Progressive Myoclonic Encephalopathies Flashcards

1
Q

Unverricht disease (Unverricht–Lundborg disease, progressive myoclonic epilepsy 1 (EPM1), Baltic myoclonus, Mediterranean myoclonus)

Semiology

A

Characterized by:

  • cortical myoclonus
  • generalised tonic–clonic seizures (GTCSs)
  • mild progressive ataxia.

Patients are initially neurologically normal. Mild cognitive deterioration also occurs with time.

A characteristic feature of UL is the relative remission over days.

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2
Q

Unverricht disease (Unverricht–Lundborg disease, progressive myoclonic epilepsy 1 (EPM1), Baltic myoclonus, Mediterranean myoclonus)

Etiology

A

Autosomal recessive disorder caused by mutations of the CTSB gene (21q22.3), which encodes Cystatin B an inhibitor of lysosomal cysteine proteases.

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3
Q

Lafora disease (Lafora body disease, PME with polyglucosan bodies)

Semiology

A

Mainly myoclonia and occipital seizures (spontaneous or photic induced), and sometimes GTCS.

Behavioral and cognitive decline may be the initial manifestations

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4
Q

Lafora disease (Lafora body disease, PME with polyglucosan bodies)

Etiology

A

Autosomal recessive.

Genes: EPM2A (6q24) - protein Laforin

EPM2B (6p22) - protein Malin (milder course)

Lafora bodies are PAS positive diastase resistant polyglucosan inclusions.

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5
Q

Ceroid Lipofuscinoses

Semiology

A

Rapid and progressive neurocognitive deterioration.

Visual loss due to retinal atrophy is a prominent feature of all but the adult form.

Myoclonia and multiple seizure types occur.

Ataxia, dementia and behavioral problems.

Progressive deterioration of background (“vanishing EEG activity” in infantile NCL).

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6
Q

Ceroid Lipofuscinoses

Etiology

A

Mainly autosomal recessive. Seven NCL gene loci have been identified:

CLN1 - PPT1 (1p32) - Palmythoil protein thioesterase.

CLN2 - TPP1 (11p15) - Trypeptidyl peptidase I

CLN3 - CLN3 (16p12) - protein CLN3

CLN4- Unknown

CLN5 - CLN5 (13q21) - protein CLN5

CLN6 - CLN6 (15q21) - protein CLN6

CLN8 - CLN8 (8p22) - protein CLN8

CLN10 - CTSD (11p15) - Cathepsin D.

In general, the disease is characterized by the intracellular accumulation of lipopigments.

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7
Q

Sialidosis (type I and II)

Semiology

A

Visual impairment, myoclonus and other seizure types, ataxia. Cherry red spots in the retina.

Types I and II have the same clinical manifestations, but type II is more severe

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8
Q

Sialidosis (type I and II)

Etiology

A

Result from the inherited deficiency of the lysosomal enzyme alpha-N-acetylneuraminidase due to mutations in the gene NEU1 (6p21), which codes for the protein Neuraminidase.

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9
Q

Myoclonic epilepsy associated with ragged red fibers (MERRF)

Semiology

A
MERRF is characterized by:
1- Cortical Myoclonus

2- Ataxia
3- Mild atrophy
4- Cognitive Impairment

Both genders equally affected.

Progressive ataxia is the main cause of disability. Myopathy is mild, but exercise intolerance is prominent.

Lactic acidosis, peripheral neuropathy and short stature are common. Strokes may occur (as in MELAS).

The phenotype depends on the mutation load.

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10
Q

Myoclonic epilepsy associated with ragged red fibers (MERRF)

Etiology

A

The gene is MT-TK, which codes for mitochondrial tRNA lysine.

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11
Q

Dentatorubral-pallidoluysian atrophy (DRPLA, Naito-Oyanagi syndrome)

Semiology

A

Cerebellar ataxia and dementia are the main features.


If onset before early adulthood, cortical myoclonus and other seizure types are observed. In older onsets, seizures may be milder or absent.

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12
Q

Dentatorubral-pallidoluysian atrophy (DRPLA, Naito-Oyanagi syndrome)

Etiology

A

DRPLA gene ATN1 codes for the protein Atrophin1.



The molecular defect is a trinucleotide expansion. Anticipation is also observed.

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13
Q

Angelman syndrome

Semiology

A

Defined by:

Severe developmental delay.

Severe speech impairment, gait ataxia



Myoclonic jerks



Other epileptic seizures

.

Happy demeanor with excessive chortling



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14
Q

Angelman syndrome

Etiology

A

Failure of expression of the maternal copy of the gene UBE3A (15q11-q13), which encodes Ubiquitin Ligase 3A.



Usually maternal de novo deletion (approximately 70% of cases).

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