Disorders of the Human Body - NUR 5240

ALLELE

Any of one or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome. These variations account for the differences in inherited characteristics. Alleles can be either dominant (expressed even when paired with a different allele) or recessive (only expressed when paired with an identical allele).

TERATOGENS

Any substance, organism, or factor that can cause harm to fetal development. Teratogens can lead to birth defects or developmental disabilities. The severity and type of defect often depend on the timing and extent of exposure during pregnancy.

Examples:

  • Infections (Rubella, Syphilis, Zika virus)

  • Drugs (Alcohol, Thalidomide, Isotretinoin)

  • Certain medications (Warfarin, ACE inhibitors)

  • Chemicals (lead, mercury, PCBs)

  • Radiation: High levels of radiation exposure (X-rays, radiation therapy)

AUTOSOMES

Chromosomes that are not sex chromosomes (i.e., not X or Y chromosomes). Humans have 22 pairs of autosomes.

GENOTYPE

The genetic makeup of a person (e.g., a blue-eyed person can have a bb genotype if blue eyes are recessive). It refers to the specific set of genes or alleles an individual possesses.

KAROTYPE

The number and appearance of chromosomes in the nucleus of a eukaryotic cell. It includes the size, banding pattern, and number of chromosomes. Karyotyping is used to identify chromosomal abnormalities.

PHENOTYPE

How the gene mix is manifested in the individual; the expression or appearance (e.g., blue eyes, blond hair, height). It is the observable characteristics or traits resulting from the interaction of its genotype with the environment.

Genetic & Congenital Disorders

Broad category encompassing disorders caused by genetic mutations or present at birth. These disorders can result from a variety of genetic and environmental factors.

Autosomal Dominant

Disorder where only one copy of the abnormal gene is needed to cause the disease. If a parent has the disorder, there is a 50% chance their child will inherit it. The gene is located on one of the non-sex chromosomes.

Autosomal Recessive

Disorder where two copies of the abnormal gene are needed to cause the disease. Individuals with only one copy are carriers. There is a 25% chance that both parents who are carriers will have an affected child.

Sex Chromosomes

Disorders involving the X and Y chromosomes. These disorders can affect sexual development and various other traits.

Autosomal Dominant Disorders

A disorder where only one copy of the abnormal gene is needed to cause the disease. Parents with autosomal dominant disorder will pass along the disorder to half of their children. Examples:

  • Marfan’s Syndrome

  • Huntington’s Chorea

  • Von Recklinghausen disease

Autosomal Recessive Disorders

A disorder where two copies of the abnormal gene is needed to cause the disease Examples:

  • Cystic fibrosis

  • Tay-Sachs disease

  • Gaucher’s disease

  • Phenylketonuria (PKU)

  • Galactosemia

Sex Chromosomes Disorders

Sex chromosome are disorders that affect X and Y or sex chromosomes. Examples:

  • Klinefelter’s syndrome

  • Turner’s syndrome

Trisomy 21 (Down Syndrome)

  • Patho: Extra copy of chromosome 21

  • Signs/symptoms: Intellectual disability, flat facial features, short stature, heart defects. Other common features include a single deep crease across the palm of the hand, almond-shaped eyes, and poor muscle tone.

Cri du chat syndrome

  • Patho: Deletion on the short arm of chromosome 5

  • Signs/symptoms: High pitched cry (like a cat), intellectual disability, small head, low birth weight. Can cause feeding difficulties and respiratory issues.

Huntington’s Chorea

  • Patho: CAG repeat expansion on chromosome 4, causing brain degeneration

  • Signs/symptoms: Uncontrolled movements (chorea), mood swings memory loss, personality changes. Symptoms typically appear in mid-adulthood (30s-40s).

Marfan’s Syndrome

  • Patho: Defect in the fibrillin-1 gene affecting connective tissue

  • Signs/symptoms: Tall, long limbs, flexible joints, heart valve problems, risk of aortic rupture, visual problems, low back pain. Monitor aortic health very closely.

Von Recklinghausen’s Disease

  • Patho: Mutation in the NF1 gene affecting tumor suppressor function

  • Signs/symptoms: Cafe-au-lait spots, benign tumors on nerves (Neurofibromas), possible learning disabilities. Variable in severity and presentation.

Osteogenesis imperfecta

  • Patho: Defect in collagen type 1 synthesis

  • Signs/symptoms: Fragile bones, blue sclera, hearing loss, dental problems. Severity varies widely among individuals.

Nonne- Milroy- Meige syndrome

  • Patho: Genetic mutation causing congenital lymphedema

  • Signs/symptoms: Swelling in the legs (lymphedema), sometimes visible at birth or early childhood. Often affects both legs.

Cystic Fibrosis

  • Patho: Mutation in the CFTR gene leads to thick, sticky mucus

  • Signs/symptoms: Chronic lung infections, difficulty breathing, salty sweat, poor weight gain. Affects multiple organ systems, including the lungs, pancreas, and digestive system.

Tay-Sachs Disease

  • Patho: Deficiency of hexosaminidase A enzyme; buildup of GM2 gangliosides in the brain

  • Signs/symptoms: Progressive weakness, loss of motor skills, blindness (cherry-red spot in retina), early death in childhood. Most common in Ashkenazi Jewish population.

Gaucher’s Disease

  • Patho: Deficiency of glucocerebrosidase enzyme; lipid buildup in organs

  • Signs/symptoms: Enlarged spleen and liver, bone pain, easy bruising, fatigue. Can be treated with enzyme replacement therapy.

Galactosemia

  • Patho: Deficiency in enzymes that break down galactose

  • Signs/symptoms: Jaundice, vomiting, feeding problems in newborns, intellectual disability if untreated. Requires a strict lactose-free diet.

Alkaptonuria

  • Patho: Deficiency of homogentisate oxidase; buildup of homogentisic acid

  • Signs/symptoms: Dark Urine, arthritis, dark pigmentation of connective tissue. Typically diagnosed in adulthood.

Phenylketonuria (PKU)

  • Patho: Deficiency of phenylalanine hydroxylase enzyme

  • Signs/symptoms: Intellectual disability if untreated, musty odor, seizures, lighter skin/hair. Requires a low-phenylalanine diet.

Klinefelter’s Syndrome

  • Patho: Extra X Chromosome (XXY)

  • Signs/symptoms: Tall, small testes, infertility, possible learning difficulties. May benefit from testosterone therapy.

Turner’s Syndrome

  • Patho: Missing or incomplete X Chromosome (XO)

  • Signs/symptoms: Short stature, webbed neck, infertility, heart defects. Often treated with growth hormone and estrogen therapy.

Hemophilia A vs Hemophilia B

  • Patho: A: Deficiency of factor VIII, B: Deficiency of factor IX (Christmas Disease)

  • Signs/symptoms: Easy bleeding, prolonged bleeding after injury, spontaneous joint bleeds. Treated with factor replacement therapy.

Fabry’s Disease

  • Patho: Deficiency of alpha-galactosidase A; buildup of glycolipids

  • Signs/symptoms: Pain (especially in hands and feet), kidney failure, heart problems, skin rash(angiokeratomas). Enzyme replacement therapy is available.

Wilson’s Disease

  • Patho: Defective copper excretion; copper buildup in organs

  • Signs/symptoms: liver disease, neurological symptoms (tremors, psychiatric changes), Kayser-Fleischer rings in eyes. Treated with copper-chelating agents.

Milroy’s disease

  • Patho: Genetic form of primary lymphedema

  • Signs/symptoms: swelling, mainly in legs, often starts in infancy. Typically managed with compression therapy.

INFECTIONS AND EXPOSURE CAUSING CONGENITAL DISORDERS

HIV/AIDS

  • Patho: Virus can cross placenta or be transmitted during delivery/breast feeding, leading to immune deficiency in infants. Use of antiretroviral therapy during pregnancy significantly reduces transmission risk.

Syphilis

  • Patho: Crosses placenta, causes stillbirth, bone deformities, hearing loss, and rash in newborns. Babies usually will be born blind. Preventable with timely prenatal screening and treatment.

Chlamydia

  • Patho: Eye infections (conjunctivitis) or pneumonia in newborns if transmitted during delivery. Preventable with maternal screening and treatment.

Gonorrhea

  • Patho: Eye infections(neo natal conjunctivitis Can lead to blindness) if transmitted during vaginal birth. Preventable with maternal screening and treatment, as well as prophylactic eye drops for newborns.

Chickenpox (Varicella)

  • Patho: If mother is infected early in pregnancy, can cause limb abnormalities, eye defects, and brain damage- encephalitis (congenital varicella syndrome). Vaccination is key for prevention if the mother is not immune.

Fetal Alcohol Syndrome (FAS)

  • Patho: Alcohol exposure interferes with fetal brain development

  • S/S: Growth problems, facial abnormalities (Thin upper lip), learning disabilities, behavioral issues. There are no safe levels of alcohol consumption during pregnancy.

German Measles (Rubella)

  • Patho: High risk of birth defects like heart disease, deafness, cataracts, and intellectual disabilities if infection occurs during early pregnancy. Vaccination is highly effective for prevention.

Arnold-Chiari Deformity

  • Patho: Part of the brain (the cerebellum and brainstem) gets pushed down through the foramen magnum (the hold at the bottom of the skull). This happens because the skull is too small or abnormally shaped

  • Signs/symptoms: Headaches (especially at the back of the head), neck pain, balance problems, dizziness, muscle weakness, numbness in hands and feet, sometimes trouble swallowing or breathing issues. Can be diagnosed with MRI.

Hydrocephalus

  • Patho: Buildup of cerebral fluid (CSF) in the brain’s ventricles, increasing pressure inside the skull

  • Signs/symptoms: In babies: rapid head growth, bulging soft spot (fontanelle), vomiting, sleepiness. In older children/adults: headaches, vision problems, balance issues, cognitive difficulties. Often requires shunt placement to drain excess fluid.

Spina Bifida

  • Patho: A neural tube defect where the spinal column doesn’t close completely during early fetal development. It can range from very mild(hidden) to severe (open spinal cord exposure)- Signs/symptoms: weakness/paralysis in legs, bowel/bladder problems, visible back

    • Spina Bifida Occulta: mildest form, a small gap in the spine but no opening or sac. Often no symptoms; may have a dimple, birthmark or small tuft of hair over the defect

    • SB Cystica: More severe, visible sac or cyst protrudes from the spine. Varies: include two subtypes- Meningocele: sac contains meninges but not the spinal cord itself: May have minor disabilities or no major symptoms if repaired early

      • Myelocele: protrusion of only the spinal cord

      • Myelomeningocele: Most serious form- the sac contains both meninges and spinal cord/nerves- Significant motor and sensory deficits, paralysis, bowel/bladder incontinence, high risk of hydrocephalus

Cerebral Palsy

  • Patho: Brain injury or abnormal brain development (before, during, or shortly after birth) affects movement, muscle tone, and posture

  • Signs/symptoms: muscle stiffness (spasticity) or floppiness, poor coordination, delayed motor milestones (like walking), abnormal reflexes, possible speech and cognitive issues. Management includes physical, occupational, and speech therapy.

Hirschsprungs Disease

  • Patho: Missing nerve cells (ganglion cells) in part of the large intestine- the bowel can’t relax and pass stool properly. This causes a blockage and problems with digestion

  • Signs/symptoms: Newborns: failure to pass meconium (first stool) within 48 hours, abdominal swelling, vomiting. Older children: chronic constipation, poor growth, severe belly distention. Requires surgical removal of the affected segment.

Klippel-Feil Syndrome

  • Patho: Congenital fusion of two or more cervical vertebrae (bones in the neck) due to improper development of the spinal column during early fetal life

  • Signs/symptoms: Short neck, low hairline at the back of the head, limited neck movement. Some may also have scoliosis, hearing loss, or heart/kidney defects. Management is typically supportive.

Sprengel’s Deformity

  • Patho: Congenital elevation of the scapula (shoulder blade) because it fails to descend into the correct position during fetal development

  • Signs/symptoms: One shoulder sits higher than the other, reduced shoulder movement, possible neck webbing, cosmetic asymmetry. In severe cases, it can also impact strength or arm function. Treatment includes physical therapy and, in some cases, surgery.

Cardiovascular System

Pericarditis

  • Patho: Inflammation of the pericardium, often due to infection, autoimmune issues, or after a heart attack. It causes sharp chest pain that gets worse when lying down and eases when leaning forward.

  • Signs/symptoms: Other signs include fever and pericardial friction rub. Treatment usually involves anti-inflammatory medications.

Left vs. Right Heart Failure

  • Patho: Left-sided heart failure happens when the left ventricle can’t pump blood properly, causing fluid backup in the lungs (shortness of breath, fatigue). Right-sided failure leads to systemic congestion, causing leg swelling, liver enlargement, and abdominal discomfort.

Cardiac Tamponade

  • Patho: A buildup of fluid in the pericardial sac compresses the heart, impairing filling and output.

Key signs: Hypotension, muffled heart sounds, and jugular vein distension (Beck’s triad)

Endocarditis

  • Patho: Infection of the heart’s inner lining, typically bacterial.

  • Signs/symptoms: Symptoms include fever, heart murmurs, fatigue, and signs of emboli like petechiae or splinter hemorrhages. Requires prolonged antibiotic treatment.

Myocarditis

  • Patho: Inflammation of the heart muscle, often viral.

  • Signs/symptoms: Presents with chest pain, arrhythmias, fatigue, and signs of heart failure in severe cases. Management includes supportive care and, in some cases, immunosuppressants.

Rheumatic Fever

  • Patho: An autoimmune response to a streptococcal infection. It mainly affects the joints, heart, skin, and brain.

  • Signs/symptoms: Symptoms: joint pain/swelling, fever, rash, and possible heart murmurs from valve damage. Prevention involves prompt treatment of strep throat.

Myocardial Infarction (MI)

  • Patho: Occurs when a coronary artery is blocked, leading to heart muscle death.

  • Signs/symptoms: Classic signs: crushing chest pain, shortness of breath, nausea, sweating. Requires immediate intervention to restore blood flow.

Angina Pectoris: Stable vs. Unstable

  • Stable angina: happens predictably with exertion and resolves with rest.

  • Unstable angina: is unpredictable, occurs at rest, and signals a higher risk of MI.

Thrombophlebitis

  • Patho: Inflammation and clot formation in a vein, usually in the legs.

  • Signs/symptoms: Symptoms include redness, swelling, warmth, and tenderness along the vein. Treatment involves anticoagulants and compression.

Cerebrovascular Accident (CVA)

  • Stroke, caused by interrupted blood flow to the brain.

  • Signs/symptoms: Signs: sudden weakness, facial drooping, difficulty speaking, loss of balance. Requires immediate medical attention to minimize brain damage.

Varicose Veins

  • Patho: Dilated, twisted veins from valve failure.

  • Signs/symptoms: Symptoms: visible veins, aching legs, swelling, and heaviness. Management includes compression stockings and, in some cases, surgical intervention.

Transient Ischemic Attacks (TIAs)

  • Brief, stroke-like attack that, unlike a stroke, lasts only a few minutes and doesn't cause