Although almost every disease has a genetic
component, most diseases are not inherited
in predictable, single-gene patterns (dominant,
recessive, x-linked). That is why most
of the conditions that burden us from
a public health perspective – caries,
diabetes, heart disease – are called
"complex." Complex diseases
arise from a combination of factors, including
the interaction of multiple genes, lifestyle
choices, and environmental exposure.
Although these conditions are more frequent,
their patterns of transmission are more
elusive because the disease traits don’t
segregate
neatly from generation to generation,
as do single-gene disorders. Instead,
complex traits aggregate
or cluster within families, and it is
difficult to predict who will be affected
and how the disease will express itself.
As the following case illustrates, however,
the unique perspective of dentists and
hygienists can sometimes hold the key
to identifying families at high risk for
common, complex disorders.
