Related Experiment Video
Updated: Aug 9, 2026
07:46
Gait Analysis of Age-dependent Motor Impairments in Mice with Neurodegeneration
Published on: June 18, 2018
Early-onset familial parkinsonism due to POLG mutations
Guido Davidzon1, Paul Greene, Michelangelo Mancuso
1Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA.
Annals of Neurology
|April 25, 2006
Summary
Mutations in the POLG gene cause early-onset parkinsonism and peripheral neuropathy. This finding expands the known genetic causes of these debilitating neurological conditions.
Area of Science:
- Genetics
- Neurology
- Mitochondrial Biology
Background:
- Early-onset parkinsonism and peripheral neuropathy present significant diagnostic challenges.
- Identifying the molecular underpinnings is crucial for understanding disease mechanisms and developing targeted therapies.
Observation:
- Two sisters presented with early-onset parkinsonism and sensorimotor axonal peripheral neuropathy.
- Clinical and electrophysiological findings were consistent with a combined neurological disorder.
Findings:
- Genetic analysis excluded mutations in parkin and PINK1.
- Muscle biopsies revealed mitochondrial abnormalities, including ragged-red fibers and reduced respiratory chain complex activities.
- Sequence analysis identified compound heterozygous pathogenic mutations in the POLG gene, encoding the mitochondrial DNA polymerase.
Implications:
- Mutations in POLG are a significant cause of early-onset parkinsonism and peripheral neuropathy.
- This expands the phenotypic spectrum of POLG-related disorders, highlighting its role beyond progressive external ophthalmoplegia.
- Understanding the role of POLG in mitochondrial DNA maintenance offers new avenues for therapeutic intervention in neurodegenerative diseases.
Related Concept Videos
01:24Parkinson Disease l: Introduction
Parkinson’s disease is a chronic, progressive neurodegenerative disorder that primarily affects movement. It is characterized by motor symptoms such as resting tremors, muscle rigidity, bradykinesia (slowness of movement), and postural instability. Patients may notice hand tremors at rest, stiffness during movement, or a shuffling gait. In addition to motor features, non-motor symptoms include sleep disturbances, mood and behavioral changes, constipation, and cognitive impairment, all of which...
01:24Parkinson Disease ll: Pathophysiology
Parkinson disease (PD) is a progressive neurodegenerative disorder primarily affecting movement, with additional non-motor features. Its pathophysiology involves complex interactions among genetic susceptibility, environmental exposures, and cellular dysfunction, including dopaminergic neuron loss, protein aggregation, and mitochondrial impairment.Selective NeurodegenerationA key feature is the degeneration of dopaminergic neurons in the substantia nigra pars compacta, leading to reduced...
01:15Parkinson's Disease: Overview
Neurodegenerative disorders are progressive diseases that cause irreversible damage and loss to neurons in specific brain areas. Examples of these disorders include Parkinson's disease, Alzheimer's disease, Multiple Sclerosis (MS), and Amyotrophic Lateral Sclerosis (ALS). These disorders share characteristics such as proteinopathies, selective neuronal vulnerability, and a complex interplay between genetic and environmental factors. The primary therapeutic goal for these conditions is to...
01:24Parkinson's Disease: Treatment
Neurodegenerative disorders, such as Parkinson's Disease (PD), involve the gradual and irreversible destruction of neurons in particular brain areas. These disorders exhibit standard features like proteinopathies, selective vulnerability of some neurons, and an interaction of intrinsic properties, genetics, and environmental influences in neural injury.
Parkinson's Disease is primarily a result of the loss of dopaminergic neurons in the substantia nigra pars compacta. The cornerstone of its...
Parkinson's Disease is primarily a result of the loss of dopaminergic neurons in the substantia nigra pars compacta. The cornerstone of its...
01:11Alterations in Muscle Tone lll
Rigidity and myotonia are distinct abnormalities of muscle tone that affect resistance and relaxation during movement. Although both involve altered muscle contraction, they arise from different neurological and muscular mechanisms.CharacteristicsRigidity is characterized by uniform resistance to passive movement across the entire range, independent of speed, affecting flexors and extensors equally. It may appear as lead-pipe rigidity (smooth, constant resistance) or cogwheel rigidity...
01:21Huntington Disease l: Introduction
Huntington disease or HD is a progressive, fatal neurodegenerative disorder inherited in an autosomal dominant pattern.PathophysiologyIt is caused by expansion of the CAG trinucleotide repeat in the HTT gene on chromosome 4 (4p16.3), producing an abnormal huntingtin protein with an expanded polyglutamine tract. This misfolded protein disrupts cellular function, leading to neuronal death. Normal alleles have ≤26 repeats, 27–35 are intermediate (risk of expansion), 36–39 show reduced penetrance,...