Genetics and Chromosome Disorders Quiz

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Questions and Answers

What does the term 'phenotype' refer to?

The outward appearance due to both genotype and environment (correct)

The genetic composition of an individual organism

Having inherited two identical alleles

An alternative form of a gene

Which syndrome is characterized by the presence of an extra X chromosome in males?

cri du chat syndrome

Turner syndrome

Down syndrome

Klinefelter syndrome (correct)

Which of the following is a common symptom of meningitis?

Demyelination of nerve fibers

Characteristic cry of the cat

Delayed age of onset

Severe throbbing headache (correct)

What causes encephalitis in most common cases?

Viral infections, particularly from mosquitoes or herpes simplex 1 Signup and view all the answers

Which statement is true regarding Down syndrome?

It is characterized by Trisomy 21. Signup and view all the answers

What sign is indicated by neck pain and increased rigidity upon passive neck flexion?

Brudzinski sign Signup and view all the answers

What is a characteristic feature of Huntington disease?

It is an autosomal dominant disorder with delayed onset. Signup and view all the answers

Which genetic disease is characterized by a distinctive cry compared to typical infants?

cri du chat syndrome Signup and view all the answers

What best describes the etiology of multiple sclerosis?

Unknown causes with an immune-mediated component Signup and view all the answers

Which of the following is NOT a common cause of meningitis?

Genetic mutations Signup and view all the answers

What is the most common cause of traumatic intracranial mass lesions?

Subdural hematoma Signup and view all the answers

Which age group is most commonly affected by epidural hematoma?

Adults aged 20-40 Signup and view all the answers

What symptom is most commonly associated with grade 1-2 spondylolisthesis?

Pain in the lower back and buttocks Signup and view all the answers

What condition is characterized by compression of nerve roots below L1?

Cauda equina syndrome Signup and view all the answers

Which of the following is a symptom of spinal stenosis?

Tingling in extremities Signup and view all the answers

Which risk factor significantly increases the likelihood of having a stroke?

Poorly controlled arterial hypertension Signup and view all the answers

What type of hematoma occurs between the dura mater and the skull?

Epidural hematoma Signup and view all the answers

What condition involves the sliding of a vertebra anteriorly due to an osseous defect?

Spondylolisthesis Signup and view all the answers

Which acquired condition might lead to spinal stenosis?

Bulging disk Signup and view all the answers

What is a common symptom of herniated nucleus pulposus?

Referred pain to a segmental area Signup and view all the answers

Study Notes

Genetic Terms

Heterozygous: Having inherited different alleles of a gene.
Homozygous: Having inherited two identical alleles of a gene.
Genotype: The genetic makeup of an individual organism.
Phenotype: The observable characteristics of an individual organism, influenced by both genotype and environment.
Allele: One of two or more alternative forms of a gene, arising from mutations.

Chromosome Disorders

Klinefelter Syndrome:
- Occurs in males with an extra X chromosome (XXY).
- Affects approximately 1 in 1,000 male births.
- Individuals have a male appearance but are usually sterile.
- 50% develop gynecomastia (breast development in males).
Down Syndrome:
- Also known as Trisomy 21, characterized by an extra copy of chromosome 21.
- Affects approximately 1 in 800-1000 live births.
- Most males are sterile, while some females are able to reproduce.
- Individuals have distinctive facial features.
Turner Syndrome:
- Occurs in females with a missing or partially missing X chromosome.
- Affects approximately 1 in 2,000-2,500 live female births.
Cri du Chat Syndrome:
- Characterized by a missing piece of chromosome 5.
- Affected infants have a distinctive cry that sounds like a cat's meow.
- Occurs in approximately 1 in 20,000-50,000 newborns.

Genetic Diseases

Huntington Disease:
- An autosomal dominant neurologic disorder affecting approximately 1 in 10,000 people.
- Onset typically occurs between 30-40 years of age.

Meningitis

Inflammation of the brain or spinal cord.
Infectious meningitis can be caused by:
- Bacteria
- Viruses
- Fungi
- Parasites
- Toxins
Infection types: acute, subacute, or chronic.
Symptoms:
- Severe throbbing headache
- Severe photophobia (sensitivity to light)
- Nuchal rigidity (neck stiffness)
- Positive Kernig and Brudzinski signs.

Kernig Sign

Pain in the back and neck regions when straightening the knee with the hip and knee flexed.

Brudzinski Sign

Neck pain and increased rigidity when passively flexing the neck.

Encephalitis

Acute inflammation of the brain, typically of viral origin.
Most common causes:
- Bites of mosquitos, ticks, or flies
- Herpes simplex 1
May arise from:
- Complications of systemic viral diseases.
- Post-viral infection recovery.
- Following vaccination with a live attenuated virus vaccine.
- Typhus
- Trichinosis
- Malaria
- Schistosomiasis (tropical virus)

Multiple Sclerosis

Chronic immune-mediated inflammatory disease affecting the central nervous system.
Involves demyelination, scarring, and loss of axons.
Etiology is unknown.
Onset typically between 20-40 years of age.
Risk factors (inconclusive):
- Environmental:
  - Smoking
  - Vitamin D deficiency
  - Obesity
  - Infection (e.g. Epstein-Barr virus)
- Genetic factors

Subdural Hematoma

Bleeding between the dura mater and arachnoid membrane.
Caused by tearing of veins.
Most common cause of traumatic intracranial mass lesions.
Forceful impact:
- Vehicular accidents or falls
- Particularly common in older adults and alcoholics.

Epidural Hematoma

Bleeding between the dura mater and the skull.
Represents 1-2% of major head injuries.
Occurs in all age groups, most common in 20-40 year olds.
Causes:
- Vehicular accidents
- Minor falls
- Sporting accidents
Most common site: temporal fossa.

Spondylolisthesis

Osseous defect of the pars interarticularis.
Allows a vertebra to slide anteriorly in relation to the vertebra below.
Commonly occurs at L5-S1.
Graded from 1-4 based on the percentage of slippage:
- Grade 1-2:
  - Symptoms of lower back and buttock pain.
  - Muscle spasms in the lower back and legs.
  - Tightened hamstrings.
  - Management: Exercise, rest, back bracing.
- Grade 3-4: Usually requires surgical intervention.

Cauda Equina Syndrome

Compression of nerve roots below L1.
Causes:
- Fracture and dislocation of the spine.
- Large posterocentral intervertebral disc herniation.
Symptoms:
- Lower extremity motor deficits.
- Variable sensorimotor dysfunction.
- Variable reflex dysfunction.
- Variable bladder, bowel, and sexual dysfunction.

Herniated Nucleus Pulposus

No intrinsic innervation (nerve supply).
When herniated through a prolapsed disk, it irritates the spinal nerve and causes pain referred to the segmental area.

Spinal Stenosis

Narrowing of the spinal canal.
Causes pressure on the spinal nerves or cord.
Can be congenital or acquired (more common).
Associated with trauma or arthritis.
Categorized by the affected area of the spine:
- Cervical
- Thoracic
- Lumbar
Acquired conditions:
- Bulging disk
- Facet hypertrophy
- Thick, ossified posterior longitudinal ligament.
Symptoms:
- Related to the affected area of the spine.
- Pain
- Numbness
- Tingling in neck/extremities
- Weakness
- Difficulty walking.
Surgical decompression recommended for individuals with chronic symptoms.

Cerebral Vascular Accident (Stroke)

Causes:
- Blocked artery (ischemic stroke).
- Leaking or bursting of a blood vessel (hemorrhagic stroke).
Risk Factors:
- Poorly controlled or uncontrolled arterial hypertension.
- Smoking (increases risk by 2-4 times).
- Insulin resistance and diabetes mellitus.
- Atrial fibrillation (A-fib).
- Polycythemia (excess red blood cells).
- Thrombocytopenia (excess platelets).
- High total cholesterol or low high-density lipoprotein (HDL) cholesterol.
- Congestive heart disease/peripheral vascular disease.
- Hyperhomocysteinemia.
- Sickle cell disease.
- Postmenopausal hormone therapy.
- High sodium intake (>2300 mg); Low potassium intake.

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Description

Test your knowledge on key genetic terms and chromosome disorders such as Klinefelter Syndrome and Down Syndrome. This quiz covers definitions and characteristics essential for understanding genetic variations and their implications. Perfect for students studying genetics or biology.