HBG 27 ( Genetic ; Screening, Prenatal and Counselling)

• Genetic Testing:

  • DNA testing involves the analysis of human DNA in any of its forms or related products such as chromosomes, RNA, and proteins
  • It looks for changes in chromosomes, genes, or proteins
  • DNA can be extracted from various sources like blood, urine, saliva, body tissues, bone, and hair
  • Types of tests include Molecular Tests, Cytogenetic Tests, and Biochemical Tests
• • Reasons for genetic testing include identifying specific genes, genetic lineage, confirming or ruling out inherited genetic disorders, assessing the risk of developing or passing on a genetic disorder, and selecting effective drugs based on genetic profile
• Genetic Testing Tools:

  • DNA analysis tools include PCR, Gel electrophoresis, Sequencing, RFLP analysis, Real-time PCR, Dot blot, and Microarray
  • Chromosome Analysis tools include Conventional methods, Fluroscence In Situ Hybridization (FISH), and Comparative Genomic Hybridisation (CGH) ArrayMicroarray Realtime PCR
• Prenatal Diagnosis:

  • Prenatal diagnosis involves identifying fetal structural or functional abnormalities (birth defects)
  • Prenatal Testing is offered if the suspected condition can be diagnosed before birth
  • Prenatal Screening Test requires analyzing tissue, blood, or fluid to determine the presence or absence of a condition
  • Prenatal Diagnostic Test is possible for almost all chromosomal disorders but not all genetic ones
  • The goal is to help parents make informed decisions about the health of their unborn child
• Invasive Diagnostic Techniques:

  • Amniocentesis is performed between 15 & 18 weeks, involves removing amniotic fluid for analysis, and carries a risk of miscarriage
  • Chorionic villus sampling is done between 10 and 12 weeks, involves analyzing cells from the chorionic villi, and has a risk of miscarriage
  • Cordocentesis or PUBS is performed after 18 weeks to obtain fetal blood for rapid chromosome analysis
• Genetic Counselling:

  • Genetic counselling helps people understand and adapt to the medical, psychological, and familial implications of genetic contributions to disease
  • It involves interpreting family and medical histories, educating about inheritance, testing, management, prevention, and providing counseling for informed choices and adaptation to risks or conditions
  • The aim is to promote informed decisions and assist clients/patients & families in coping with the impacts of disorders
• Pedigree:

  • Pedigree is a graphic presentation of a family's health history and genetic relationships
  • It is used for establishing rapport, as a diagnostic tool, identifying mode of inheritance, identifying at-risk relatives, deciding on testing strategies, and distinguishing genetic from other risk factors
• Goals of Prenatal Diagnosis and Counselling:

  • Assess pregnancy and determine specific risks to the fetus
  • Evaluate prenatal diagnostic options and educate the family about diagnosis, likely outcomes, and management options
  • Discuss risks, benefits, and uncertainties, explore family concerns, provide risk assessment for other family members, and offer psychosocial support and follow-up
• Genetic Testing:

  • DNA testing involves the analysis of human DNA in any of its forms or related products such as chromosomes, RNA, and proteins
  • It looks for changes in chromosomes, genes, or proteins
  • DNA can be extracted from various sources like blood, urine, saliva, body tissues, bone, and hair
  • Types of tests include Molecular Tests, Cytogenetic Tests, and Biochemical Tests
• • Reasons for genetic testing include identifying specific genes, genetic lineage, confirming or ruling out inherited genetic disorders, assessing the risk of developing or passing on a genetic disorder, and selecting effective drugs based on genetic profile
• Genetic Testing Tools:

  • DNA analysis tools include PCR, Gel electrophoresis, Sequencing, RFLP analysis, Real-time PCR, Dot blot, and Microarray
  • Chromosome analysis tools include Conventional methods, Fluroscence In Situ Hybridization (FISH), and Comparative Genomic Hybridisation (CGH) ArrayMicroarray Realtime PCR CGH
• Prenatal Diagnosis:

  • Prenatal diagnosis involves identifying fetal structural or functional abnormalities
  • Prenatal testing is offered when a suspected condition can be diagnosed before birth
  • Prenatal screening tests aim to determine if a condition is present or absent
  • Prenatal diagnosis is possible for most chromosomal disorders but not all genetic ones
  • The goal is to help parents make informed decisions about the health of their unborn child
• Prenatal Diagnostic Techniques:

  • Non-invasive techniques include Ultrasound and Magnetic Resonance Imaging (MRI)
  • Invasive diagnostic techniques like Amniocentesis and Chorionic villus sampling are performed between 15-18 weeks of pregnancy
  • Risks of invasive techniques include miscarriage and physical discomfort
  • Chorionic villus sampling involves analyzing cells from the villi to detect genetic and biochemical makeup
• Genetic Counselling:

  • Genetic counselling helps people understand and adapt to the medical, psychological, and familial implications of genetic contributions to disease
  • It involves interpreting family and medical histories, educating about inheritance, testing, management, prevention, and providing counseling for informed choices and adaptation to risks or conditions
  • Genetic counselling aims to promote informed decisions, assist in coping with disorders, and does not aim to reduce the incidence of genetic diseases
• Pedigree:

  • Pedigree is a graphic presentation of a family's health history and genetic relationships
  • It is used for establishing rapport, diagnostic purposes, identifying mode of inheritance, at-risk relatives, testing strategies, and distinguishing genetic from other risk factors
• Goals of Prenatal Diagnosis and Counselling:

  • Assess pregnancy and determine specific risks to the fetus
  • Evaluate prenatal diagnostic options and educate the family about diagnosis, outcomes, and management options
  • Discuss risks, benefits, uncertainties, family concerns, provide risk assessment for other family members, and offer psychosocial support and follow-up