ABGC Neuro Ataxias and Dementias 2026

Spinocerebellar Ataxia 1 (SCA1) - 3 Key Symptoms

Progressive Cerebellar Ataxia (Loss of coordination), Deterioration of Bulbar Function (Loss of speech/swallowing/eating/breathing), Ocular manifestations (hypermetric saccades (overshoot tracking), nystagmus (rapid eye movement))

Spinocerebellar Ataxia 2 (SCA2) - 3 Key Symptoms

SLOW. Progressive Cerebellar Ataxia (Loss of coordination), Parkinsonism (Bradykinesia (slow move), Rigidity, Rest Tremor, Standing Instability) w/ areflexia, Ocular manifestations (Slow saccades (slow tracking), nystagmus (rapid eye movement))

Spinocerebellar Ataxia 3 (SCA3; Machado-Joseph) - 3 Key Symptoms

Most Common SCA. Progressive Cerebellar Ataxia (Loss of coordination), Bulged Eyes, Parkinsonism (Bradykinesia (slow move), Rigidity, Rest Tremor, Standing Instability) w/ areflexia

Spinocerebellar Ataxia 6 (SCA6) - 3 Key Symptoms

Pure cerebellar ataxia (loss of coordination) w/ hyperreflexia, Downbeat Nystagmus (vertical: upward drift, downward corrective snap), Deterioration of Bulbar Function (Loss of speech/swallowing/eating/breathing)

Spinocerebellar Ataxia 7 (SCA7) - 3 Key Symptoms

Progressive Cerebellar Ataxia (Loss of coordination), Cone-Rod Retinal Dystrophy (blindness to blue/yellow and central vision), Deterioration of Bulbar Function (Loss of speech/swallowing/eating/breathing)

Friedreich Ataxia - 3 Key Symptoms

Lower -> Upper Progressive Ataxia, Hypertrophic Cardiomyopathy (big heart muscle), Peripheral Neuropathy (loss of position/vibration sense in lower limbs)

Huntington Disease - 3 Key Symptoms

Chorea (jerky movement), Cognitive Decline and Dementia (Exec. Dysf., Memory), Psychiatric Changes (Irritability/Aggression, Depression)

Alzheimer Disease - 3 Key Symptoms

Cognitive Decline and Dementia (Exec. Dysf., Short Term Memory early sign, Long Term Memory late sign), CNS Involvement +Seizures +Psychosis, Behavioral Changes (Withdrawal, Agitation, Incapacitation)

GRN Frontotemporal Dementia - 3 Key Symptoms

Cognitive Decline and Dementia (Exec. Dysf. esp., Memory), Primary Progressive Aphasia (Loss of word processing), Parkinsonism (Bradykinesia (slow move), Rigidity, Rest Tremor, Standing Instability)

MAPT Frontotemporal Dementia - 3 Key Symptoms

Progressive Supranuclear Palsy/Vertical Gaze Palsy (difficulty looking vertically), Cognitive Decline and Dementia (Exec. Dysf. esp., Memory), Parkinsonism (Bradykinesia (slow move), Rigidity, Rest Tremor (rare), Standing Instability)

Amyotrophic Lateral Sclerosis (ALS) - 3 Key Symptoms

2 Main Classifications : Limb-Onset: Begins w/ peripheral muscle weakness + rigidity; Bulbar-Onset: Begins w/ Deterioration of Bulbar Function (Loss of speech/swallowing/eating/breathing); Death common by respiratory failure. CLASSICAL NEEDS UPPER AND LOWER MOTOR NEURON DEGENERATION SIGNS: Upper: Spasticity (muscle rigidity), hyperreflexia, slow move; Lower: muscle weakness, atrophy, fasciculations

Ataxias - 3 Key Features

Trinucleotide Repeat Expansion, Progressive Cerebellar Atrophy (loss of coordination), Ocular + Bulbar Involvement

Dementias - 3 Key Features

Cognitive Decline (Exec. Dysf., Memory), High Risk Alleles + Multifactorial Inheritance, Behavioral Changes

Spinocerebellar Ataxia 1 (SCA1) - Brain Imaging

MRI: Cerebellar and Brain Stem Atrophy

Spinocerebellar Ataxia 1 (SCA1) - Gene and Inheritance

AD (Paternal-Transmission Anticipation more likely); ATXN1 repeat expansion; Full Penetrance: CAG trinucleotide repeats of 39-44 w/out CAT interruption, 46-70 CAG repeats uninterrupted w/ CAT interruption

Spinocerebellar Ataxia 1 (SCA1) - Onset and Progression

30-40y; the more uninterrupted repeats, the younger the onset; Fastest progression of the SCA's 10-30y. Juvenile onset observed.

Spinocerebellar Ataxia 1 (SCA1) - Treatment

PT, OT, ST, NeuroPsych, Pain Management, Communication Devices, Easy-Swallow Foods

Spinocerebellar Ataxia 2 (SCA2) - Brain Imaging

MRI: Cerebellar and Brain Stem Atrophy

Spinocerebellar Ataxia 2 (SCA2) - Gene and Inheritance

AD (Paternal-Transmission Anticipation more likely) AND AR 31/31 CAG repeat homozygotes; ATXN2 repeat expansion; Full Penetrance: CAG trinucleotide repeats of 33+ (NOTE: 30-32 repeats = risk for ALS)

Spinocerebellar Ataxia 2 (SCA2) - Onset and Progression

40y; the more uninterrupted repeats, the younger the onset; Progression of 10-15y. Juvenile onset observed.

Spinocerebellar Ataxia 2 (SCA2) - Treatment

Walkers/Canes/Ramps/Wheelchair, Communication Devices, Easy-Swallow Foods, DOPA-responsive Parkinsonism, not responsive to PT, OT, ST.

Spinocerebellar Ataxia 3 (SCA3; Machado-Joseph) - Brain Imaging

MRI: Cerebellar and Brain Stem Atrophy + Basal Ganglia and Cerebral Cortex Atrophy

Spinocerebellar Ataxia 3 (SCA3; Machado-Joseph) - Gene and Inheritance

AD (Paternal-Transmission Anticipation more likely); ATXN3 repeat expansion; Full Penetrance: CAG trinucleotide repeats of 60-87

Spinocerebellar Ataxia 3 (SCA3; Machado-Joseph) - Onset and Progression

20-50y; the more uninterrupted repeats, the younger the onset; Progression of 10-20y. Juvenile onset observed.

Spinocerebellar Ataxia 3 (SCA3; Machado-Joseph) - Treatment

PT, OT, ST, NeuroPsych, Pain Management, Communication Devices, Easy-Swallow Foods, Walkers/Canes/Ramps/Wheelchair, DOPA-responsive Parkinsonism

Spinocerebellar Ataxia 6 (SCA6) - Brain Imaging

MRI: Cerebellar Atrophy

Spinocerebellar Ataxia 6 (SCA6) - Gene and Inheritance

AD w/out anticipation; CACNA1A repeat expansion; Full Penetrance: CAG trinucleotide repeats of 20-33

Spinocerebellar Ataxia 6 (SCA6) - Onset and Progression

20-70y; the more uninterrupted repeats, the younger the onset, Slowest progression of the SCA's w/ sex bias (faster in females) with normal lifespan. Juvenile onset observed.

Spinocerebellar Ataxia 6 (SCA6) - Treatment

Acetazolamide for ataxia; PT, OT, ST, NeuroPsych, Pain Management, Communication Devices, Easy-Swallow Foods, Walkers/Canes/Ramps/Wheelchair

Spinocerebellar Ataxia 7 (SCA7) - Brain Imaging

MRI: Cerebellar and Brain Stem Atrophy (Pons esp.)

Spinocerebellar Ataxia 7 (SCA7) - Gene and Inheritance

AD (Paternal-Transmission Anticipation more likely; MOST DRAMATIC ANTICIPATION OF SCA'S); ATXN7 repeat expansion; Full Penetrance: CAG trinucleotide repeats of 37-460

Spinocerebellar Ataxia 7 (SCA7) - Onset and Progression

Widest range of onset of SCA's, Juvenile onset is common; the more uninterrupted repeats, the younger the onset, the faster the progression (months in infants, decades in adults). >50y onset do not always progress to vision loss.

Spinocerebellar Ataxia 7 (SCA7) - Treatment

PT, OT, ST, NeuroPsych, Pain Management, Communication Devices, Easy-Swallow Foods, Walkers/Canes/Ramps/Wheelchair, Low vision aids

Friedreich Ataxia - Brain Imaging

MRI: Cerebellar and Brain Stem Atrophy + Thinning of Spinal Cord

Friedreich Ataxia - Gene and Inheritance

AR; Compound Het FXN repeat expansion (96%) OR 1 FXN repeat expansion + 1 FXN Large Del/small del/dup Path Var (4%); Full Penetrance: GAA trinucleotide repeats of 66-1,300. G or A interruptions lead to later onset.

Friedreich Ataxia - Onset and Progression

10-15y; GAA1 (the shorter expansion of the two compound het alleles) the longer, the earlier the onset, the faster the progression; GAA2 (the larger expansion of the two compound het alleles) no length impact on onset or progression. Progression of 20-45 years. G or A interruptions lead to later onset.

Friedreich Ataxia - Treatment

Omaveloxone slows progression; PT, OT, ST, NeuroPsych, Communication Devices, Easy-Swallow Foods, Walkers/Canes/Ramps/Wheelchair, EKG monitoring, Surgery

Huntington Disease - Brain Imaging

MRI: Bilateral atrophy of Putamen and Caudate Nucleus

Huntington Disease - Gene and Inheritance

AD; HTT Repeat Expansion (Paternal-Transmission Anticipation more likely); Full Penetrance: CAG (cranky angry grandpa) trinucleotide repeats of 40+

Huntington Disease - Onset and Progression

40-50y; the more uninterrupted repeats, the younger the onset, the faster the progression. Progression of 15-20y

Huntington Disease - Treatment

Pharmacologic therapies for chorea, rigidity, and psychiatric symptoms. PT, OT, ST, NeuroPsych. NOT DOPA-RESPONSIVE = increased chorea

Alzheimer Disease - Brain Imaging

MRI: Hippocampus Atrophy, Global Shrinkage, Large Ventricles; PET: Molecular findings of Beta-Amyloid Plaques in Cerebral Cortex, Abn. Tau Tangles, and low glucose metabolism in relevant regions

Alzheimer Disease - Gene and Inheritance

Late-Onset multifactorial, Early-Onset AD risk factor, Down Syndrome de Novo 90% penetrance; Early-Onset genes in order of proportion: PSEN1, APP, PSEN2 (NOT APOE, negligibly actionable increase to risk)

Alzheimer Disease - Onset and Progression

Late Onset: >60-65y, Early Onset:

Alzheimer Disease - Treatment

Cholinesterase inhibitors, Lecanemab (anti-amyloid antibody) slows progression (need APOE status to know risk for brain bleed), PT, OT, ST, Neuropsych.

GRN Frontotemporal Dementia - Brain Imaging

MRI: often asymmetric atrophy in frontal, temporal, and parietal lobes; PET: low glucose metabolism in frontal and temporal lobes and rules out Alzheimer with lack of beta-amyloid accumulation

MAPT Frontotemporal Dementia - Brain Imaging

MRI: often symmetric atrophy in frontal or frontal and temporal lobes; PET: rules out Alzheimer with lack of beta-amyloid accumulation

GRN Frontotemporal Dementia - Gene and Inheritance

AD; GRN

GRN Frontotemporal Dementia - Onset and Progression

35-85y, Mean = 65y ; 3-12y progression

GRN Frontotemporal Dementia - Treatment

Management of Neuropsychiatric manifestations with medication and Psychotherapy, Cholinesterase inhibitors also helpful

MAPT Frontotemporal Dementia - Gene and Inheritance

AD; MAPT

MAPT Frontotemporal Dementia - Onset and Progression

25-95y, Mean = 50y ; 10y progression

MAPT Frontotemporal Dementia - Treatment

PT, OT, ST, NeuroPsych. No other treatments available.

Amyotrophic Lateral Sclerosis (ALS) - Brain Imaging

Needle EMG: Needle Detects Fasciculations, EMG detects upper and lower neuron damage; MRI: hyperintensity/high signal in corticospinal tract

Amyotrophic Lateral Sclerosis (ALS) - Gene and Inheritance

AD genes: C9orf72 repeat expansion (most common), SOD1, FUS, TARDBP. AR gene: SOD1. C9orf72 hexanucleotide GGGGCC repeat expansion of >60 (+FTD, often Psych symptoms); SOD1 (-FTD); FUS (+FTD, often Bulbar Onset); TARDBP (+FTD). Many more less common genes.

Amyotrophic Lateral Sclerosis (ALS) - Onset and Progression

C9orf72: Mean = 58y (larger repeats = earlier onset); SOD1: Mean = 45y; FUS: Mean = 40y; TARDBP: Mean = 53y. 2-5y Progression

Amyotrophic Lateral Sclerosis (ALS) - Treatment

Palliative care; several medications approved to marginally slow progression, including one specific to SOD1 ALS. PT, OT, ST, NeuroPsych.