- Genetic Counseling.

Genetic Counseling

Definition: A process of communication and education which deals with estimating the risk of developing and/or transmitting a genetic disorder.

Goals of Genetic Counseling:

The consultand الذى يطلب الاستشارة should be provided with information and support which enables him to understand:

1.     The medical diagnosis and its consequences as: prognosis and possible treatment.

2.     Mode of inheritance of the disorder and the risk of developing or transmitting it.

3.     To make their own decisions about choices or options available for managing a particular disease and those for dealing with genetic testing and reproduction and the following risks.:

ü  Recurrence risk in future children

ü  Recurrence risk in near relatives

ü  Recurrence risk in children of unaffected brothers & sisters

A primary goal of genetic counselling is to provide information to allow for greater autonomy and choice in reproductive decisions and other areas of personal life. Avoiding additional cases of genetic disease in a family may be a consequence of genetic counselling but is not the primary aim.

Indications

1.     Maternal age > 35 years

2.     Known or suspected hereditary condition in the family

3.     Hx of child with birth defect or MR

4.     Hx of recurrent abortion

5.     Exposure to known or suspected teratogens

6.     consanguinity

Who provides counselling?

ü  In common disorder given by family doctor, physician or obstetrician

ü  Genetic counselor health care professional with master degree in human genetics & counselling.

Types:

Premarital genetic counselling Adult genetic counselling Pediatric genetic counselling

Prenatal genetic counselling Cancer genetic counselling

 

Steps in Genetic Counseling

1. listening to the questions and concerns of the patient, or family
2. Diagnosis: it is important to establish the diagnosis as clearly as possible through:

1.  Full and accurate family history and personal medical history.

2.  Full examination with referral to specialists in other fields if needed.

3.  Investigations as needed: Genetic testing, biochemical tests, X-rays, and clinical photographs.

Despite extensive investigation, including searching databases, the diagnosis may remain unknown, e.g. in children with learning disability and normal appearance or only mild and non-specific dysmorphic features.

3.     Risk Assessment

·     Calculating the recurrence risk

ü Construction of family pedigree

ü Koweledge of Medelian inheritance

ü Categorize the disease:

o   chromosomal; e.g down syndrome

o   single gene defects, using known mendelian inheritance.

o   multifactorial: using observed or empiric risk

o   environmental: no recurrence risk

·       Numerical value of a risk (quantified)

·       Nature of a risk (qualified)

·       In some cases, it may not be possible to define a precise recurrence risk and uncertainty may remain, e.g. conditions that only affect one member of a family and are known to follow autosomal dominant inheritance in some families and autosomal recessive inheritance in others (genetic heterogeneity).

4.     Discussing The Options

The consultands are provided with all information necessary to them to make their own informed decisions for management and prevention if there appears to be a risk to offspring.

·       All reproductive options should be discussed, these include:

1.  not having (any more) children

2.  reducing intended family size

3.  taking the risk and proceeding with pregnancy

4.  having antenatal diagnosis, with the selective termination of an affected fetus.

5.  For some couples, donor insemination or ovum donation may be appropriate and, for others, achieving a pregnancy through in vitro fertilization and preimplantation genetic diagnosis may be possible.

5.     Communication and Support.

ü  Counselor provides information and answer questions with truth in a manner sensitive to their ability to understand.

ü  Families often find written information helpful to refer back to, and diagrams are often used to explain patterns of inheritance. The impact of saying ‘the recurrence risk is 5% or 1 in 20’ may be different from saying ‘the chance of an unaffected child is 95% or 19 out of 20’, and so both should be presented.

ü  Psychological and emotional support.

ü  The client should be supported in the decision-making process, discussing various scenarios that could rise and to encourage them to consider their anticipated responses to the different scenarios and also the possible responses of their partner, family and others. whatever their decision they should be feel supported.  

ü  Contact with the family by telephone or nurse counselor home visits.

ü  putting parents in touch with appropriate sources of support, which provides support for families affected by rare chromosomal imbalances.

6.     Long term contact:

ü  To assess their reaction to diagnosis & recurrence risk

ü  To help them to deal with the condition effectively.

Problems in genetic counselling:

1.     Genetic hetereogenicity e.g alport syndrome

2.     Phenocopies which mimic genetic diseases e.g microcephaly which may be acquired or genetics

3.     Sporadic cases

4.     Non –paternity or questioned paternity

Counselling should be non-directive, but should also assist in the decision-making process.

Influences on decisions regarding options for genetic counselling

·       Magnitude of risk

·       Perceived severity of disorder

·       Availability of treatment

·       Person's experience of the disorder

·       Family size

·       Availability of a safe and reliable prenatal diagnostic test

·       Parental cultural, religious, or ethical values

Information from lay support groups may also be helpful.