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deafness dystonia syndrome - Clinical Profile, Genes & Research | Kisho | Kisho

Features include always present findings: Mild intellectual disability, Dystonia, Postlingual sensorineural hearing impairment, and Intrinsic hand muscle atrophy and others; and common findings: Abnormal cochlea morphology, Prelingual sensorineural hearing impairment, Inner ear hearing loss (sensorineural hearing impairment), and Damage to the optic nerve (optic atrophy) and others. 53 total HPO annotations.

Organ System	Phenotype Count	Example Features
Brain and nerves	24	Difficulty swallowing (dysphagia), Mild intellectual disability, Dystonia
Ears	6	Progressive sensorineural hearing impairment, Postlingual sensorineural hearing impairment, Abnormal cochlea morphology
Muscles	5	Intrinsic hand muscle atrophy, Damage to the optic nerve (optic atrophy), Global brain atrophy
Eyes	4	Cerebral visual impairment, Visual impairment, Damage to the optic nerve (optic atrophy)
Bones and joints	3	Increased susceptibility to fractures, Abnormal posturing, Postural instability
Digestive system	1	Difficulty swallowing (dysphagia)
Arms and legs	1	Intrinsic hand muscle atrophy
Lungs and breathing	1	Aspiration pneumonia

GeneReviews

Clinical Guidance

Deafness-dystonia-optic neuronopathy (DDON) syndrome is a progressive disorder with prelingual or postlingual sensorineural hearing impairment in early childhood. The hearing impairment is always the presenting manifestation. Typically, DDON is associated with slowly progressive dystonia or ataxia in the teens, slowly progressive decreased visual acuity from approximately age 20 years, and dementia from approximately age 40 years. Psychiatric manifestations such as personality change and paranoia may appear in childhood and progress. The deafness and pronounced visual impairment severely compromise communication in late adulthood.

Source: GeneReviews — "Deafness-Dystonia-Optic Neuronopathy Syndrome"

Diagnosis

Drawn from GeneReviews diagnostic guidelines, newborn screening panel status (RUSP), and ClinGen gene-disease validity classifications. Reflects current clinical evidence and consensus where available.

GeneReviews

Diagnostic Criteria

Formal diagnostic criteria for deafness-dystonia-optic neuronopathy (DDON) syndrome have not been established. Scope of this chapter. Deafness-dystonia-optic neuronopathy (DDON) syndrome occurs as either a single-gene disorder resulting from a pathogenic variant in TIMM8A or a contiguous gene deletion at Xq22.1 that includes BTK and additionally causes X-linked agammaglobulinemia (XLA). XLA will not be discussed further in this chapter.

Suggestive Findings

Deafness-dystonia-optic neuronopathy (DDON) syndrome is suspected in males with the following:

Source: GeneReviews — "Deafness-Dystonia-Optic Neuronopathy Syndrome"

GeneReviews

Differential Diagnosis

Specific disorders that share features with deafness-dystonia-optic neuronopathy (DDON) syndrome. See . Note: De novo pathogenic variants in TIMM8A in some families may mimic autosomal recessive inheritance and thus complicate the ability to distinguish between X-linked and autosomal causes of dystonia. Table 2. Other Genes of Interest in the Differential Diagnosis of DDON Syndrome

Gene(s)1	DifferentialDisorder	MOI	Features of Differential Disorder
MELAS	Mat	The combination of optic atrophy, hearing loss, neurologic signs suggests mt disorders such as MELAS.; See also Mitochondrial Disorders Overview.	Dystonia uncommon in MELAS; Short stature, generalized tonic-clonic seizures, recurrent headaches/vomiting, anorexia common in MELAS SERAC1

Genetic testing for TIMM8A is available. Testing is considered confirmatory for diagnosis.

Treatment

Compiled from FDA-approved drug records, orphan drug designations, and FDA Adverse Event Reporting System (FAERS) safety data. GeneReviews management guidance is included where available.

No approved treatments are currently available for deafness dystonia syndrome. The disease remains an area of unmet medical need.

GeneReviews

Management Guidelines

Evaluations Following Initial Diagnosis Affected males. To establish the extent of disease and needs in a male diagnosed with deafness-dystonia-optic neuronopathy (DDON) syndrome, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended. Table 3. Recommended Evaluations Following Initial Diagnosis in Males with DDON Syndrome

System/Concern	Evaluation	Comment
impairment	Formal audiologic assessment w/focus on possibility of auditory neuropathy	To determine extent of hearing impairment Speech-language assessment
Ataxia	Neurologic assessment	To provide baseline information Orthopedics/ physical medicine rehab/ PT OT eval
impairment	Ophthalmologic eval incl VEP	Incl visual acuity, color vision testing, visual field testing for evidence of central scotomas
Development	Developmental assessment; consider specialized testing for deaf /or visually impaired persons.	Incl motor, adaptive, cognitive evaluation for early intervention / special education Psychiatric/
Behavioral	Neuropsychiatric eval	For persons w/dementia /or psychiatric disturbance Miscellaneous/

Source: GeneReviews — "Deafness-Dystonia-Optic Neuronopathy Syndrome"

GeneReviews

Therapies Under Investigation

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 — "Deafness-Dystonia-Optic Neuronopathy Syndrome"

Clinical Trials

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Prognosis

Based on GeneReviews surveillance recommendations, HPO phenotype frequency and severity annotations, and published prevalence estimates from Orphanet and OMIM.

GeneReviews

Surveillance Guidelines

Table 5. Recommended Surveillance for Individuals with DDON Syndrome

System/Concern	Evaluation	Frequency
Hearing impairment	Audiologic eval	Annually Speech language development
Dystonia	Neurologic exam to monitor progression of dystonia review medications	Regular follow up depending on rate of progression PT/OT: review activities of daily living, gross motor fine motor needs Vision impairment
Behavioral	When clinically relevant	Individual follow up based on clinical findings Developmental progress educational needs; Effect of hearing impairment, vision impairment, mvmt disorder, changes in behavior /or cognitive abilities when clinically relevant; Be aware of signs of dementia in adults.
needs	Assess need for social work support (e.g., respite care, home nursing, other local resources) care coordination.	At each visit OT = occupational therapy; PT = physical therapy

Source: GeneReviews — "Deafness-Dystonia-Optic Neuronopathy Syndrome"

Phenotype severity distribution: 6 always present features, 15 common features.

Estimated prevalence: <1 in 1,000,000 (VERY_RARE).

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deafness dystonia syndrome

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deafness dystonia syndrome

Overview

Clinical Presentation

Clinical Guidance

Explore clinical features

Genetic Landscape

Clinical Guidance

Diagnosis

Diagnostic Criteria

Suggestive Findings

Differential Diagnosis

Treatment

Management Guidelines

Therapies Under Investigation

Clinical Trials

Prognosis

Surveillance Guidelines

Research Landscape

Recent Publications

Medical References

External Resources

OMIM

Orphanet

GARD

Related Diseases

Questions for Your Care Team

Questions for Your Care Team