Genetics Quiz Overview

NUR C202: Care of Mother and Child at Risk or with Problems (Acute and Chronic)

Course offered by Gina M. Dumawal RN, MAN at José Rizal University
Course taught by JoAnne Silbert-Flagg and Adelle Pillitteri

Genetics and Genetic Counseling

Genetics is the study of genes, heredity, and variations in living organisms.
Gregor Mendel is considered the "father of Genetics".
William Bateson coined the term "Genetics".
The human body contains 100 trillion cells, each with a nucleus containing 46 chromosomes in 23 pairs.
Chromosomes are tightly coiled strands of DNA.
Genes are segments of DNA that contain instructions for making proteins.
Inheritance patterns, such as recessive and dominant Mendelian inheritance, and chromosomal aberrations contribute to physical and cognitive disorders.
Assessing families' adjustments for inheriting genetic disorders and formulating nursing diagnoses are crucial tasks.
Planning nursing care for potential alterations in genetic health, such as amniocentesis, is essential.
Counseling families with genetic disorders and evaluating care effectiveness are important components of nursing practice.
Integrating knowledge of genetics with nursing processes is pivotal.

Introduction to Genetics

The human body contains 100 trillion cells (except red blood cells).
A nucleus exists in each human cell.
Each nucleus contains 46 chromosomes (arranged in 23 pairs).
Each chromosome in a given pair comes from each of the parents.
Tightly coiled strands of DNA are found within the chromosomes.
Genes are segments of DNA that provide instructions leading to the creation of proteins.

Introduction to Genetics

Genome: The complete set of genetic material in an organism (50,000-100,000).
A normal genome is abbreviated as 46XX (female) or 46XY (male). Chromosomal aberrations are included following the sex chromosome pattern, such as 47XX21 or 47XY21 (Down Syndrome).
Phenotype: The outward physical appearance of an individual.
Genotype: An individual's actual gene composition.
Homozygous: Having two identical genes for a specific trait.
Heterozygous: Having two different genes for a specific trait.

Introduction to Genetics

Karyotype: A schematic arrangement of chromosomes within a cell, demonstrating their number and morphology.
Hereditary traits are derived from parents.
Familial traits are transmitted through generations.
Congenital traits are present at birth (though not always genetically determined).

Introduction to Genetics

In humans, each cell has 46 chromosomes (22 pairs of autosomes and 1 pair of sex chromosomes).
Spermatozoa and ova contain only 23 chromosomes.
A like chromosome to a chromosome in the sperm cell will exist in the ovum.
For each trait, two similar genes, or alleles, are present for every trait on autosomes.

Role of Nurses in Genetics

Nurses encounter individuals and families affected by genetic diseases.
Nurses are vital links between patients and healthcare services.
Nurses require foundational knowledge of genetics.

Genetic Counseling and Interviewing

Nurses conduct interviews with patients or individuals suspected of having genetic disorders.
Detailed clinical histories and family histories (three generations) are taken.
Patients or individuals with genetic conditions are referred to the appropriate medical professionals.

Planning, Screening or Gene Based Testing Programs

Health education regarding genetics and genetic testing is provided.
Pedigree charts are drawn and interpreted.
Genetic risk assessment is performed, especially in conjunction with genetic testing options.

Monitoring

Follows up on positive newborn screening tests.
Monitors individuals with genetic disorders.
Works with families experiencing stress due to genetic disorders.

Care

Develops individualized care plans and services for affected patients.
Participates in public education about genetics.
Preserves the privacy and confidentiality of patients' genetic information.

Educational Role

Educates on the influence of genetics and environmental factors on health and disease.
Identifies Mendelian patterns of inheritance (family trees) within families.
Addresses the impact of genetic conditions on families, including social, emotional, physical, and economic implications.
Discusses the potential for guilt and depression surrounding genetic conditions in families.

Impact of Genetic Conditions on Families

Genetic conditions can lead to stress and shock within families.
Nurses provide counselling and reduce families' fears.
Nursing support includes post-test advice and consent for genetic testing.
Nurses educate and counsel families regarding genetic conditions within families.

Mechanism of Inheritance

Mode of inheritance describes how genetic traits or disorders are transferred from one generation to the next.

Classification of Genetic Disorders

Classifies genetic disorders based on single gene/monogenic, chromosomal (numerical & structural), and complex/multifactorial categories.

Single Gene or Monogenic Disorders

Genetic disorders result from mutations in a single gene.
Mendelian inheritance is used to describe this type of inheritance.
Defective genes can be located on autosomes or sex chromosomes.

Autosomal Dominant Inheritance

One mutated gene on an autosome is enough to cause effects.
Expressed in heterozygotes.
Both sexes are equally affected.
Affected individuals usually have an affected parent.
No affected person can have unaffected offspring.
50% chance of offspring inheriting the disorder.
Risks vary based on whether one or both parents exhibit the condition.

Autosomal Recessive Inheritance

Two mutated genes on an autosome are needed to cause effects.
Expressed only in homozygotes.
Affected individuals may have parents who do not exhibit the condition (carriers).
25% chance of offspring inheriting the disorder.
50% chance the offspring are carriers of the disorder.
25% chance of unaffected offspring.

X-Linked Inheritance

Genes on the X chromosome are involved.
Males typically exhibit greater effects because they have only one X chromosome.
Females are often carriers, but expression varies depending on whether the condition is dominant or recessive.
Males affected by X-linked conditions usually have unaffected maternal relatives.
Males with mutations on the X chromosome are more likely to be affected.

X-Linked Recessive Traits

Mutant gene is found on the X chromosome.
Males show more frequent effects due to having only one X chromosome.
Fathers cannot pass X-linked recessive traits to their sons.
Affected men typically have unaffected maternal relatives.
In X-linked recessive inheritance, females tend to be carriers, while males are affected more often.
When males are affected and females are normal, all sons are normal, and all daughters are carriers.

Genetic Inheritance of a Disease

Multifactorial conditions depend on multiple gene combinations and environmental factors.
No strong patterns in family history are evident.
There can be sex predilections.

Risk Factors for Genetic Disorders

Family history is a risk factor.
Prior children with genetic disorders.
Parental chromosomal abnormalities.
Advanced parental age (35 for women, 40 for men).
Previous miscarriages or stillbirths.
Prenatal exposure to chemicals or drugs.

Types of Disorders that can be Seen During Pregnancy

Single gene disorders: Caused by a change in one gene, for example cystic fibrosis, sickle cell anemia, and hemophilia.
Chromosomal abnormalities: Caused by missing, extra, or rearranged pieces of chromosomes, such as Down syndrome (Extra chromosome 21).
Multifactorial conditions: Result from a combination of genetic and environmental factors, such as cleft lip/palate, and spina bifida.

Teratogenic Disorders

Occur when the baby is exposed to substances during pregnancy that may cause abnormalities (teratogens).
First trimester is crucial pregnancy development.
Teratogens include alcohol, drugs, lead, and radiation.

Testing for Genetic Disorders

Screening tests assess the risk of a genetic disorder.
Diagnostic tests detect the presence of a specific genetic disorder.
Screening and diagnostic options are readily available to pregnant women.
Methods include a saliva sample, ultrasounds and blood tests.

Additional Advanced Diagnostic Tests

Fetal blood sampling, or Percutaneous umbilical blood sampling (PUBS), assesses for genetic disorders, used when other tests aren't viable.
Prenatal chromosome analysis (Karyotype) checks for changes in chromosomes.
Prenatal chromosomal microarray analysis (CMA) detects structural abnormalities in chromosomes.
Whole exome sequencing (WES) analyzes almost all a baby's genes.

Genetic Counseling

Genetic counselors assist pregnant or prospective parents in understanding their risks of genetic disorders.
Counselor support includes evaluating personal risk, reviewing testing options, coordinating testing process, emotional support, and decision-making.
Provides support to both parents and families when facing genetic conditions.

Treatment for Fetal Genetic Disorders

Treatment varies based on the specific disorder and the individual pregnancy.
May include specialist care from a maternal medicine physician.
Treatment plans are personalized and based on preferences.
Treatment options range from during pregnancy medical intervention to immediate post-natal surgery.
Multidisciplinary care teams are involved.
Support services are provided to families.