Genetic Counseling (DNB Solved)

1. GENETIC COUNSELING
DNB Pediatrics solved answers, Dr.Padmesh. V
*WHO definition of counseling:
‘Genetic counselling is the process through which knowledge about the genetic aspects of
illnesses is shared by trained professionals with those who are at an increased risk or either
having a heritable disorder or of passing it on to their unborn offspring.’
*Indications for Genetic Counseling: (Nelson)
1.Advanced parental age
-Maternal age ≥35 yr -Paternal age ≥50 yr
2.Previous child with or family history of
-Congenital abnormality -Dysmorphology
-Mental retardation -Isolated birth defect
-Metabolic disorder -Chromosome abnormality
-Single-gene disorder
3.Adult-onset genetic disease (presymptomatic testing)
-Cancer -Huntington disease
4.Consanguinity
5.Teratogen exposure (occupational, abuse)
6.Repeated pregnancy loss or infertility
7.Pregnancy screening abnormality
-Maternal serum α-fetoprotein
-Maternal triple screen or variant of this test
-Fetal ultrasonography -Fetal karyotype

2. 8.Heterozygote screening based on ethnic risk
-Sickle cell anemia -Thalassemias
-Tay-Sachs, Canavan, Gaucher diseases
9.Follow-up to abnormal neonatal genetic testing
*FIVE STEPS IN GENETIC COUNSELING: (IAP Textbook)
1. Reaching at a DIAGNOSIS :
2. Risk Assessment, including risk of Recurrence:
3. Communication:
4. Discussion of Options:
5. Long term contact and support:
STEP 1. Reaching at a DIAGNOSIS : Not always straight forward!
1. First step is construction of a family tree:
-Pattern of inheritance can be obtained from Pedigree analysis.
-Various pedigree symbols
2. History taking:
3. Clinical Examination:
-Complete physical examination -Anthropometric measurements
-Accurate description of facial features & other malformations
-A photographic record can be very useful
-Examination of the parents and other relatives
4. Investigations:
-Hematological, Biochemical investigations, Imaging studies

3. -Special tests like Chromosomal analysis, Enzyme assays
-DNA analysis
STEP 2. Risk Assessment, including risk of Recurrence:
a) Detection of carriers:
- ‘Carrier’ is an individual who possesses the gene determining an inherited disease in
heterozygous state & who is essentially healthy at the time of study.
-Identifying carriers plays an important role in preventing genetic diseases.
b) Estimation of mathematical risk from the data obtained from pedigree.
c) Known data about recurrence risk: (in %)
Disorder M:F Normal parents having Affected parents
2nd affected child having an affected child 2nd affected child
CDH 1:6 4 4 10
CTEV 2:1 3 3 10
Spina bifida 2:3 5 3 -
Cleft palate 2:3 2 7 15
Cleft lip
+palate 3:2 4 4 10
Asthma 1:1 10 26 -
DM 1:1 8 8 10
STEP 3. Communication:
-Counseling to be started as early as possible.
-Rapport with both parents
-Both parents must be present during counseling.

4. -Describe genetic basis of disease using simple language and visual aids.
-Parents/Relatives should be encouraged to clarify their doubts.
COUNSELING SESSIONS MUST INCLUDE INFORMATION ON: (Nelson)
1. Information about specific condition/disorder.
2. If specific diagnosis cannot be made,explain the differential diagnosis & the emperical
options.
3. Natural History of the condition.
4. Genetic aspects & recurrence risk.
5. Options about Pre-natal diagnosis & prevention.
6. Referral to genetic specialist or endocrinologist or other specialists as required.
STEP 4. Discussion of Options:
Discuss about options available,like:
- Prenatal diagnosis - Abortion
- Not having children - Adoption
Non-directiveness: The main principle of genetic counseling is NON-
DIRECTIVENESS which is the art of presenting facts WITHOUT influencing decisions.
STEP 5. Long term contact and support: Combined approach involving
-Parents -Genetic counselor -Family physician
-Social worker -Other medical specialties
-Support groups

5. (Reference: Nelson, IAP Textbook of Pediatrics, Genetics for Clinicians by Shubha Phadke,
Genetics 2009 conference proceedings. )

6. (Reference: Nelson, IAP Textbook of Pediatrics, Genetics for Clinicians by Shubha Phadke,
Genetics 2009 conference proceedings. )