Wilson disease is a disorder of copper metabolism that, when untreated, can present with hepatic, neurologic, or psychiatric disturbances – or a combination of these – in individuals ages three years to older than 70 years. Manifestations in untreated individuals vary among and within families. Liver disease can include recurrent jaundice, simple acute self-limited hepatitis-like illness, autoimmune-type hepatitis, fulminant hepatic failure, or chronic liver disease. Neurologic presentations can include dysarthria, movement disorders (tremors, involuntary movements, chorea, choreoathetosis), dystonia (mask-like facies, rigidity, gait disturbance, pseudobulbar involvement), dysautonomia, seizures, sleep disorders, or insomnia. Psychiatric disturbances can include depression, bipolar disorder / bipolar spectrum disorder, neurotic behaviors, personality changes, or psychosis. Other multisystem involvement can include the eye (Kayser-Fleischer rings), hemolytic anemia, the kidneys, the endocrine glands, and the heart.

Waisman syndrome (WSMN) is an X-linked neurologic disorder characterized by delayed psychomotor development, impaired intellectual development, and early-onset Parkinson disease (summary by Wilson et al., 2014).

POLG-related disorders comprise a continuum of overlapping phenotypes that were clinically defined before the molecular basis was known. POLG-related disorders can therefore be considered an overlapping spectrum of disease presenting from early childhood to late adulthood. The age of onset broadly correlates with the clinical phenotype. In individuals with early-onset disease (prior to age 12 years), liver involvement, feeding difficulties, seizures, hypotonia, and muscle weakness are the most common clinical features. This group has the worst prognosis. In the juvenile/adult-onset form (age 12-40 years), disease is typically characterized by peripheral neuropathy, ataxia, seizures, stroke-like episodes, and, in individuals with longer survival, progressive external ophthalmoplegia (PEO). This group generally has a better prognosis than the early-onset group. Late-onset disease (after age 40 years) is characterized by ptosis and PEO, with additional features such as peripheral neuropathy, ataxia, and muscle weakness. This group overall has the best prognosis.

Individuals with X-linked dystonia-parkinsonism (XDP) have dystonia of varying severity and parkinsonism. XDP afflicts primarily Filipino men and, rarely, women. The mean age of onset in men is 39 years; the clinical course is highly variable with parkinsonism as the initial presenting sign, overshadowed by dystonia as the disease progresses. Features of parkinsonism include resting tremor, bradykinesia, rigidity, postural instability, and severe shuffling gait. The dystonia develops focally, most commonly in the jaw, neck, trunk, and eyes, and less commonly in the limbs, tongue, pharynx, and larynx, the most characteristic being jaw dystonia often progressing to neck dystonia. Individuals with pure parkinsonism have non-disabling symptoms that are only slowly progressive; those who develop a combination of parkinsonism and dystonia can develop multifocal or generalized symptoms within a few years and die prematurely from pneumonia or intercurrent infections. Female carriers are mostly asymptomatic, though a small minority may manifest dystonia, parkinsonism, or chorea.

LRRK2 Parkinson disease (PD) is characterized by features consistent with idiopathic PD: initial motor features of slowly progressive asymmetric tremor at rest and/or bradykinesia, cogwheel muscle rigidity, postural instability, and gait abnormalities that may include festination and freezing. Certain nonmotor symptoms in LRRK2-PD, especially REM sleep behavior disorder and cognitive decline, may occur at similar or slightly reduced frequency compared to typical idiopathic* PD. Onset is generally after age 50, although early-onset (in the 20s) and late-onset (in the 90s) disease has been described. * Idiopathic PD refers to the presence of signs and symptoms of PD for which the etiology is currently unknown and in which there is no known family history of PD.

Kufor-Rakeb syndrome is a rare autosomal recessive form of juvenile-onset atypical Parkinson disease (PARK9) associated with supranuclear gaze palsy, spasticity, and dementia. Some patients have neuroradiologic evidence of iron deposition in the basal ganglia, indicating that the pathogenesis of PARK9 can be considered among the syndromes of neurodegeneration with brain iron accumulation (NBIA; see 234200) (summary by Bruggemann et al., 2010). For a phenotypic description and a discussion of genetic heterogeneity of Parkinson disease (PD), see 168600. Biallelic mutation in the ATP13A2 gene also causes autosomal recessive spastic paraplegia-78 (SPG78; 617225), an adult-onset neurodegenerative disorder with overlapping features. Patients with SPG78 have later onset and prominent spasticity, but rarely parkinsonism. Loss of ATP13A2 function results in a multidimensional spectrum of neurologic features reflecting various regions of the brain and nervous system, including cortical, pyramidal, extrapyramidal, brainstem, cerebellar, and peripheral (summary by Estrada-Cuzcano et al., 2017).

Parkinson's disease is a progressive disorder of the nervous system. The disorder affects several regions of the brain, especially an area called the substantia nigra that controls balance and movement.\n\nGenerally, Parkinson's disease that begins after age 50 is called late-onset disease. The condition is described as early-onset disease if signs and symptoms begin before age 50. Early-onset cases that begin before age 20 are sometimes referred to as juvenile-onset Parkinson's disease.\n\nOften the first symptom of Parkinson's disease is trembling or shaking (tremor) of a limb, especially when the body is at rest. Typically, the tremor begins on one side of the body, usually in one hand. Tremors can also affect the arms, legs, feet, and face. Other characteristic symptoms of Parkinson's disease include rigidity or stiffness of the limbs and torso, slow movement (bradykinesia) or an inability to move (akinesia), and impaired balance and coordination (postural instability). These symptoms worsen slowly over time.\n\nParkinson's disease can also affect emotions and thinking ability (cognition). Some affected individuals develop psychiatric conditions such as depression and visual hallucinations. People with Parkinson's disease also have an increased risk of developing dementia, which is a decline in intellectual functions including judgment and memory.

GTP cyclohydrolase 1-deficient dopa-responsive dystonia (GTPCH1-deficient DRD) is characterized by childhood-onset dystonia and a dramatic and sustained response to low doses of oral administration of levodopa. This disorder typically presents with gait disturbance caused by foot dystonia, later development of parkinsonism, and diurnal fluctuation of symptoms (aggravation of symptoms toward the evening and alleviation of symptoms in the morning after sleep). Initial symptoms are often gait difficulties attributable to flexion-inversion (equinovarus posture) of the foot. Occasionally, initial symptoms are arm dystonia, postural tremor of the hand, or slowness of movements. Brisk deep-tendon reflexes in the legs, ankle clonus, and/or the striatal toe (dystonic extension of the big toe) are present in many affected individuals. In general, gradual progression to generalized dystonia is observed. Intellectual, cerebellar, sensory, and autonomic disturbances generally do not occur.

Parkinson's disease can also affect emotions and thinking ability (cognition). Some affected individuals develop psychiatric conditions such as depression and visual hallucinations. People with Parkinson's disease also have an increased risk of developing dementia, which is a decline in intellectual functions including judgment and memory.\n\nOften the first symptom of Parkinson's disease is trembling or shaking (tremor) of a limb, especially when the body is at rest. Typically, the tremor begins on one side of the body, usually in one hand. Tremors can also affect the arms, legs, feet, and face. Other characteristic symptoms of Parkinson's disease include rigidity or stiffness of the limbs and torso, slow movement (bradykinesia) or an inability to move (akinesia), and impaired balance and coordination (postural instability). These symptoms worsen slowly over time.\n\nGenerally, Parkinson's disease that begins after age 50 is called late-onset disease. The condition is described as early-onset disease if signs and symptoms begin before age 50. Early-onset cases that begin before age 20 are sometimes referred to as juvenile-onset Parkinson's disease.\n\nParkinson's disease is a progressive disorder of the nervous system. The disorder affects several regions of the brain, especially an area called the substantia nigra that controls balance and movement.

Parkinson's disease is a progressive disorder of the nervous system. The disorder affects several regions of the brain, especially an area called the substantia nigra that controls balance and movement.\n\nGenerally, Parkinson's disease that begins after age 50 is called late-onset disease. The condition is described as early-onset disease if signs and symptoms begin before age 50. Early-onset cases that begin before age 20 are sometimes referred to as juvenile-onset Parkinson's disease.\n\nOften the first symptom of Parkinson's disease is trembling or shaking (tremor) of a limb, especially when the body is at rest. Typically, the tremor begins on one side of the body, usually in one hand. Tremors can also affect the arms, legs, feet, and face. Other characteristic symptoms of Parkinson's disease include rigidity or stiffness of the limbs and torso, slow movement (bradykinesia) or an inability to move (akinesia), and impaired balance and coordination (postural instability). These symptoms worsen slowly over time.\n\nParkinson's disease can also affect emotions and thinking ability (cognition). Some affected individuals develop psychiatric conditions such as depression and visual hallucinations. People with Parkinson's disease also have an increased risk of developing dementia, which is a decline in intellectual functions including judgment and memory.

Tyrosine hydroxylase (TH) deficiency is associated with a broad phenotypic spectrum. Based on severity of symptoms/signs as well as responsiveness to levodopa therapy, clinical phenotypes caused by pathogenic variants in TH are divided into (1) TH-deficient dopa-responsive dystonia (the mild form of TH deficiency), (2) TH-deficient infantile parkinsonism with motor delay (the severe form), and (3) TH-deficient progressive infantile encephalopathy (the very severe form). In individuals with TH-deficient dopa-responsive dystonia (DYT5b, DYT-TH), onset is between age 12 months and 12 years; initial symptoms are typically lower-limb dystonia and/or difficulty in walking. Diurnal fluctuation of symptoms (worsening of the symptoms toward the evening and their alleviation in the morning after sleep) may be present. In most individuals with TH-deficient infantile parkinsonism with motor delay, onset is between age three and 12 months. In contrast to TH-deficient DRD, motor milestones are overtly delayed in this severe form. Affected infants demonstrate truncal hypotonia and parkinsonian symptoms and signs (hypokinesia, rigidity of extremities, and/or tremor). In individuals with TH-deficient progressive infantile encephalopathy, onset is before age three to six months. Fetal distress is reported in most. Affected individuals have marked delay in motor development, truncal hypotonia, severe hypokinesia, limb hypertonia (rigidity and/or spasticity), hyperreflexia, oculogyric crises, ptosis, intellectual disability, and paroxysmal periods of lethargy (with increased sweating and drooling) alternating with irritability.

Parkinson's disease is a progressive disorder of the nervous system. The disorder affects several regions of the brain, especially an area called the substantia nigra that controls balance and movement.\n\nGenerally, Parkinson's disease that begins after age 50 is called late-onset disease. The condition is described as early-onset disease if signs and symptoms begin before age 50. Early-onset cases that begin before age 20 are sometimes referred to as juvenile-onset Parkinson's disease.\n\nOften the first symptom of Parkinson's disease is trembling or shaking (tremor) of a limb, especially when the body is at rest. Typically, the tremor begins on one side of the body, usually in one hand. Tremors can also affect the arms, legs, feet, and face. Other characteristic symptoms of Parkinson's disease include rigidity or stiffness of the limbs and torso, slow movement (bradykinesia) or an inability to move (akinesia), and impaired balance and coordination (postural instability). These symptoms worsen slowly over time.\n\nParkinson's disease can also affect emotions and thinking ability (cognition). Some affected individuals develop psychiatric conditions such as depression and visual hallucinations. People with Parkinson's disease also have an increased risk of developing dementia, which is a decline in intellectual functions including judgment and memory.

Parkinson's disease is a progressive disorder of the nervous system. The disorder affects several regions of the brain, especially an area called the substantia nigra that controls balance and movement.\n\nGenerally, Parkinson's disease that begins after age 50 is called late-onset disease. The condition is described as early-onset disease if signs and symptoms begin before age 50. Early-onset cases that begin before age 20 are sometimes referred to as juvenile-onset Parkinson's disease.\n\nOften the first symptom of Parkinson's disease is trembling or shaking (tremor) of a limb, especially when the body is at rest. Typically, the tremor begins on one side of the body, usually in one hand. Tremors can also affect the arms, legs, feet, and face. Other characteristic symptoms of Parkinson's disease include rigidity or stiffness of the limbs and torso, slow movement (bradykinesia) or an inability to move (akinesia), and impaired balance and coordination (postural instability). These symptoms worsen slowly over time.\n\nParkinson's disease can also affect emotions and thinking ability (cognition). Some affected individuals develop psychiatric conditions such as depression and visual hallucinations. People with Parkinson's disease also have an increased risk of developing dementia, which is a decline in intellectual functions including judgment and memory.

Parkinson disease-23 (PARK23) is a progressive neurodegenerative disorder characterized by young-adult onset of parkinsonism associated with progressive cognitive impairment leading to dementia and dysautonomia. Some individuals have additional motor abnormalities. Affected individuals become severely disabled within a few decades (summary by Lesage et al., 2016).

Any Parkinson disease in which the cause of the disease is a mutation in the CHCHD2 gene.

Parkinsonism with polyneuropathy (PKNPY) is an autosomal dominant disorder characterized by asymmetrical tremor-dependent parkinsonism. The age of onset ranges from the late forties to mid-sixties, and patients have a good response to levodopa (summary by Lin et al., 2020).

Parkinson disease-24 (PARK24) is an autosomal dominant disorder characterized by classic Parkinson disease features, including adult onset, asymmetric limb involvement initially, and slowly progressive motor dysfunction. PARK24 shows incomplete penetrance, consistent with the presence of the PSAP mutation being a susceptibility factor for development of the disease (Oji et al., 2020). For a phenotypic description and a discussion of genetic heterogeneity of Parkinson disease, see 168600.

Parkinson disease-25 (PARK25) is a progressive neurodegenerative disorder characterized by onset of parkinsonism in late childhood/adolescence and developmental delay/impaired intellectual development. Cognitive impairment is mild to moderate and nonprogressive (Fevga et al., 2023). For a general phenotypic description and a discussion of genetic heterogeneity of Parkinson disease, see 168600.