Question: What is (are) Parkinson disease ?
Answer: Parkinson disease belongs to a group of conditions called movement disorders. The four main symptoms are tremor, or trembling in hands, arms, legs, jaw, or head; rigidity, or stiffness of the limbs and trunk; bradykinesia, or slowness of movement; and postural instability, or impaired balance. These symptoms usually begin gradually and worsen with time. As they become more pronounced, patients may have difficulty walking, talking, or completing other simple tasks. Not everyone with one or more of these symptoms has Parkinson disease, as the symptoms sometimes appear in other diseases as well. Parkinson disease affects about 1 to 2 percent of people over the age of 60 years and the chance of developing Parkinson disease increases as we age. Although some Parkinson disease cases appear to be hereditary most cases are sporadic and occur in people with no apparent history of the disorder in their family. When three or more people are affected in a family, especially if they are diagnosed at an early age (under 50 years) there may be a gene making this family more likely to develop the condition. Currently, seven genes that cause some form of Parkinson's disease have been identified. Mutations (changes) in three known genes called SNCA (PARK1),UCHL1 (PARK 5), and LRRK2 (PARK8) and another mapped gene (PARK3) have been reported in families with dominant inheritance. Mutations in three known genes, PARK2 (PARK2), PARK7 (PARK7), and PINK1 (PARK6) have been found in affected individuals who had siblings with the condition but whose parents did not have Parkinson's disease (recessive inheritance). There is some research to suggest that these genes are also involved in early-onset Parkinson's disease (diagnosed before the age of 30) or in dominantly inherited Parkinson's disease but it is too early yet to be certain. However, in most cases inheriting a mutation will not cause someone to develop Parkinson's disease because there may be additional genes and environmental factors determining who will get the condition, when they get it and how it affects them.
Source: GARD

Question: What are the symptoms of Parkinson disease ?
Answer: What are the signs and symptoms of Parkinson disease? A number of disorders can cause symptoms similar to those of Parkinson disease. People with symptoms that resemble Parkinson disease but that result from other causes are sometimes said to have parkinsonism. Some of these disorders are listed below. Postencephalitic parkinsonism Drug-induced parkinsonism Toxin-induced parkinsonism Arteriosclerotic parkinsonism Parkinsonism-dementia complex of Guam Post-traumatic parkinsonism Essential tremor Normal pressure hydrocephalus Progressive supranuclear palsy Corticobasal degeneration Multiple system atrophy Dementia with Lewy bodies More information on each of these conditions is available in the National Institute of Neurological Disorders and Stroke (NINDS) publication, Parkinson's Disease: Hope Through Research. Parkinsonian symptoms may also appear in patients with other, clearly distinct neurological disorders such as Wilson disease, Huntington disease, Alzheimer disease, spinocerebellar ataxias, and Creutzfeldt-Jakob disease. Each of these disorders has specific features that help to distinguish them from Parkinson disease. The Human Phenotype Ontology provides the following list of signs and symptoms for Parkinson disease. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Dysautonomia 7.5% Hallucinations 7.5% Bradykinesia - Constipation - Dementia - Depression - Dysarthria - Dysphagia - Dystonia - Insidious onset - Lewy bodies - Mask-like facies - Neuronal loss in central nervous system - Parkinsonism - Personality changes - Postural instability - Progressive - Resting tremor - Rigidity - Short stepped shuffling gait - Sleep disturbance - Substantia nigra gliosis - Urinary urgency - Weak voice - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
Source: GARD

Question: What causes Parkinson disease ?
Answer: What causes Parkinson disease? Parkinson disease occurs when the nerve cells in the brain that make dopamine, a chemical messenger which transmits signals within the brain to produce smooth physical movements, are slowly destroyed. Without dopamine, the nerve cells in the part of the brain known as the substantia nigra cannot properly send messages. This leads to progressive loss of muscle function. Exactly why these brain cells waste away is unknown. Recent studies have shown that people with Parkinson disease also experience damage to the nerve endings that produce the neurotransmitter norepinephrine. Norepinephrine, which is closely related to dopamine, is the main chemical messenger of the sympathetic nervous system, the part of the nervous system that controls the automatic functions of the body, including pulse and blood pressure. The loss of norepinephrine may explain some of the non-motor features seen in Parkinson disease, including fatigue and problems with blood pressure regulation. More detailed information about the cause of Parkinson disease is available through an information page developed by the National Institute of Neurological Disorders and Stroke (NINDS). Click here to view this information.
Source: GARD

Question: Is Parkinson disease inherited ?
Answer: Is Parkinson disease inherited? Most cases of Parkinson disease are classified as sporadic and occur in people with no apparent history of the disorder in their family. Although the cause of these cases remains unclear, sporadic cases probably result from a complex interaction of environmental and genetic factors. Additionally, certain drugs may cause Parkinson-like symptoms. Approximately 15 percent of people with Parkinson disease have a family history of the disorder. These familial cases are caused by mutations in the LRRK2, PARK2, PARK7, PINK1, or SNCA gene, or by alterations in genes that have not yet been identified. Mutations in some of these genes may also play a role in cases that appear to be sporadic. It is not fully understood how mutations in the LRRK2, PARK2, PARK7, PINK1, or SNCA gene cause Parkinson disease. Some mutations appear to disturb the cell machinery that breaks down (degrades) unwanted proteins. As a result, un-degraded proteins accumulate, leading to the impairment or death of dopamine-producing neurons. Other mutations may involve mitochondria, the energy-producing structures within cells. As a byproduct of energy production, mitochondria make unstable molecules, called free radicals, that can damage the cell. Normally, the cell neutralizes free radicals, but some gene mutations may disrupt this neutralization process. As a result, free radicals may accumulate and impair or kill dopamine-producing neurons. In some families, alterations in the GBA, SNCAIP, or UCHL1 gene appear to modify the risk of developing Parkinson disease. Researchers have identified some genetic changes that may reduce the risk of developing the disease, while other gene alterations seem to increase the risk.
Source: GARD

Question: How to diagnose Parkinson disease ?
Answer: How is Parkinson disease diagnosed? There are currently no blood or laboratory tests that have been proven to help diagnose sporadic cases of Parkinson disease. The diagnosis is generally made after careful evaluation of medical history, current symptoms, and exclusion of other conditions. The clinical findings of tremor, rigidity, and bradykinesia are highly suggestive of Parkinson disease. The genetic cause of some forms of Parkinson disease has been identified. In those cases, genetic testing may be utilized to identify affected family members.
Source: GARD