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Overview :
The International Myotonic Dystrophy Consortium developed
guidelines for genetic testing of individuals with or possibly with myotonic
dystrophy. These are based on a number of principles applicable to other genetic
disorders.
|
Situation |
Indication for
Testing |
Nonindication
for Testing |
|
confirmatory testing in a symptomatic patient |
(1) To confirm the diagnosis in a patient with typical
symptoms. (2) As part of the diagnostic workup of a symptomatic person in
whom the diagnosis is uncertain. |
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asymptomatic patient |
(1) To help identify which parent of an affected person
has the gene mutation in order to aid in family counseling. (2) To modify
the a priori risk of inheriting the allele. |
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minor (child or adolescent under the legal age) |
(1) Symptomatic minor, for confirmation of
diagnosis.
(2) If a compelling reason is present. |
Asymptomatic without compelling reason. |
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prenatal testing of fetal cells |
Need to assess fetal risk when a parent is or may be
affected (see below). |
Parents will have the child regardless of the
results. |
Prenatal testing of fetal cells:
(1) If one
of the parents is symptomatic and has been diagnosed with muscular
dystrophy.
(2) If one
parent is asymptomatic but has a significant risk of having the condition (based
on family studies), then the implicated parent is tested first. If the parent is
positive for the condition, then prenatal testing is performed.
Key aspects in testing:
(1) Genetic
counseling by a qualified counselor should be available to all persons having
the testing and other family members.
(2) The
person tested must be able to fully understand the risks and benefits of
testing.
(3) If
uncertainty exists in the inheritance or other features of the disease, the
health care professionals should not try to make predictions for age of onset or
severity of the disease.
(4)
Confidentiality to ensure that the persons are not subject to
discrimination.
(5)
Property rights of the DNA sample belong to the individual to whom the sample
was obtained.
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