G. Livshits et al., Segregation analysis reveals a major gene effect in compact and cancellousbone mineral density in 2 populations, HUMAN BIOL, 71(2), 1999, pp. 155-172
Involvement of genetic factors in determining bone mineral density (BMD) is
doubtless. However, the exact nature of the genes governing BMD variation
and sources for genetic determination of BMD of different parts of bone (co
mpact and cancellous) have not been completely studied, The results of the
complex segregation analyses performed in our previous study (Livshits et a
l. 1996) on a Turkmenian sample strongly support the hypothesis that a sing
le Mendelian locus has a large effect on BMD. The parameter estimates for b
oth types of bone tissue were so similar that we could assume a common gene
effect for BMD variation of cancellous and compact bone. The objectives of
the present study are to test again the possibility of major gene control
of BMD in a different ethnic sample of pedigrees, namely, the Chuvasha. In
addition, we report here the results of a bivariate segregation analysis of
compact and cancellous BMD performed in both the Turkmenian and the Chuvas
ha samples of pedigrees. The results of the present study closely resemble
the results obtained on the Turkmenian pedigrees. Likewise, the major findi
ng of the present study is that there is a significant major gene effect on
both compact and cancellous BMD; polygenic hypotheses were clearly rejecte
d. Moreover, the results of the bivariate segregation analysis in both the
Chuvasha and Turkmenian samples were similar. They lead to acceptance of th
e hypothesis that there is a single major locus with pleiotropy to both com
pact and cancellous bone.