Genetic counselling

Pinki Sah
Nursing Lecturer

1. Genetic counselling Pinki Sah M.Sc. Nursing KUSMS

2. Genetics The branch of biology that deals with heredity, especially the mechanisms of hereditary transmission and the variation of inherited characteristics among similar or related organisms

3. Genetic counselling

4. Introduction Genetic counselling is a service that provide information and advise about genetic condition. These are condition caused by changes known as mutation in certain genes and are usually passed down through a family. Genetic counselling is the screening procedure designed to identify the individual having a greater risk of producing an offspring with genetic abnormalities.

5. Identification of the cases at risk is done from analysis of family and reproductive history, as well as the possible effects of environment factors. Birth of the congenitally malformed baby increases the chances to 70% as compared to a normal women.

6. DEFINITIONS Genetic counselling is a communication process which deals with the human problem associated with the occurrence or the risk of occurrence of a Genetic Disorder in a family.

7. aim The aim is to allow the women and her husband make an unified decision regarding future management of pregnancy.

8. Objectives To provide information, assist in counselling and help the couple to adjust to the problem and thereby decrease the incidence of births of genetically defective babies.

9. Every women before any prenatal genetic diagnosis, should be counseled and informed about the procedures. A formal consent is to be obtained before any invasive procedure. Information should include the nature, accuracy, safety and post test recommendations.

10. Indications for prenatal genetic counselling Maternal risk factors Maternal age ≥35 years: trisomy 21, 18, 13 and 47xxx increase with age. Family history of neural tube defects. Previous baby born with neural tube defects. Previous child with chromosomal anomaly One or both parents-carriers of sex-linked or autosomal traits. one parent is known to carry a balanced translocation.

11. 7. A child is born with an unbalanced translocation. 8. History of recurrent miscarriage. Prenatal risk factors: Oligohydramnios Polyhydramnios Severe symmetrical fetal growth restriction. Abnormal ultrasound finding (structural anomalies)

12. 5. Uncontrolled diabetes mellitus in the periconceptional period. 6. Contact with infection (teratogenic) e.g. rubella, cytomegalovirus. 7. Presence of soft tissue markers of chromosomal anomaly on ultrasonography. 8. Abnormal maternal serum screening.

13. Beneficiaries of genetic counselling People who have birth defects and genetic condition. Parents who have had a child with defects/genetic condition. Parents who have a child with developmental delay, mental retardation and other problems with growth and developments. People concerned have may have inherited a tendency to develop cancer. Couples are blood relatives.

14. TYPES OF GENETIC COUNSELLING Prospective counselling Retrospective counselling

15. PROSPECTIVE GENETIC COUNSELLING This allows for the true prevention of disease. This approach requires identifying heterozygous individuals for any particular defect by screening. Explaining to them the risk of their having affected children if they marry another heterozygote for the same gene. If heterozygous marriage can be prevented or reduced, the prospects of giving birth to affected children will diminish. EX: sickle cell anemia thalassemia

16. Retrospective genetic counselling Most genetic counseling at present is retrospective, i.e., The hereditary disorder has already occurred within the family . The methods which could be suggested under retrospective genetic counseling are: Contraception Pregnancy termination Sterilization

17. Phase of counselling Assessment phase: This is primary beginning phase of counselling in which following tasks are accomplished- Initial interview with counselee and family for preparation of counselee for genetic counselling. Carry out primary assessment of counselee physical examination etc. Considering potential diagnosis based on collected information.

18. 2 . Diagnosis phases: In some cases, the goal of genetic evaluation is to make a diagnosis of particular genetic condition/ syndrome. In other cases, the diagnosis already is known, and the genetic counselor probably will confirm the established diagnosis to proceed for next phases of the counselling.

19. Confirmatory/ supplementing tests : Chromosomal analysis Biochemical tests Molecular DNA testing X-ray, biopsy

20. Immunological test Prenatal diagnosis Linkage analysis

21. 3 . Analysis phase: This phase include followings tasks. Literature search and review of information Consultation with other experts Compiling of information and determination of recurrence risk

22. 4 . Communication phase: Communication of results and risk to the counselee and to the family if appropriate. Discussion of natural history of disorders. Current treatment options and anticipatory guidance. Assess the counselee’s understanding about facts and relevant hereditary pattern, diagnostic and management options for disorder.

23. 5. Referral and support phase Refer the individual to genetic specialist. Support of decision made by counselee. Psychological support should be providing through out of process.

24. Procedures for early detection of fetal genetic, chromosomal and structural abnormalities Maternal serum alpha feto - protein (MSAFP) Fetal cell isolation from maternal blood- genetic. From isolated fetal nucleated red blood cells or trophoblast cells. Cell free fetal DNA from maternal blood. Chorion villus biopsy High resolution ultrasonography for (nuchal thickening, nasal bone)

25. Triple test (combined test): MSAFP, Unconjugated estriol (E3) and hCG . Quadruple test: (MSAFP, UE3, hCG , Inhibit-A). Integrated test: NT, PAPP-A + hCG . Cordocentesis . Fetoscopy . Peri -implantation genetic diagnosis 3D or 4D ultrasound with increased resolution.

26. Cordocentesis (percutaneous umbilical blood sampling): it is performed under local anesthesia usually from 18-20 weeks gestation. Amniocentesis: 12-14weeks. Chorionic villus sampling: Transcervical 10-12weeks, transabdominal 10weeks to term. Fetoscopy : is done at 16-20weeks.

27. Ultrasonography (non-invasive): is done at 16-22weeks. Nasal bone: done at 10-12 weeks. Magnetic resonance imaging Pre-implantation genetic diagnosis (PGD): is done by polar body biopsy, blastomere biopsy, trophectoderm biopsy. Blastomere biopsy:

28. Fetal therapy Pre- conceptional counselling is an important step in the management so that couple has got adequate information before hand. Option for the termination of pregnancy is offered if the fetus is affected with serious genetic, chromosomal or structural abnormality. This improve the perinatal mortality statistics.

29. Intrauterine fetal transfusion for fetal anemia ( alloimmune , thalassemia) is done. Fetal medical therapy is done for various conditions through maternal medication.

30. Medicines are carried transplacentally to the fetus. Maternal oral therapy with propylthiouracil for fetal hyperthyroidism, digoxin or flecainide for fetal tachyarrhymias , oral dexamethasone for congenital adrenal hyperplasia of a female fetus, have been found effective.

31. Fetal stem cell transplantation and fetal gene therapy could be used for many hematological, metabolic, immunological and inherited diseases. Intrauterine fetal surgery has been attempted in few selected cases Common fetoscopic surgery done are: laser therapy for TTTS. Cystoscopic laser for posterior urethral valves, fetal tracheal occlusion for congenital diaphragmatic hernia and release of amniotic bands.

32. Role of the genetic counselor Educate individuals, families and communities about inheritance, testing, management, prevention, resources and research in genetic counseling. Explain family history and the chance that a condition will occur or recur. Counsel an individual or family to promote informed choices and adaptation to the risk or condition.

33. Role of nurse in genetic counselling Receive the client and family and make them comfortable in assessment room for genetic counselling. Obtain prenatal, family and other health histories from individual and family. Conduct primary physical information and collect other relevant information. Provide psychological support to individual and family throughout the counselling

34. Provide information about hereditary pattern Collect other information form individual and family e.g. any prior test report and documents others. Encourage the individual and other family members to ask questions as much as they can understand about all aspects of disorders.

35. Establish a plan of care with the family and coordination care with the family and other healthcare professionals. Maintain privacy and confidentiality of all the information. Provide referral guidance Follow up.

36. References Https://www.Webmd.Com/a-to-z-guides/what-is-genetic-counseling#2 http:// wi.mit.edu/files/wi/cfile/programs/teacher/presentations/tsipis_0607.pdf https:// www.slideshare.net/FIROZQURESHI/genetic-counseling-64020245