Non Directiveness in Genetic Counseling

Counseling is the process of presenting facts in a non biased manner. The various options should be presented and the decision should be left to the couple. Generally, it is unwise to be drawn into expressing counsellors opinion, although it is reasonable to suggest that consideration should be given to the consequence of each course of action and decision should be taken after proper thinking and not in haste. Understanding parents expectations from counseling, their eduational, social and religious background helps greatly in making counseling successful. In addition to the perceived risk of recurrence, the various factors like desire to have children, severity and burden of the disease, personal experience with the disease, availability of prenatal diagnosis may affect the reproductive decisionafter genetic counselling(7). It is essential that genetic counseling is noncoercive and nonjudgemental. The couple's decision (even if it is different from the consellor's views) should be respected and the couple be supported to carry out their decision. 

Psychological Aspects of Genetic

Counseling

The psychological needs and issues associated with genetic counseling process are many and complicated. The four phases of coping process are initial shock and denial, anger and/or guilt, anxiety and depression. The counsellor has to be aware of the natural course of events and plan his approach accordingly for successful genetic counseling. Overt and occult queries and misconceptions regarding the cause and blame should be addressed to minimize the tensions in the family members. Written summary of test reports and counseling is important not only for records but helps the family to assimilate and remember the information rightly.

Follow up sessions may be needed to reinforce the informations (usually forgotten or wrongly remembered by the consultands), to answer new queries, to provide latest information and to provide psychological support to the family during the process of coping up, till the acceptance and adjustments take place.

Prenatal Diagnosis

Availability of prenatal diagnosis for a number of disorders have made counseling and decision making easier. The various tissues that can be collected for testing are chorionic villi (10 to 12 weeks), amniotic fluid (16 to 20 weeks), fetal blood (18 to 20 weeks) and rarely fetal skin or liver biopsy. The chromosomal analysis, biochemical tests, enzyme assays or DNA tests appropriate for the disease can be carried out on the sample.

With routine use of ultrasonographic examination in many pregnancies, a number of malformations of central nervous system, gut, kidneys, limbs and heart are detected. The chromosomal analysis of such fetuses is of great help in decision of continuation of pregnancy in surgically treatable congenital malformations like duodenal atresia and for genetic counseling in others. It is essential that such fetuses should be autopsied or at least carefully examined after termination to identify associated malformations. It is found that 51% of fetuses have additional malformations which were not detected on ultrasound and genetic counseling based on ultrasonographic diagnosis is erroneous in 30% of cases(8).

Special Points in Genetic Counseling

Precise diagnosis, latest knowledge from scientific literature and good communication are the essentials of successful genetic counseling. As the genetic counsellor dispenses words and not tablets, it is difficult to judge the outcome of genetic counseling and presently no adequate scheme to assess client's satisfaction is fully developed(9). However, assessing consultants expectations beforehand and tailoring counseling accordingly leads to client's satisfaction and decreases their levels of anxiety(10).

Some relevant points regarding counseling of common pediatric genetic problems are given below:

1. Chromosomal Disorders

The risk of recurrence for aneuploidies is usually 1% or less. Parental karyotype need not be performed if the child has regular aneuploidy but must be examined if the child has a translocation, partial duplication or deficiency. Extended family studies will be required if a parent has a balanced structural rearrangement. Counseling depends on the specific type of chromosomal abnormality detected(11).

2. Autosomal Dominant Traits

The risk to each child of an affected person is 1 in 2 or 50%. However, incomplete penetrance, variable expression and sometimes, late age of onset need to be considered before genetic counseling. Examples of autosomal dominant disease are achondroplasia and tuberous sclerosis.

3. Autosomal Recessive Traits

Only if both the parents are carriers of a mutant gene, they can have an affected child. The risk of having an affected child is 25%. All the affected persons are in one generation only. The possibility of relatives of an affected person having affected children is rare because the chance that the spouse of the relative is a carrier of the same disease gene is as much as the population frequency of the gene, i.e., very little. For some diseases it may be significant, e.g., the carrier frequency of beta-thalassemia in some ethnic groups is very high.

4. X-Linked Recessive Trait

Here only males are clinically affected and related through carrier females. The chance that the carrier female has affected son is 50% and a carrier daughter is 50%. If an affected male reproduces, then all of his daughters will be carriers, and all his sons will be normal. When pedigree informations is not sufficient to decide the carrier status of a female, biochemical tests (though not absolute) or molecular tests (if available for the disease) can be of great help. The examples of X-linked recessive diseases are Duchenne muscular dystrophy and Hemophilia A and B.

5. X-Linked Dominant Inheritance

In this type of inheritance 50% children of a carrier mother are affected. Overall, there are more affected females than affected males but the manifestations in females are milder than that in the males. The examples are hypophosphatemic rickets and incontinentia pigmentosa.

6. Mitochondrial Inheritance

Over the last decade, a wide variety of de- generative diseases have been found to be associated with mutations in mitochondrial DNA. These diseases affect eyes, brain, muscles and liver predominantly. Mitochondrial mutations can either be inherited through maternal lineage (Fig. 2) or they can be acquired through the accumulation of somatic mutations in postmitotic tissues with age. The examples are Kearns Sayre syndrome: mitochondrial encephalomyopathy, lactic acidosis and stroke like episodes; and myoclonic epilepsy and ragged red fibers.

7. Congenital Malformations

Isolated congenital malformations are multifactorial. The empiric risk of recurrence is given in Table II. The risk varies according to the number of affected children, severity of the condition and sex of the person. These are simply the observed recurrence risks for different relatives of an affected individual. Before using these figures, it is essential to confirm that the malformation is isolated and not a part of a syndrome which may have a very different risk of recurrence. For example, isolated meningomyelocoele has a risk of recurrence of 5% while as a part of some autosomal recessive syndrome like Meckel Gruber or spondylocostal syndrome, the risk of recurrence is 25%. Similarly, hydrocephalus can be because of various etiolgies(12).

8. Mental Retardation

The prevalence of severe mental retardation is about 0.5% and of mild mental retardation about 2 to 2.5%. Pathologic causes of severe mental retardation are more common

than those for mild mental retardation. Genetic causes are responsible for about 40% of mentally retarded patients(13). Associated malformations and/or dysmorphism indicate a chromosomal or non chromosomal syndromic etiology. In its absence, a biochemical cause like phenylketonuria or homocystinuria needs to be investigated. If associated with neurological manifestations and/or seizures the possibility of various metabolic neurodegene-rative diseases needs to be investigated in detail. Easy labels like cerebral plasy may lead to false reassurance. Neuroimaging with CT scan and MRI identifies a number of structural malformations of brain, neuronal migrational anomalies, degenerative diseases and old vascular, hypoxic and infective insults to provide an etiology in 9 to 60% of cases(14). It is mainly indicated in cases with micro or macrocephaly or in cases with associated neurological deficit.

Fragile X mental retardation is the com  monest cause of inherited mental retardation. As the phenotype is mild, clinical diagnosis is not possible especially in young children. Thus, all mentally retarded males need to be investigated for Fragile X mental retardation. If no cause is found out then the empiric risk of recurrence of mental retardation in the sibling is 5%.

9. Perinatal Death

Seven per thousand total births have multiple congenital malformations. The etiology is diverse but genetic counseling is facilitated by chromosomal analysis, autopsy, whole body radiography and clinical photography as these investigations help in arriving at a final diagnosis in about 80% of cases. As a bare minium, photographs and radiographs should be taken which may provide a definite diagnosis in many cases(15).

The etiologic diagnosis of perinatal death will help in giving appropriate risk of recur rence and provide better prenatal diagnosis during the next pregnancy.

Concluding Comments

The pediatrician is the primary physician involved in the diagnosis and management of children with genetic disorders. In addition to providing treatment, genetic counseling should become an integral part of the management of such cases. For this, it is necessary firstly, to investigate fully, even though sometimes such investigations may not make any major change in the prognosis or treatment of the affected child. However, only with a correct diagnosis can appropriate genetic counseling be given.

Secondly, even if the parents might have brought the child for his/her treatment, it is the responsibility of the pediatrician to make them aware about the risk of recurrence and need for genetic counseling and refer them preferably to a Genetic Center before planning for the next pregnancy.

References

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3. Aase JM. Diagnostic Dysmorphology. New York, Plenum Medical Book Company, 1990.

4. Buyse ML. Birth Defect Encyclopedia. Oxford, Blackwell Scientific Publication, 1990.

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13. ICMR Collaborative Study. Multicentric study on genetic causes of mental retardation in India. Indian J Med Res 1991; 94(B): 161-169.

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15. Sharma AK, Phadke SR. Agarwal SS. The clinical value of a limited fetal autopsy. Austr NZ J Obstet Gynecol 1994; 34: 1-3.