Genetics Conceptual Framework Flashcards

Vocabulary flashcards covering clinical definitions, genetic disorders, inheritance patterns, and diagnostic procedures in nursing genetics.

Genetics

The study of heredity and the variation of inherited characteristics, or the study of ways genetic disorders occur.

Genetic Counseling

A communication process providing families with necessary information to make informed decisions about their unborn child and genetic conditions.

Genetic Disorders

Also referred to as Inherited Disorders; these result from a disorder in gene or chromosome structure and can be passed from one generation to the next.

Sex Cells

Mature reproductive cells produced by meiosis, also called gametes, containing only $23$ chromosomes (haploid).

Somatic Cells

Body cells containing $46$ chromosomes (diploid) that multiply by mitosis.

Genome

The entire complement of genes carried by a cell; normal complete examples include $46XX$ (female) or $46XY$ (male).

Chromosomes

Small, rod-shaped structures in the nucleus carrying hereditary material on tightly coiled strands of DNA.

Deoxyribonucleic Acid (DNA)

A double stranded helix that serves as the blueprint of life and forms chromosomes.

Allele

Alternate forms of the same gene from a sperm and an ovum, typically consisting of two like genes for every trait.

Genotype

The actual gene composition of an individual.

Phenotype

The outward appearance or the expression of genes.

Dominant Gene

An allele that produces an effect regardless of the state of the corresponding allele, usually represented by a capital letter.

Recessive Gene

A non-dominant allele that produces an effect only when it is transmitted by both parents.

Homozygous

Having two like genes for a trait, such as $AA$ or $aa$.

Heterozygous

Having two different genes for a trait, such as $Aa$.

Carrier

A clinically normal individual who is heterozygous for an abnormal gene.

Trisomy

A chromosomal abnormality featuring three copies of a particular chromosome instead of the normal two.

Monosomy

A chromosomal abnormality characterized by the presence of only $1$ chromosome from a pair.

Mosaicism

The presence of two or more sets of cells that differ in genetic make-up but arise from a single cell.

Aneuploidy

Numerical chromosome errors, such as having $45$ or $47$ chromosomes, which often result in major developmental defects.

Gregor Mendel

The individual known as the Father of Modern Genetics.

Punnett Square

A big square divided into four little ones used to predict genetic outcomes.

Monohybrid Cross

A genetic cross that refers to the tracking of one single trait only.

Dihybrid Cross

A genetic cross involving two or more traits, such as $AaBb \times AaBb$.

Complete Dominance

A dominance relation where the dominant allele completely masks the expression of the recessive one.

Incomplete Dominance

A condition where neither allele appears to mask the other completely, resulting in a blended phenotype such as a pink flower.

Codominance

A state where both alleles are fully functional and express themselves individually in a heterozygous condition, such as in blood type $AB$.

Huntington’s Disease

A chronic, progressive autosomal dominant disorder of the nervous system characterized by involuntary choreiform movement and dementia.

Chorea

Rapid, jerky, involuntary, and purposeless movements associated with disorders like Huntington's Disease.

Fascioscapulohumeral Muscular Dystrophy

An autosomal dominant disorder characterized by muscle weakness in the face, shoulder blades, and upper arms.

Osteogenesis Imperfecta

Also referred to as brittle bone disease, it is characterized by excessive fractures and bone deformity.

Marfan Syndrome

A connective tissue disorder caused by defects in the fibrillin-1 gene, characterized by a tall and thin body structure and long limbs.

Waardenburg Syndrome

A group of genetic conditions causing hearing loss and changes in hair, skin, and eye color.

Cystic Fibrosis

The most fatal autosomal recessive disease, affecting both exocrine and endocrine glands with multi-system involvement.

Albinism

A condition characterized by the total absence of pigment melanin, resulting in light skin and increased sun sensitivity.

Tay Sach’s Disease

A disorder caused by the absence of an enzyme that breaks down gangliosides, leading to toxic build-up in the brain and loss of motor skills.

Adrenogenital Syndrome

Enlargement of the adrenal glands caused by excessive secretion of androgenic hormones, leading to masculinization or feminization.

Phenylketonuria (PKU)

An inherited disorder leading to toxic levels of phenylalanine in the blood, resulting in CNS damage and musty breath odor.

Galactosemia

A disorder affecting how the body processes galactose; milk consumption can lead to liver, kidney, and brain damage in infants.

Limb-Girdle Muscular Dystrophy

A group of diseases causing weakness and wasting in the muscles closest to the body, such as the shoulders and pelvic area.

Rh Factor Incompatibility

A condition occurring if a pregnant woman has Rh-negative blood and her baby has Rh-positive blood.

X-Linked Hypophosphatemia

An X-linked dominant disorder characterized by low levels of phosphate in the blood and bone pain.

Rett Syndrome

A neurological X-linked dominant disorder causing progressive loss of motor skills, speech, and slowed growth of the head.

Alport Syndrome

An X-linked dominant condition characterized by kidney disease, hearing loss, and eye abnormalities.

Hemophilia A & B

X-linked recessive bleeding disorders resulting from congenital deficiency of Factor VIII or Factor IX respectively.

Fragile X Syndrome

A genetic condition causing learning disabilities and cognitive impairment, characterized by an elongated face and broad forehead.

Duchenne Muscular Dystrophy

A disorder involving progressive muscle degeneration due to alterations in the protein dystrophin.

Polyploidy

A condition where a cell acquires one or more additional sets of chromosomes, resulting in multiples of the haploid number.

Down Syndrome

Also known as Trisomy $21$ ($47XX21$ or $47XY21$), characterized by Brushfield spots, a protruding tongue, and a peculiar crease on the palms.

Edwards’ Syndrome

Also known as Trisomy $18$ ($47XX18$ or $47XY18$), characterized by rocker-bottom feet and severe cognitive challenges; survival is rare beyond infancy.

Patau Syndrome

Also known as Trisomy $13$ ($47XX13$ or $47XY13$), characterized by cleft lip and palate and microcephaly.

Turner Syndrome

Also known as Gonadal Dysgenesis or $45X0$, characterized by short stature, streak ovaries, sterility, and a webbed neck.

Klinefelter Syndrome

A condition described as $47XXY$, occurring in males with an extra X chromosome, characterized by gynecomastia and infertility.

Balanced Translocations

A situation where a chromosome is misplaced or abnormally attached to another, but the total count remains $46$, resulting in normal appearance and function.

Unbalanced Translocations

A situation where meiosis results in an extra chromosome (such as number $21$) being included in a gamete, resulting in a total of $47$ chromosomes.

Inversions

A structural abnormality resulting from two breaks on a chromosome with the segment being reinserted in reverse; usually non-viable to conception.

Deletions

A structural abnormality where part of a chromosome breaks off during cell division, such as in Cri-du-chat syndrome.

Cri-du-chat Syndrome

A syndrome caused by a partial deletion on the short arm ($p$) of chromosome $5$.

Classical Karyotyping

A procedure where lymphocytes are grown to metaphase, stained, and photographed to study chromosome structure.

Chromosome Microarray Analysis (CMA)

Also known as Molecular Karyotyping, it studies individual genes and serves as a first-tier prenatal diagnosis for conditions like cystic fibrosis.

Nuchal Translucency Screening

A first-trimester sonogram that measures fluid buildup at the back of the baby's neck to identify Down syndrome or Turner syndrome.

Chorionic Villi Sampling

A highly accurate but risky exam where chorion cells are removed vaginally via catheter for DNA analysis.

Amniocentesis

The withdrawal of $20$ to $30$ $mL$ of amniotic fluid at $15th$ to $20th$ week gestation via abdominal wall guided by ultrasound.

Percutaneous Umbilical Blood Sampling (PUBS)

Also known as cordocentesis, it is the removal of blood from the fetal umbilical cord at $17$ weeks.

Fetoscopy

The insertion of a fiber optic fetoscope through a small incision in the mother's abdomen into the uterus.

Newborn Screening

A blood heel prick analysis performed $24$ to $48$ hours after birth.

Preimplantation Diagnosis

A procedure applicable only to IVF where sperm and ova are assessed before implantation.

Alpha-fetoprotein (AFP)

A marker in maternal serum screening; increased levels may indicate neural tube defects like spina bifida.

Unconjugated Estriol

A marker in maternal serum screening where certain levels suggest Down syndrome.