblings and an average of two normotensive siblings were identified through a national hypertension register. Using the ASSOC program in SAGE (Statistical Analysis in Genetic Epidemiology), the age- and gender-adjusted narrow sense heritability of GFR was estimated by maximum likelihood assuming multivariate normality after power transformation. ASSOC can calculate the additive polygenic component of the variance of a trait from pedigree data in the presence of other familial correlations. The effects of body mass index (BMI), blood pressure, natriuresis, along with sodium to potassium ratio in urine and diabetes, were also tested as covariates.
  
  
  RESULTS
  Inulin clearance, 24-hour creatinine clearance, and GFR based on the Cockcroft-Gault formula were available for 348 persons from 66 pedigrees. The age- and gender-adjusted correlations (+/- SE) were 0.51 (+/- 0.04) between inulin clearance and creatinine clearance, 0.53 (+/- 0.04) between inulin clearance and Cockcroft-Gault formula and 0.66 (+/- 0.03) between creatinine clearance and Cockcroft-Gault formula. The age- and gender-adjusted heritabilities (+/- SE) of GFR were 0.41 (+/- 0.10) for inulin clearance, 0.52 (+/- 0.13) for creatinine clearance, and 0.82 (+/- 0.09) for Cockcroft-Gault formula. Adjustment for BMI slightly lowered the correlations and heritabilities for all measurements whereas adjustment for blood pressure had virtually no effect.
  
  
  CONCLUSIONS
  The significant heritability estimates of GFR in our sample of families of African descent confirm the familial aggregation of this trait and justify further analyses aimed at discovering genetic determinants of GFR.
authors.affiliation: Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, Ohio, USA.
authors.forename: Murielle
authors.initials: M
authors.lastname: Bochud
authors.forename: Robert C
authors.initials: RC
authors.lastname: Elston
authors.forename: Marc
authors.initials: M
authors.lastname: Maillard
authors.forename: Pascal
authors.initials: P
authors.lastname: Bovet
authors.forename: Laurent
authors.initials: L
authors.lastname: Schild
authors.forename: Conrad
authors.initials: C
authors.lastname: Shamlaye
authors.forename: Michel
authors.initials: M
authors.lastname: Burnier
mesh_terms: D000349:Africa / Q000208:ethnology; D003404:Creatinine / Q000378:metabolism; D005260:Female; D005919:Glomerular Filtration Rate / Q000235:genetics; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000235:genetics* / Q000503:physiopathology*; D007444:Inulin; D007668:Kidney / Q000503:physiopathology*; D007676:Kidney Failure, Chronic / Q000209:etiology; D008297:Male; D008875:Middle Aged; D012042:Registries; D012307:Risk Factors; D012750:Seychelles; D035781:Siblings
chemical_list: D007444:Inulin; D003404:Creatinine