Hypertension in Only One of Identical Twins

Genetic Variance in Blood Pressure

“…Had we, in the present study, examined less than 168 pairs of MZ and DZ twins, a difference in the withinpair variance as large as we observed would not have been statistically significant. Thus, we believe the large number of twins we examined, and of course, the difference in analytic methods mentioned above, could explain the difference between our data, demonstrating a clear impression of a major genetic determination in blood pressure variation, and those reported by other investigators in previous twin studies of blood pressure and hypertension (Stocks 1930, Friedman and Kasanin 1943, Hines et al 1957, Mathers 1961, Lundman 1966, Downie et al 1969, Vander 1970).…”

“…The role of genetic factors in the genesis of essential hypertension has been under intensive investigation for several decades (Stocks 1930, Friedman and Kasanin 1943, Hines et al 1957, McKusick 1960, Mathers et al 1961, Schweitzer 1962, Harvald and Hauge 1963, Murphy 1964, Lundman 1966, Pickering 1968, Downie et al 1969. Although clinicians recognize the familial aggregation in hypertension, this observation is not sufficient evidence that hypertension is a genetically determined disease.…”

“…These are studies of records of single families, studies of family histories in large series of patients with hypertension, studies of measurements of blood pressure in relatives of patients with hypertension, and studies of blood pressure in twins. Of all these, measurements of blood pressure among twins are perhaps the most revealing (Stocks 1930, Friedman and Kasanin 1943, Hines et al 1957, Mathers, 1961, Lundman 1966, Downie et al 1969, Vander 1970. Indeed, for a variety of reasons, studies of records of single families and studies of family histories of patients with hypertension are of little value in providing evidence of heritability of hypertension (Pickering 1968).…”

Psychological and Physical Features in Hypertension

“…Robinson and Burch described cases of hypertension in which psychotherapy markedly improved symptoms and anxiety, but the individuals remained hypertensive. Friedman and Kasanin described two twins with consequent hypertension and emotional difficulties, with repressed aggressiveness; in two other sets of twins, in whom there were no such hostilities, there was no hypertension [19,[49][50].…”