Genetics of Neurofibromatosis Quiz

Loss of myelin sheath around nerve fibers. This affects the nerve's ability to transmit signals.

Damage to the axons of nerve cells. This often leads to progressive loss of axons.

Reduced signal amplitude (lower signal strength) due to lost axons in peripheral nerves, despite relatively normal conduction speed.

Sudden damage to the myelin sheaths surrounding nerve fibers. Usually affecting isolated segments of the nerve internodes.

Patterns of injury in peripheral nerve fibers: normal axons in motor units are arranged checkerboard style, acute axons lose distal parts and myelin, and acute demyelinating disease targets myelin segments, sparing axons

Regrowth of damaged axons; myelination occurs with Schwann cells but the new myelin, while functioning, may be shorter and thinner, compared to original.

Degeneration of longer axons first, in cases of toxic or metabolic insults; like a chain reaction, starting from the long ends and progressively deteriorating towards the core.

A progressive brain disorder characterized by plaque and tangle accumulation, leading to cognitive decline and dysfunction.

Abnormal protein aggregates in the brain associated with Alzheimer's Disease.

The process of development of Alzheimer's disease.

Increasing difficulties with judgment, thinking, problem-solving, communication, daily living, swallowing, and weight loss. Personality and behavioral changes also occur.

Dementia caused by disrupted blood flow to the brain.

Include difficulties with memory, thinking, behavior, reading, writing, interest, personality, planning, attention, calculations, problem-solving, and possibly visual issues and motor skill impairments.

A group of brain disorders causing progressive decline in memory and other cognitive abilities.

Vascular dementia can occur alone or with other types of dementia, such as Alzheimer's.

Gradual emergence of memory, visuospatial, judgment, personality and language deficits, leading to severe disability, muteness, and immobility over a 5-10 year period.

Episodes of worsening neurological symptoms in Multiple Sclerosis (MS).

A gradual worsening of neurological function in MS patients.

Inflammation of the optic nerve, causing visual problems.

Neurodegenerative disorder impacting movement and often leading to dementia.

Lower than normal levels of dopamine in the brain.

Abnormal protein deposits found in the brain.

Group of structures within the brain controlling movement.

Autoimmune disease that damages myelin in the CNS.

Damage to the insulating layer (myelin) of nerve cells in the central nervous system.

Symptoms in Parkinson's Disease affecting movement.

An autoimmune disease where antibodies attack acetylcholine (ACh) receptors at the neuromuscular junction, leading to muscle weakness.

Antibodies that target and damage acetylcholine receptors, interfering with nerve signal transmission at the neuromuscular junction.

A protein found on the muscle surface that helps regulate ACh receptor function.

Immune system response where antibodies trigger the destruction of cells or tissues by complement proteins.

A tumor of the thymus gland, often associated with myasthenia gravis.

Symptoms of myasthenia gravis include fluctuating weakness, worsening with exertion, diplopia (double vision), ptosis (drooping eyelids), and generalized weakness.

Tests that assess the electrical activity of nerves and muscles to help diagnose myasthenia gravis.

A characteristic finding in electrophysiologic studies of myasthenia gravis where muscle response weakens with repeated nerve stimulation.

A systemic autoimmune disease that affects muscles and skin, causing weakness, inflammation, and skin rashes.

Weakness in the muscles closer to the center of the body, such as the shoulders and hips.

A change in the NF1 gene causes Neurofibromatosis type 1. It's a loss-of-function mutation, meaning the gene doesn't work properly.

A protein encoded by the NF1 gene. It acts as a tumor suppressor, helping to control cell growth and development.

Tumors caused by the NF1 gene mutation. These tumors lack neurofibromin, leading to uncontrolled cell growth.

The NF2 gene is located on chromosome 22q12. It's also commonly mutated in sporadic meningiomas and schwannomas.

A genetic disorder caused by mutations in the NF2 gene. It is less common than NF1, affecting about 1 in 40,000 to 50,000 people.

A brain injury that occurs on the same side of the impact, usually when the head is immobile at the time of trauma.

A brain injury that occurs on the opposite side of the impact, typically when the head is mobile and recoils after the initial impact.

Conditions affecting the brain due to impaired blood flow, leading to tissue damage and potentially stroke.

A clinical term for a cerebrovascular event causing neurologic symptoms that persist beyond 24 hours.

A stroke caused by blockage of a cerebral artery, depriving brain tissue of blood.

A stroke caused by bleeding into the brain tissue due to a ruptured blood vessel.

A temporary neurological deficit caused by a temporary disruption of blood flow to the brain, usually lasting less than 24 hours.

Collagen acts as a 'glue' in the body, providing strength and elasticity to connective tissue.

A group of genetic disorders affecting collagen production, leading to weakened connective tissues.

Symptoms vary depending on the type of EDS, but commonly involve joint hypermobility, stretchy skin, and fragile blood vessels.

A type of malignant bone tumor characterized by primitive round cells.

Most commonly found in the long bones, particularly the thighbone (femur) and pelvis.

Painful swelling in the affected area, fever, weight loss, and elevated blood cell counts.

X-rays show a destructive tumor with 'moth-eaten' edges that spread into surrounding tissues.

The gene associated with Ewing sarcoma, encoding a protein that controls growth and differentiation.

Most often diagnosed between the ages of 5 and 25, and it's the second most common malignant bone tumor in children.

Frequently found in the spine, pelvis, chest, and limbs, with long bone diaphyses being the most common.

A chronic inflammatory disease that primarily affects the spine, causing inflammation and fusion of the joints, leading to stiffness and limited mobility.

Low back pain that improves with exercise but not rest, severe morning stiffness lasting over 3 months, back pain at night, limited spinal movement, loss of lumbar curve, and possible inflammation in other joints like hips, knees, and shoulders.

About 90% of people with Ankylosing Spondylitis are positive for the HLA-B27 gene. The exact role of this gene in causing the disease is unknown, but it seems linked to presenting specific antigens that may trigger the immune response.

EDS affects tissues rich in collagen, like skin, ligaments, and joints. This leads to hypermobility (joints bending beyond normal range) and hyperextensibility (skin stretching excessively).

A type of EDS characterized by stretchy skin, hypermobile joints, and often accompanied by other issues like kyphoscoliosis (curvature of the spine) and digestive problems.

A spinal deformity involving both kyphosis (hunchback) and scoliosis (sideways curvature) often seen in individuals with Classic EDS.

A specific type of EDS with extremely loose joints and stretchy skin, often leading to dislocations and joint instability.

The fragile tissues in EDS are a result of faulty collagen, which lacks proper tensile strength. The body cannot properly build and maintain strong, supportive tissues.

Individuals with EDS have a defect in their connective tissue, which supports many body parts like skin, muscles, and ligaments. This leads to fragile skin and unstable joints.

A brain disorder characterized by recurrent seizures caused by abnormal neuron activity.

Certain stimuli that can initiate a seizure. Common examples include flashing lights, fever, and loud noises.

A type of seizure where abnormal electrical activity affects the entire brain surface.

A type of seizure confined to one hemisphere where consciousness remains intact.

Cells responsible for breaking down bone tissue. They attach to the matrix, create a sealed pit, and secrete acids and enzymes to dissolve bone components.

Cells responsible for building bone tissue. They synthesize, transport, and assemble matrix components, regulating bone mineralization.

A type of seizure confined to one hemisphere where consciousness is altered.

Joints that allow for a wide range of motion. They are found between bones formed by endochondral ossification, contain a joint space, and are strengthened by ligaments and muscles.

A life-threatening condition characterized by a series of seizures without recovery between episodes.

The most important structure in a synovial joint, composed of water, collagen, proteoglycans, and chondrocytes. Its primary function is to protect bone surfaces and provide a smooth, lubricated surface for joint movement.

These molecules, released by various cells, initiate degradative processes in articular cartilage. This can lead to damage and contribute to joint diseases.

Deposits of aggregated Aβ peptides in the brain that contribute to Alzheimer's disease.

Aggregated microtubule binding protein tau that develop intracellularly and extracellularly after neuronal death, contributing to Alzheimer's disease.

A traumatic brain injury (TBI) diagnosis is best made at the time of injury or within the first 24 hours.

Level of consciousness (LOC) is a sensitive indicator of altered brain function. Changes in alertness and attentiveness to one's environment are key signs.

Pupil reflexes indicate the function of the brainstem and cranial nerves (CN) II and III. Changes in size, shape, and reactivity are early indicators of increased intracranial pressure (ICP) and possible brain herniation.

The Glasgow Coma Scale (GCS) is a standardized tool for assessing LOC in acutely brain-injured persons. It assigns numeric scores based on eye opening, verbal responses, and motor reactions.

The corneal reflex is elicited by touching the cornea with a wisp of cotton. A blink response indicates normal function, while an absence of a blink suggests severely impaired brain function.

The body creates vitamin D from a precursor (7-dehydrocholesterol) through a photochemical reaction triggered by UVB radiation from sunlight or specific artificial light.

The form of vitamin D synthesized in the skin, also known as vitamin D3.

A bone disease in adults characterized by inadequate bone mineralization, leading to soft, weak bones.

Insufficient vitamin D, calcium, or phosphorus, poor vitamin D metabolism, or kidney disease can cause osteomalacia.

A bone disease affecting children, characterized by soft, weak bones due to failure of bone mineralization.

Some forms of rickets are linked to genetic defects in vitamin D synthesis or its receptor (VDR).

Osteomalacia symptoms include: back pain, bowing legs, and increased fracture risk.

Rickets symptoms include: deformities like bowing legs, skull deformities, and delayed bone development.

Vitamin D acts on the kidneys, intestines, and bones to increase calcium and phosphate levels in the blood.

When vitamin D is low, calcium levels decrease, triggering an increase in PTH (parathyroid hormone) to compensate for the low calcium.

A type of bone infection caused by bacteria entering the bloodstream from another infection.

Hematogenous osteomyelitis commonly affects children due to their developing immune system and bone structure.

Initial symptoms often include general fatigue, body aches, and malaise.

Joint swelling, warmth, and pain develop weeks to months after initial symptoms.

Hematogeous osteomyelitis often affects joints on both sides of the body in a mirror-like pattern.

Over time, the affected joints can become enlarged, lose range of motion, and experience chronic inflammation.

An autoimmune disease causing chronic inflammation of the joints, leading to pain, swelling, and joint damage.

A destructive layer of inflamed tissue forming in rheumatoid arthritis, eroding articular cartilage and causing bone damage.

Reduced bone density, making bones weaker and more susceptible to fractures.

Severe osteopenia, significantly increasing the risk of fractures.

A chronic bone disease resulting in abnormal bone growth: faster breakdown then formation, leading to thicker, softer bones.

Paget's disease prevalence varies drastically across different regions. It's common in England, France, etc. but rare in Scandinavia, China, and Africa.

Localized pain in the bones due to bone overgrowth or microfractures and compression of spinal and cranial nerves.

Sarcoma, a type of cancer, develops in the bones affected by Paget's disease.

X-rays reveal thick, coarsened bone cortices and medulla. Elevated alkaline phosphatase levels in the blood are typical.

A birth defect where the spinal cord doesn't close completely during pregnancy, ranging from a mild bony defect to a severe malformation with exposed spinal cord.

A group of birth defects that occur when the neural tube, the structure that develops into the brain and spinal cord, doesn't close completely during pregnancy.

A severe birth defect where a major portion of the brain and skull are missing.

A type of neural tube defect where spinal cord tissue protrudes through a gap in the spine.

A birth defect where brain tissue protrudes through a gap in the skull.

A progressive neurodegenerative disease that affects nerve cells in the brain and spinal cord, leading to muscle weakness, difficulty speaking, and eventually paralysis.

ALS involves the loss of upper and lower motor neurons in the brain and spinal cord, often accompanied by the buildup of toxic proteins.

Individuals with Spina Bifida may have motor and sensory deficits in the lower extremities, bowel and bladder control problems, and are vulnerable to infections due to weakened skin barriers.

The frequency of neural tube defects varies between ethnic groups. The overall recurrence rate for a neural tube defect in subsequent pregnancies is estimated at 4% to 5%.

A traumatic brain injury (TBI) diagnosis is most accurately made at the time of injury or within the first 24 hours.

Level of consciousness (LOC) refers to a person's alertness and attentiveness to their environment. Changes in LOC are a sensitive indicator of altered brain function.

Pupil reflexes reflect the function of the brainstem and cranial nerves II and III. Changes in pupil size, shape, and reactivity can be early indicators of increased intracranial pressure (ICP) or a brain herniation.

The Glasgow Coma Scale (GCS) is a standardized tool used to assess the level of consciousness in acutely brain-injured patients. It assigns numeric scores based on eye opening, verbal responses, and motor reactions.

The corneal reflex is tested by lightly touching a wisp of cotton to the cornea. A normal response is a blink, while an absence of a blink can indicate severely impaired brain function.

Initially, a stroke causes flaccidity or paralysis. As recovery progresses, spasticity develops.

Stroke symptoms affect the opposite side of the body from the brain region affected.

Active and passive range of motion exercises are crucial even in the acute phase of stroke recovery.

To reduce swelling after a stroke, elevate the affected limb, use compression stockings, and ensure proper body alignment.

Sensory disturbances mirror the motor paralysis, potentially including neglect and visual impairments.

A stroke can cause blindness in the same side of the visual field in both eyes, called contralateral hemianopsia.

Years after brain injury, various neurological syndromes can arise, including posttraumatic hydrocephalus, chronic traumatic encephalopathy (CTE), epilepsy, and psychiatric disorders.

CTE, a dementing illness from repeated head trauma, leads to brain atrophy, enlarged ventricles, and tau protein buildup.

Seizures are caused by sudden, abnormal excessive electrical discharges in the brain.

Symptoms include fluctuating weakness, worsening with exertion, diplopia (double vision), ptosis (drooping eyelids), and generalized weakness. The disease can affect the muscles that control eye movement, facial expressions, swallowing, and breathing.

These tests assess the electrical activity of nerves and muscles. They reveal a decrement in muscle response with repeated nerve stimulation, a characteristic feature of MG.

A significant association exists between pathogenic anti-ACh receptor autoantibodies and thymic abnormalities. About 10% of patients with MG have a thymoma, a tumor of thymic epithelial cells.

Dermatomyositis often presents with proximal muscle weakness (weakness in the shoulders, hips, and thighs), skin changes like Gottron's papules and heliotrope rash, and possible internal organ involvement.

Cases with antibodies against muscle-specific receptor tyrosine kinase tend to have more focal muscle involvement (neck, shoulder, facial, respiratory, and bulbar muscles) in comparison to typical MG cases.

Antibodies against muscle-specific receptor tyrosine kinase do not fix complement. Instead, they interfere with the trafficking and clustering of ACh receptors within the muscle cell membrane, reducing ACh receptor function.

Epilepsy is a brain disorder characterized by recurrent seizures caused by abnormal neuron activity.

The two hallmark signs of Alzheimer's disease are amyloid plaques and neurofibrillary tangles.

The altered state of consciousness after an epileptic seizure.

Paget's disease is more common in certain geographic regions, particularly in Caucasians of England, France, Austria, and parts of Germany, Australia, New Zealand, and the United States. It is less prevalent in native populations of Scandinavia, China, Japan, and Africa.

In Paget's disease, bone matrices become thicker but disorganized and softer. This occurs due to an initial phase of excessive bone resorption by osteoclasts, followed by excessive bone formation by osteoblasts.

Paget's disease often presents with localized bone pain, due to microfractures or bone overgrowth. It can also lead to bone deformities, such as bowing of the femurs and tibiae, and cranial enlargement known as leontiasis ossea.

The most serious complication of Paget's disease is the development of sarcoma, usually osteosarcoma or fibrosarcoma, which can arise in Paget lesions in the long bones, pelvis, skull, and spine.

Paget's disease is diagnosed by radiographic examination, which typically reveals enlarged bones with thickened, coarsened cortices and medulla. Serum alkaline phosphatase levels are often elevated, while calcium and phosphate levels usually remain normal.