Perspectives: screening and genetic counseling
MEN2 is a monogenic disorder and, according to its
autosomal-dominant pattern of inheritance, each affected
individual has a 50% probability of transmitting the
defective gene to progeny, independent of sex. Predictive
DNA tests are available; therefore, it is worthwhile to screen
both first- and second-grade family members. In clinically
demonstrable MTC, the specific RET mutation gives
information on the risk of developing pheochromocytoma
and HPT, the aggressiveness of MTC and clinical prognosis.
By screening family members, genetic testing allows for
early treatment and, thereby, offers the chance of prophylactic
thyroidectomy and curing the patient of MTC.
From a medical point of view, MEN2 offers a unique
model of how to use genetic information to cure a patient
with a hereditary cancer syndrome. From the point of view
of the patient, there is a loss of privacy and autonomy and a
feeling of stigmatization and discrimination. There appears
to be a threshold for patients to inform their relatives about
this hereditary disease. The confidentiality of genetic testing
must be absolute, with no exception; therefore, the duty to
inform relatives who may be at risk depends on the moral
obligation of the patient. However, many guidelines do
allow for the disclosure of results to at-risk individuals
without the patient’s consent when the information that will
be disclosed will prevent serious harm (4). Our social
attitude to rare hereditary diseases has to be reconsidered.
We need precise laws to prevent discrimination concerning
full insurance coverage and employment. Patient interest
groups may be able to providing information, support
during times of emotional distress and stand up for
common political and social aspects.
Early identification of patients with hereditary MTC using
DNA screening changes the presentation from a clinical
tumor (index case) to a preclinical disease (screening case),
resulting in a high cure rate of the affected patients by using
presymptomatic treatments, improved life expectancy and
quality of life.
AUTHOR CONTRIBUTIONS
Raue F outlined the paper, wrote all of the sections except the genotypephenotype
section, prepared the tables and figures, and checked the final
version. Frank-Raue K wrote the genotype-phenotype section, updated the
references and read the proof of the manuscript.