Hereditary tumor
There are cases in which a person is born with a genetic difference that predisposes
them to cancer. Such cases are called “hereditary tumor,” as the predisposition to
cancer can be passed on to the next generation. These tumors account for several
percent of all cancers. Genome analysis of cancers sometimes gives results that
are suggestive of hereditary tumors. Patients who wish to learn more about
hereditary tumors, including the risk that they or their family members may suffer
cancer in the future, are able to receive genetic counseling. Patients may also
request not to be informed in the event that a test gives a result suggesting
hereditary tumor.
Rare/Intractable disease
Under the Rare/Intractable Disease Law, there are 333 designated rare/intractable
diseases (diseases that meet the following five criteria: unknown mechanism of
pathogenesis, no established treatment, the disease is rare, long-term treatment is
necessary, and objective diagnostic criteria have been established) that are eligible
for subsidized medical care. From a genetic perspective, these diseases may be
classified into those consisting of monogenic diseases alone, those consisting of
mixed monogenic and multifactorial diseases, and those consisting of multifactorial
diseases alone. In addition, diseases that are not designated as rare/intractable
diseases and for which a disease concept has not yet been fully established are
also included in the present plan as rare/intractable diseases in the broad sense of
the term.
Monogenic disease
A hereditary disease caused by mutation of a single gene.
Multifactorial disease
A disease caused by multiple genetic factors, as well as environmental factors,
lifestyle, and aging.
Pathogenic variantsA change in the base sequence of the genome. Somatic
mutations in cancer cells that are acquired (i.e., not present at birth) are generally
referred to as pathogenic variants.
Polymorphism
An individual variation in the germline seen in the genome sequence that occurs at
a frequency of 1% or more in a population.
Variant
Various individual differences in the germline seen in the genome sequence. Those
that are related to disease are called pathogenic variants.

*This glossary was prepared by the MHLW Science Research Group for promotion
of whole genome analysis of cancer and establishment of a system for technology
assessment related to whole genome analysis of each individual patient and its
clinical application, a center for data analysis and storage, information security and
patient confidentiality, and Ethical Legal and Social Implications (ELSI) (tentative
name).

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