From the Research
Globular glial tauopathy (GGT) is a rare neurodegenerative disorder characterized by abnormal accumulation of tau protein in glial cells of the brain, particularly in astrocytes and oligodendrocytes, with the most recent study suggesting that female sex, lower motor neuron involvement, and asymmetric brain atrophy with preserved midbrain might be suggestive of underlying GGT 1.
Key Features of GGT
- The condition belongs to the family of frontotemporal lobar degeneration disorders and typically presents with a combination of motor dysfunction, cognitive decline, and behavioral changes.
- Currently, there is no cure or disease-modifying treatment for GGT, with management focusing on symptomatic treatment, including physical therapy for motor symptoms, cognitive rehabilitation for cognitive deficits, and medications like SSRIs or cholinesterase inhibitors for behavioral and cognitive symptoms, respectively.
- Supportive care is essential, including caregiver education and multidisciplinary approaches involving neurologists, psychiatrists, and therapists.
- The disease is progressive, with survival typically ranging from 3-7 years after symptom onset, as reported in a study of 88 published GGT cases 2.
Diagnosis and Pathophysiology
- GGT is caused by abnormal phosphorylation and aggregation of tau protein, forming distinctive globular inclusions in glial cells, which disrupts normal brain function and leads to neurodegeneration.
- Diagnosis requires neuropathological examination, as clinical features often overlap with other neurodegenerative conditions, and a recent study suggests that targeting glial tau accumulation or sustaining their neuron-supportive function might require different therapeutic or neuroprotective strategies 2.
- A study published in 2023 found that GGT type II is a separate neuropathological entity, characterized by neuronal and glial tau inclusions, including globular astrocytic and oligodendroglial inclusions 3.
Clinical Presentation and Subtypes
- The most common predominant clinical features of GGT are primary progressive aphasia, behavioral-variant frontotemporal dementia, upper motor neuron signs, memory impairment, and Richardson syndrome, as reported in a review of published data 2.
- GGT is classified into three neuropathological subtypes: Types I, II, and III, with Type II characterized by pyramidal features reflecting predominant motor cortex and corticospinal tract degeneration 4, 5.
- A study published in 2021 found that GGT type II presents as motor impairment due to pyramidal involvement, whereas type III is a combination of the features of types I and II 5.