Clinical Guidance

No clinically relevant genotype-phenotype correlations have been identified.

Source: GeneReviews — "Hypermanganesemia with Dystonia 1"

Diagnostic Criteria

Hypermanganesemia with dystonia 1 (HMNDYT1) presents as a movement disorder associated with manganese accumulation in the basal ganglia. No consensus clinical diagnostic criteria have been published.

Suggestive Findings

HMNDYT1 should be suspected in individuals with typical clinical, brain MRI, and laboratory findings and family history.

Clinical Findings

An early- and a late-onset form exist:

• Childhood-onset form (between ages 2 and 15 years). Usually four-limb dystonia, leading to a characteristic high-stepping gait ("cock-walk gait"), dysarthria, fine tremor, and bradykinesia or on occasion spastic paraplegia

• Adult-onset form. Parkinsonism (shuffling gait, rigidity, bradykinesia, hypomimia, and monotone speech) unresponsive to L-dopa treatment

Brain MRI

T1-weighted images show characteristic ...

Source: GeneReviews — "Hypermanganesemia with Dystonia 1"

Differential Diagnosis

Acquired hypermanganesemia. Overexposure to manganese is known to be neurotoxic and causes "manganism" – a distinct syndrome of extrapyramidal movement disorder (dystonia/parkinsonism) combined with high signal intensity of the basal ganglia on T1-weighted MR images of the brain resulting from manganese accumulation in the basal ganglia .

Source: GeneReviews — "Hypermanganesemia with Dystonia 1"

Management Guidelines

No clinical practice guidelines for hypermanganesemia with dystonia 1 (HMNDYT1) have been published. Evaluations Following Initial Diagnosis To establish the extent of disease and needs of an individual diagnosed with HMNDYT1, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended. Table 4. Recommended Evaluations Following Initial Diagnosis in Individuals with Hypermanganesemia with Dystonia 1

Source: GeneReviews — "Hypermanganesemia with Dystonia 1"

Clinical Guidance

Foods very high in manganese (cloves; saffron; nuts; mussels; dark chocolate; pumpkin, sesame, and sunflower seeds) should be avoided.

Source: GeneReviews — "Hypermanganesemia with Dystonia 1"

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 — "Hypermanganesemia with Dystonia 1"

Surveillance Guidelines

Table 6.

Recommended Surveillance for Individuals with Hypermanganesemia with Dystonia 1

System/Concern | Evaluation | Frequency

Hypermanganesemia chronic liver disease

| Liver function tests; hemoglobin; iron indices; whole-blood manganese (if available) | Every 3 mos

Follow up w/neurologist hepatologist (w/repeat assessment of brain MRI liver ultrasound biopsy) | When clinically indicated by worsening liver function /or for monitoring treatment at least every 6-12 mos

Source: GeneReviews — "Hypermanganesemia with Dystonia 1"