BIOLOGY Volume 3 - A Guide to General Biology - 2004

25. APPLIED GENETICS

25.7. Human Genetics

25.7.10. Genetic Counselling

The purpose of genetic counselling is to provide clients with comprehensive information regarding the likelihood of inherited disorders and their potential consequences. Referrals for genetic counselling may come from general practitioners, medical specialists, or social workers. Counselling is typically conducted in clinical settings, with specially trained physicians or pediatricians acting as counsellors. They must have a thorough understanding of medical genetics and possess strong interpersonal and communication skills. A counsellor has no right to impose their personal viewpoint on patients. Instead, individuals should be helped to make their own informed decisions based on the provided information and an empathetic Structure/133.html">Discussion of the issue.

Some of the key issues relevant to counselling are outlined below.

Diagnosis OF THE CONDITION. The primary objective is to establish an accurate diagnosis, which involves physical examination and laboratory testing. For instance, a 20-year-old female presenting with primary Amenorrhea and underdeveloped breasts may have Turner syndrome, a hormone deficiency, or simply delayed Puberty. Chromosomal analysis can help determine whether these Clinical Features are associated with Turner syndrome.

FAMILY HISTORY. The counsellor is responsible for determining whether There is a history of Genetic Disorders in previous generations and, if so, how affected individuals are related to the client. This is usually accomplished by constructing a pedigree.

RISK CALCULATION. Genetic counselling frequently requires calculating the probability of having an affected child. This is particularly important when there is a prior history of genetic disorders within the family. For example, if both parents are carriers of a recessive Gene, they can be informed that there is a one-in-four chance that their child will be affected. It is crucial for parents to understand that this probability applies independently to each Pregnancy. In one case, after advising a couple who already had an affected child, a physician stated the risk using these exact terms; however, the parents misinterpreted the explanation. They assumed that because they already had one affected child, their next three children would certainly be healthy. When another affected child was subsequently born, they filed a lawsuit against the counsellor. Counsellors must also be equipped to explain more complex situations, such as X-linked conditions (e.g., hemophilia) or polygenic disorders (e.g., Spina bifida, cleft lip, and Clubfoot). In such cases, calculating risk is considerably more difficult, and counsellors must rely on statistical data. For instance, cleft lip and palate occur with a frequency of 1 in 1,000 births in the general population, yet they are 40 times more common among the siblings of affected children. Older women often wish to know the likelihood of having a child with Down syndrome, especially if they have previously given birth to such a child.

EXPLANATION OF CAUSE. The counsellor must clearly explain the underlying cause and nature of any given condition. For instance, all the distressing symptoms of Sickle-Cell Anemia stem from the abnormal shape of THE RED Blood Cells (sickle-shaped instead of round); this leads to anemia and the occlusion of small Blood Vessels, which in turn triggers a cascade of other health complications.

QUALITY OF LIFE. It is essential to address issues related to the quality and expected life expectancy of an affected child. Discussions should cover Treatment options, the availability of support groups and financial assistance, as well as the psychological burdens placed on the family when an affected child requires intensive time and costly care.

REPRODUCTIVE OPTIONS. If a couple concludes that the risk is unacceptable to them, various alternatives can be offered, including Contraception, sterilization, adoption, or Artificial Insemination using donor sperm—all of which prevent the transmission of the father's genes. If the genetic issue originates with the female partner, In vitro Fertilization (IVF) using a donor egg may be appropriate. Prenatal diagnostic Procedures, such as amniocentesis and chorionic villus sampling, must also be discussed. Furthermore, the reliability of any proposed testing, such as DNA analysis or ultrasound scanning, needs to be clearly explained. In the near future, Gene Therapy is expected to become a viable option (Section 25.7.11).

GENETIC SCREENING. Part of the counsellor's role is to discuss the results of genetic screening with individuals who have undergone testing. Section 25.7.9 outlined three categories of screening: prenatal diagnosis, carrier testing, and predictive diagnosis. The Importance of this discussion increases significantly when screening yields a positive or adverse result. Individuals experiencing emotional Shock often struggle to make decisions with long-term consequences, making the support of a counsellor indispensable in such situations. As the number of available genetic tests continues to grow, The Role of the counsellor will become increasingly vital.

RESPONSIBILITY. When the transmission of a disorder is attributable to one partner (as in the case of dominant genes or X-linked conditions), that individual frequently experiences feelings of guilt. The counsellor must help them overcome these emotions by explaining that everyone carries various deleterious genes.