Established standards of medical care require that providers of genetic services obtain a history that includes family and ethnic information, inquire as to possible consanguinity, advise patients of the genetic risks to them and other family members, offer genetic testing or prenatal diagnosis when indicated, and outline the various treatment or management options for reducing the risk for disease. Although genetic counseling case management must be individualized for each patient’s needs and situation, a generic approach can be summarized (Table 16-2). In general, patients are not told what decisions to make with regard to the various testing and management options but are instead provided with information and support in coming to a decision that seems most appropriate for the patients, the consultands, and their families. This approach to counseling, referred to as nondirective counseling, has its origins in the setting of prenatal counseling, where the guiding principle is respect for an individual couple’s autonomy, that is, their right to make reproductive choices free of coercion (see Chapter 19).
Managing the Risk for Recurrence in Families
Many families seek genetic counseling to ascertain the risk for heritable disease in their children and to learn what options are available to reduce the risk for recurrence of the particular genetic disorder in question. Genetic laboratory tests for carrier testing (karyotyping, biochemical analysis, or genome analysis) are frequently used to determine the actual risk to couples with a family history of a genetic disorder. Genetic counseling is recommended both before and after such testing, to assist consultands in making an informed decision to undergo testing, as well as to understand and to use the information gained through testing.
When family history or laboratory testing indicate an increased risk for a hereditary condition in a future pregnancy, prenatal diagnosis, described in Chapter 17, is one approach that can often be offered to families. Prenatal diagnosis is, however, by no means a universal solution to the risk for genetic problems in offspring. There are disorders for which prenatal diagnosis is not available and, for many parents, pregnancy termination is not an acceptable option, even if prenatal diagnosis is available. Preimplantation diagnosis by blastocyst or blastomere biopsy (see Chapter 17) avoids the problems of pregnancy termination but requires in vitro fertilization.
Other measures besides prenatal diagnosis are available for the management of recurrence and include the following:
• Genetic laboratory tests for carrier testing can sometimes reassure couples with a family history of a genetic disorder that they themselves are not at increased risk for having a child with a specific genetic disease. In other cases, such tests indicate that the couple is at increased risk. Genetic counseling is recommended both before and after such testing, to assist consultands in making an informed decision to undergo testing, as well as understanding and using the information gained through testing.
• If the parents plan to have no more children or no children at all, contraception or sterilization may be their choice, and they may need information about the possible procedures or an appropriate referral.
• Artificial insemination may be appropriate if the father has a gene for an autosomal dominant or X-linked defect or has a heritable chromosome defect, but it is obviously not indicated if it is the mother who has such a defect. Artificial insemination is also useful if both parents are carriers of an autosomal recessive disorder. In vitro fertilization with a donated egg may be appropriate if the mother has an autosomal dominant defect or carries an X-linked disease. In either case, genetic counseling and appropriate genetic tests of the sperm or egg donor should be part of the process.