Clinical observation of a rare form of hereditary myoclonus epilepsy

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Introduction. Lafora disease is a rare, autosomal recessive hereditary disease from the group of progressive forms of epilepsy with myoclonus, characterized by partial and generalized epileptic seizures, extrapyramidal disorders, cognitive disorders and dementia [1]. The disease is caused by a gene mutation in chromosome 6, most often affecting the EPM2A gene, responsible for the synthesis of the laforin protein, in other cases EPM2B (NHLRC1), encoding the malin protein. Both of these proteins control glycogen metabolism [1, 2]. Thus, when glycogen metabolism is disrupted, amyloid cytoplasmic inclusions - Lafora bodies - are deposited in various organs and tissues of the body. Manifestation occurs at the age of 8-18 years from the onset of a generalized epileptic seizure. Subsequently, myoclonus, changes in the mental sphere and a decrease in cognitive functions with progressive dementia occur. There is no cure. As a rule, the disease progresses rapidly, leading to death after 4-10 years, due to the addition of intercurrent infections [3].
Target. Using a clinical case as an example, highlight a rare form of hereditary myoclonus epilepsy.
Clinical case. Patient E. Born from a second term labor, with the umbilical cord entwined twice around the fetal neck. Weight at birth: 3500 g, height: 52 cm. Consanguineous marriage. The medical history is complicated: the younger brother, cousin and maternal aunt have epilepsy. He was observed by a neurologist until 1 year of age for hypoxic-ischemic encephalopathy. He grew and developed, according to his mother, according to his age. The onset of seizures at the age of 8 years was generalized tonic-clonic convulsions; valproic acid was started. He was repeatedly treated in the psychoneurological department with a diagnosis of idiopathic generalized epilepsy in the form of tonic-clonic seizures. F06.827 + F83.0. VEM - generalized epileptiform paroxysmal activity. The following drugs were introduced into the treatment regimen: lacosamide, lamotrigine, topiramate, a course of corticosteroids - without effect. The ophthalmologist also diagnosed divergent monolateral strabismus OS. High degree of farsightedness OU.
At the age of 16, he received genetic counseling. Based on the results of a molecular genetic study, a homozygous mutation in the NHLRC1 gene was identified.
The diagnosis is Lafora's progressive myoclonic epilepsy (homozygous mutation in the NHLRC1 gene).
The last time I was admitted to the neurosurgical department of the CSCH named after. Silishcheva with a parental complaint of attacks with short-term freezing, fluttering of the eyelids, trembling in the limbs, falling of an object from the hands, adversion, head and eyes to the side, then falling, tension of the limbs, clonic convulsions. Also for loss of motor and cognitive skills, speech impairment, attacks of aggression and agitation.
Current therapy: valproic acid extended form 21 mg/kg/day, levetiracetam 42 mg/kg, perampanel 8 mg. While taking perampanel, there were no attacks for two weeks.
When examined by a neurologist: he understands spoken speech at the everyday level, and follows instructions selectively. Attention is reduced, disinhibited. Dysarthria. Tremor of the limbs and myoclonus, predominantly of the upper shoulder girdle, are periodically observed. The movement of the eyeballs is limited outward, convergence is weakened. Hypersalivation. Muscle tone is changed according to the spastic type. Tendon reflexes from the upper extremities and Achilles reflexes are animated. He doesn’t stand, he doesn’t walk. Does not perform the Romberg pose or coordination tests.
EEG results: against the background of pronounced diffuse changes in the bioelectrical activity of the brain, generalized epileptiform activity is recorded in the form of OMV complexes.
Brain MRI results: cortical atrophy, ventriculomegaly.
Treatment was carried out: valproic acid 1000 mg/day, levetiracetam 2000 mg/day, perampanel 8 mg/day, sibazon 2.0 IV No. 2.
While in the department, during treatment, the patient had serial myoclonic attacks every day. The patient was discharged for further outpatient treatment.
The patient has now been transferred to the adult service and his condition is progressively deteriorating.
Conclusion. Lafora's disease is a rare, but rapidly progressive form of myoclonic epilepsy that is not treatable and quickly leads to mortality, so the neurologist must be vigilant when encountering patients with progressive juvenile myoclonus epilepsy, drug resistance and extrapyramidal and cognitive impairment.

About the authors

Valeria Valerianovna Konopleva

Email: l.konopleva.01@mail.ru
ORCID iD: 0000-0002-5059-6274
SPIN-code: 2961-6595
Russian Federation, 414000, Russia, Astrakhan, st. Baku, 121

Zhuzhuna Tsotsonava

Author for correspondence.
Email: tsotsonava02@yandex.ru
Russian Federation, 414000, Russia, Astrakhan, st. Baku, 121

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