A genealogical study of essential hypertension with and without obesity in French Canadians.
OBJECTIVE
To investigate genetic homogeneity in a set of hypertensive families and in subsets chosen for high and low prevalence of obesity; and to compare fasting insulin and lipids, ion transport, and water homeostasis in the obese and lean families.


METHODS
The study was carried out in a relative population isolate of the Saguenay/Lac St. Jean region in Canada. Genetic homogeneity was evaluated with the mean coeffigcients of kinship (phi) and inbreeding (F) computed with ascending genealogies. Serum insulin and lipids were measured after overnight fasting. Total body water was estimated with bioelectrical impedance. Sodium-lithium countertransport and sodium-potassium co-transport were determined in freshly isolated erythrocytes.


RESULTS
F and phi were increased in hypertensive families compared with families selected at random. F and phi were further increased within the subsets of obese and lean families. In addition, fasting insulin, total body water, sodium-lithium countertransport, and sodium-potassium co-transport were higher in the obese than in the lean families. The two subsets of families did not differ by fasting lipids.


CONCLUSIONS
In the Saguenay/Lac St. Jean population, the degree of genetic homogeneity was increased in families selected for hypertension, and it was further increased in subsets of hypertensive families with high and low prevalence of obesity. This suggests that hypertension in lean and obese individuals may represent, at least in part, separate genetic entities. Some of the extra genes shared in common within the subsets may contribute to their differences in body weight, insulin sensitivity, ion transport, and water homeostasis.
Pausova
Zdenka
Z
University of Montreal Health Centre, Canada. zdenka.pausova@umontreal.ca
Jomphe
Michele
M
Houde
Louis
L
Vezina
Helene
H
Orlov
Sergei N
SN
Gossard
Francis
F
Gaudet
Daniel
D
Tremblay
Johanne
J
Kotchen
Theodore A
TA
Cowley
Allen W
AW
Bouchard
Gerard
G
Hamet
Pavel
P
D017920:Antiporters / Q000097:blood; D001692:Biological Transport; D001834:Body Water; D003241:Consanguinity; D017097:Electric Impedance; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000453:epidemiology / Q000235:genetics*; D007328:Insulin / Q000097:blood; D008055:Lipids / Q000097:blood; D008094:Lithium / Q000097:blood; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000453:epidemiology / Q000235:genetics*; D011188:Potassium / Q000097:blood; D011792:Quebec / Q000453:epidemiology; D012307:Risk Factors; D012964:Sodium / Q000097:blood
D017920:Antiporters; D007328:Insulin; D008055:Lipids; C045885:sodium-lithium countertransporter; D008094:Lithium; D012964:Sodium; D011188:Potassium