Kisho is an information platform, not a medical provider. Nothing on this site constitutes medical advice, diagnosis, or treatment recommendations. All content is aggregated from publicly available sources (including ClinicalTrials.gov, PubMed, FDA.gov, and Orphanet) and is provided for informational purposes only. Clinical trial eligibility, treatment decisions, and any health-related actions should always be discussed with a qualified healthcare professional. Kisho does not endorse any specific therapy, organization, or clinical trial. Terms of use · Privacy policy
A rare paroxysmal movement disorder characterized by episodes of sustained, conjugate, upward deviation of the eyes and down beating saccades in attempted downgaze (with preserved horizontal eye movements) which is accompanied by ataxic symptomatology (unsteady gait, lack of balance and movement coordination disturbances) in an otherwise healthy individual. Bilateral vertical nystagmus is associated. Symptoms generally disappear spontaneously within 1-2 years after onset.
No HPO annotations are available for this condition.
Clinical information on spinocerebellar ataxia type 20 (SCA20) is based on the index pedigree, an Australian family of Anglo-Celtic descent that is the only family with SCA20 reported to date . The 16 affected family members had onset between age 19 and 64 years (mean 47). SCA20 presents with dysarthria without ataxia in a majority (10/16); the dysarthria may be of abrupt (2/16) or subacute (1/16) onset. It often combines the clinical appearance of spasmodic adductor dysphonia with cerebellar dysarthria. Other initial symptoms were dysarthria with simultaneous gait ataxia (2/16), gait ataxia alone (2/16), upper-limb kinetic and isometric tremor (1/16), and episodic vertigo (1/16).
Source: GeneReviews — "Spinocerebellar Ataxia Type 20"
DAGLA encodes diacylglycerol lipase alpha (1,042 aa). Serine hydrolase that hydrolyzes arachidonic acid-esterified diacylglycerols (DAGs) to produce the principal endocannabinoid, 2-arachidonoylglycerol (2-AG). Highest expression in Brain Cortex (26.9 TPM) and Brain Cerebellum (23.4 TPM).
Benign paroxysmal tonic upgaze of childhood with ataxia is associated with mutations in the DAGLA gene on chromosome 11.
DAGLA is classified as a druggable target (Druggable Genome and Enzyme categories) with score 1.3.
The penetrance is unknown, as the involved gene has not been identified.
Source: GeneReviews — "Spinocerebellar Ataxia Type 20"
Spinocerebellar ataxia type 20 (SCA20) should be considered in individuals with a slowly progressive ataxia without sensory features who have the following findings:
Onset with dysarthria (rather than with gait ataxia) that may be abrupt in onset (seen in ~66%)
Palatal tremor (in ~66%)
Family history consistent with autosomal dominant inheritance
Additional findings may include the following:
Hypermetric horizontal saccades (without nystagmus or disturbance of vestibuloocular reflex gain) in about half
Mild hyperreflexia (typically without spasticity or extensor plantar responses) in a minority
Postural tremor of arms with or without involvement of the head (seen in a minority; may be the first symptom)
Neuroimaging
Source: GeneReviews — "Spinocerebellar Ataxia Type 20"
The differential diagnosis of spinocerebellar ataxia type 20 (SCA20) is essentially that of its component features, as the constellation of progressive, dominantly inherited ataxia, early dentate calcification, and (often) palatal tremor is distinctive. Inherited ataxia. See Hereditary Ataxia Overview. Dentate calcification appears early in SCA20; it was seen in five affected individuals who had been symptomatic for five years or less.
Source: GeneReviews — "Spinocerebellar Ataxia Type 20"
Genetic testing for DAGLA is available. Testing is considered confirmatory for diagnosis.
No approved treatments are currently available for benign paroxysmal tonic upgaze of childhood with ataxia. The disease remains an area of unmet medical need.
To establish the extent of disease in an individual diagnosed with spinocerebellar ataxia type 20 (SCA20), the evaluations summarized in this section (if not performed as part of the evaluation that led to the diagnosis) are recommended:
Careful clinical and neurologic evaluation
Speech assessment
Consultation with a clinical geneticist and/or genetic counselor
Affected persons should be followed by a neurologist with consultation from physiatrists and physical and occupational therapists. Although neither exercise nor physical therapy has been shown to stem the progression of incoordination or muscle weakness, individuals should maintain activity. Canes and walkers help prevent falls. Modification of the home with such conveniences as grab bars, raised toilet seats, and ramps to accommodate motorized chairs may be necessary. Speech therapy and communication devices such as writing pads and computer-based devices may benefit those with dysarthria or dysphonia. Weighted eating utensils and dressing hooks help maintain a sense of independence. Weight control is important because obesity can exacerbate difficulties with ambulation and mobility. When dysphagia becomes troublesome, videofluoroscopic swallow evaluation can identify the consistency of food least likely to trigger aspiration.
Secondary complications are unlikely in the early years of the disease. Later, prevention of f...
Source: GeneReviews — "Spinocerebellar Ataxia Type 20"
Affected individuals should avoid alcohol as well as medications known to cause nerve damage (e.g., isoniazid).
Source: GeneReviews — "Spinocerebellar Ataxia Type 20"
Search ClinicalTrials.gov in the US and EU Clinical Trials Register in Europe for access to information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder.
Source: GeneReviews — "Spinocerebellar Ataxia Type 20"
1 trial found
The following are appropriate:
Periodic speech assessment if dysphagia becomes a problem
Routine follow up with a neurologist about every two years or as needed
Source: GeneReviews — "Spinocerebellar Ataxia Type 20"
Estimated prevalence: <1 in 1,000,000 (VERY_RARE).
1 clinical trial registered, 1 recruiting. Interventions under study include other interventions. Research is primarily sponsored by academic and government institutions.
Data assembled from 6 of 12 sources · Last updated Sep 20, 2026, 7:28 PM UTC
Online Mendelian Inheritance in Man
European rare disease database
Genetic and Rare Diseases Info Center