Comprehensive Genetics and Nursing Study Guide

Gene

A segment of DNA that codes for a specific protein.

Genome

The entire genetic material of an individual.

Chromosome

A structure containing DNA; humans typically have 46 chromosomes arranged in 23 pairs.

Allele

Different forms of a single gene.

Genotype

The complete genetic constitution of an organism.

Phenotype

The physical appearance or observable traits resulting from genetic and environmental influences.

Mutation

A permanent change in the DNA sequence.

Carrier

A person who possesses one recessive allele for a trait but does not exhibit symptoms.

Penetrance

The likelihood that a gene will be expressed.

Expressivity

The degree to which a trait is expressed in an individual.

Autosomes

The 22 pairs of numbered chromosomes.

Sex Chromosomes

The 23rd pair of chromosomes (XX for female, XY for male).

Autosomal Dominant Disorders

Disorders that appear in every generation, affecting one parent (e.g., Huntington Disease, Marfan Syndrome).

Autosomal Recessive Disorders

Disorders that often skip generations and require two copies of a gene to express (e.g., Cystic Fibrosis, Sickle Cell Disease).

X-Linked Recessive Inheritance

Affects mostly males; carriers are typical females; no father-to-son transmission.

Down Syndrome

Caused by an extra copy of chromosome 21, characterized by various physical traits and comorbidities.

Turner Syndrome

A condition in females where one X chromosome is missing or altered.

Klinefelter Syndrome

Affects males; characterized by an extra X chromosome.

Genetic Testing

Includes types like diagnostic, carrier screening, prenatal testing, and newborn screening.

Pharmacogenomics

The study of how genetic differences affect drug metabolism and response.

Epigenetics

Changes in gene expression without altering the DNA sequence.

Multifactorial Genetic Disorders

Disorders caused by a combination of multiple genes and environmental factors.

Pedigree

A diagram representing familial relationships and inheritance patterns.

Informed Consent

Patients must understand the risks and benefits of genetic testing.

GINA

Genetic Information Nondiscrimination Act, protects against health insurance and employment discrimination.

Huntington Disease

An autosomal dominant disorder characterized by progressive neurodegeneration, leading to movement disorders and cognitive decline.

Marfan Syndrome

An autosomal dominant disorder affecting connective tissue, leading to features such as tall stature, long limbs, and cardiovascular issues.

Cystic Fibrosis

An autosomal recessive disorder that causes severe damage to the lungs and digestive system due to thick, sticky mucus production.

Sickle Cell Disease

An autosomal recessive disorder characterized by the production of abnormal hemoglobin, leading to distorted red blood cells and various health complications.

Autosomal Dominant Inheritance

A type of inheritance where a single copy of a dominant allele is sufficient to express the trait, with a 50% chance of inheritance if one parent is heterozygous (Aa) and the other is unaffected (aa).

two parents that are carriers for dominant have 75% of inheriting and 25% of not inheriting the trait across their offspring.

Autosomal Recessive Inheritance

A type of inheritance where two copies of a recessive allele are needed to express the trait, with probabilities of 25% affected (aa), 50% carriers (Aa), and 25% unaffected (AA) in offspring when both parents are carriers (Aa).

Dominant Allele

A type of allele that only requires one copy to manifest its effect in the phenotype.

Recessive Allele

A type of allele that requires two copies to manifest its effect in the phenotype.

Characteristic of Autosomal Dominant Disorders

Usually affects one parent, appears in every generation, and affects males and females equally.

Characteristic of Autosomal Recessive Disorders

Both parents are typically asymptomatic carriers, and the trait may skip generations.