A RARE CASE OF PROGRESSIVE MYOCLONIC EPILEPSY DUE TO SSPE

SSPE is a chronic complication of measles with a delayed onset and nearly fatal outcome. This “slow virus infection” results from a persistent infection with an altered measles virus, that is harboured intracellularly in the CNS. Patients usually presents with cognitive decline and myoclonus but atypical presentations are also quite common. Our case is of a 9 year old male child , previously neurodevelopmentally normal, presented with 4 months history of frequent fall due to jerky movements of the left upper and lower limbs which progresses to involve left half of the body, reduced attention span, cognitive decline and loss of speech. During hospitalisation, despite treatment with antibiotics , steroids , and antiepileptics ,disease progressed with myoclonic jerks , altered sensorium and nally child became comatose. CSF study is normal but MRI and EEG shows abnormalities. Based on clinical features and history of exanthematous illness at 6 months of age, measles igG antibody titres in CSF were tested , which came to be highly elevated conrming SSPE.

Clinical features and genetics in non-5q spinal muscular atrophy caused by acid ceramidase deficiency

Spinal muscular atrophy (SMA) is a spectrum of genetically and clinically heterogeneous diseases leading to the progressive degeneration of peripheric motor neurons with subsequent muscle weakness and atrophy. More than 95% of the cases of SMA are represented by homozygous mutations of the SMN1 gene (5q-SMA). Because this disease represents the leading cause of death due to a genetic cause and due to the availability of genetic therapies which can now save the life of the patient and stop the progress of the disease, early diagnosis is crucial. This report presents the case of a 13-year-old patient admitted to our hospital in 2018 who presented a phenotype typical to 5q-SMA. Next-generation sequencing (NGS) and Sanger sequencing of the SMN1 gene were performed, and a negative result was obtained. Consequently, we continued testing using whole-exome sequencing and discovered three mutations in the ASAH1 gene (one pathogenic and two variants of uncertain significance). Pathogenic mutations in the ASAH1 gene are responsible for spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME) and Farber disease, which overlapped with our patient’s phenotype. Currently, there are 45 SMA cases caused by mutations in the ASAH1 gene reported worldwide; however, the present case is the first reported in Romania.

Progressive myoclonic epilepsy due to rare mitochondrial ND6 mutation, m.14487T>C

IntroductionMitochondrial diseases exhibit wide phenotypic heterogeneity, and can present as progressive myoclonic epilepsy.SummaryWe report a case of adult-onset drug-resistant epilepsy, cortical myoclonus and bilateral optic neuropathies due to m.14487T>C, a rare mitochondrial gene mutation identified on whole-genome sequencing. This mutation, which affects the NADH dehydrogenase 6 (ND6) subunit of the mitochondrial respiratory chain, is most commonly implicated in cases of infantile-onset Leigh syndrome, although a broader phenotypic spectrum including migraine with aura and progressive myoclonic epilepsy have been described. Serial MRI scans over a 2-year period demonstrated the interval development of bihemispheric stroke-like lesions. Giant somatosensory evoked potentials and short-duration myoclonic jerks with craniocaudal spread on surface electromyography were consistent with cortical myoclonus. Optical coherence tomography showed bilateral symmetric thinning of the nerve fibre layer in the papillomacular bundles.ConclusionWhole-genome sequencing can help to provide a definitive diagnosis for mitochondrial disease and should be considered in situations where clinical suspicion remains high despite normal genetic panels or muscle histopathology. Mitochondrial disease can present as adult-onset progressive myoclonic epilepsy, and bilateral optic neuropathies can be a striking feature of ND6 mitochondrial gene mutations. In our case, severe cortical myoclonus affecting speech and swallowing remained highly drug-resistant, however, symptomatic benefit was derived from targeted onabotulinum toxin A injections.

A de novo SEMA6B variant in a Chinese patient with progressive myoclonic epilepsy-11 and review of the literature

Progressive myoclonic epilepsy is a group of neurodegenerative diseases with complex clinical and genetic heterogeneity, which is associated with spontaneous or action-induced myoclonus and progressive neurodegeneration. Since 2020, 4 families with progressive myoclonic epilepsy-11 [OMIM#618876] have been reported with a very limited spectrum of SEMA6B pathogenic variants. In our study, whole-exome sequencing was used in a proband from a nonconsanguineous Chinese family presenting with growth retardation and recurrent atonic seizures. A deletion mutation (c.1960_1978del, p.Leu654Argfs*25) in the last exon of SEMA6B was detected, which is a de Novo variant and pathogenic. The new genetic evidence we reported here strengthened the gene-disease relationship, and the gene curation level between SEMA6B and progressive myoclonic epilepsy-11 became “strong” following the ClinGen SOP. Therefore, the results of this study broaden the mutation spectrum of SEMA6B in different ethnic groups and strengthen the gene-disease relationship between SEMA6B and progressive myoclonic epilepsy-11.