Genetics of hypertension in pregnancy: possible single gene control of pre-eclampsia and eclampsia in the descendants of eclamptic women.

Our report concerns the incidences of pre-eclampsia and eclampsia in 147 sisters, 248 daughters, 74 granddaughters, and 131 daughters-in-law of women who have had eclampsia. The disorder is highly heritable. We have analysed the data in two ways, firstly, as a single gene condition and, secondly, as a multifactorial condition. The observed incidences fit closely with the single gene model with frequency of the putative gene being 0.25. When Falconer's method of estimating heritabilities of discrete characters is used, estimates of 120% (sisters), 88% (daughters), and 105% (granddaughters)--none significantly different from 100%-are obtained. Insofar as possible, our definition of pre-eclampsia corresponds with EPH in the descriptive classification of the Organisation Gestosis and to 'severe pre-eclampsia' in Nelson's classification. The women were delivered in many different hospitals, however, and many records fail to provide all of the essential information.