Recent evidence supports a genetic component contributing at least in part to this racial disparity and influencing the disease progression [4].
While there is evidence of the involvement of environmental risk factors, epidemiological twin and adoption studies also support a genetic component in the etiology of the disease [8], [9], [10] in which multiple interacting risk loci play a role [11].
Supporting a genetic component in SLE, genome-wide linkage scans have identified several loci showing significant linkage to the disease, some of which have been confirmed in independent studies (reviewed in [5] [10]).
Data from twin, family and segregation studies strongly support a genetic component.
Two sources of evidence support a genetic component, ie, transgenerational research and epidemiologic studies in twins.
The familial clustering of GCA supports a genetic component, and there is a strong association with HLA-DRB1*04 in many different populations [ 4].
Much evidence supports a genetic component of the insulin resistance (25) (36a,86a,88a), which is aggravated by environmental factors including weight gain, physical inactivity, and aging.
Emerging evidence supports a genetic component for DR, but specific genes associated with the disease have not been clearly identified despite large studies (Liew et al., 2006; Abhary et al., 2009; Sobrin et al., 2011).
All these data are congruent with those previously reported [9] and could be related to an interindividual variability in the pharmacology of verapamil supported by a genetic component [7].
The familial correlation and commingling analyses demonstrated that more than one component is needed to explain the distributions, with support for a genetic component.
