Michael Alber

Targeted next generation sequencing as a diagnostic tool in epileptic disorders

Purpose:  Epilepsies have a highly heterogeneous background with a strong genetic contribution. The variety of unspecific and overlapping syndromic and nonsyndromic phenotypes often hampers a clear clinical diagnosis and prevents straightforward genetic testing. Knowing the genetic basis of a patient’s epilepsy can be valuable not only for diagnosis but also for guiding treatment and estimating recurrence risks.

Novel mutations consolidate KCTD7 as a progressive myoclonus epilepsy gene

Background The progressive myoclonus epilepsies (PMEs) comprise a group of clinically and genetically heterogeneous disorders characterised by myoclonus, epilepsy, and neurological deterioration. This study aimed to identify the underlying gene(s) in childhood onset PME patients with unknown molecular genetic background. Methods Homozygosity mapping was applied on genome-wide single nucleotide polymorphism data of 18 Turkish patients. The potassium channel tetramerisation domain-containing 7 (KCTD7) gene, previously associated with PME in a single inbred family, was screened for mutations. The spatiotemporal expression of KCTD7 was assessed in cellular cultures and mouse brain tissue. Results Overlapping homozygosity in 8/18 patients defined a 1.5 Mb segment on 7q11.21 as the major candidate locus. Screening of the positional candidate gene KCTD7 revealed homozygous missense mutations in two of the eight cases. Screening of KCTD7 in a further 132 PME patients revealed four additional mutations (two missense, one in-frame deletion, and one frameshift-causing) in five families. Eight patients presented with myoclonus and epilepsy and one with ataxia, the mean age of onset being 19 months. Within 2 years after onset, progressive loss of mental and motor skills ensued leading to severe dementia and motor handicap. KCTD7 showed cytosolic localisation and predominant neuronal expression, with widespread expression throughout the brain. None of three polypeptides carrying patient missense mutations affected the subcellular distribution of KCTD7. Discussion These data confirm the causality of KCTD7 defects in PME, and imply that KCTD7 mutation screening should be considered in PME patients with onset around 2 years of age followed by rapid mental and motor deterioration.

ARHGEF9 disease: Phenotype clarification and genotype-phenotype correlation

Objective: We aimed to generate a review and description of the phenotypic and genotypic spectra of ARHGEF9 mutations. Methods: Patients with mutations or chromosomal disruptions affecting ARHGEF9 were identified through our clinics and review of the literature. Detailed medical history and examination findings were obtained via a standardized questionnaire, or if this was not possible by reviewing the published phenotypic features. Results: A total of 18 patients (including 5 females) were identified. Six had de novo, 5 had maternally inherited mutations, and 7 had chromosomal disruptions. All females had strongly skewed X-inactivation in favor of the abnormal X-chromosome. Symptoms presented in early childhood with delayed motor development alone or in combination with seizures. Intellectual disability was severe in most and moderate in patients with milder mutations. Males with severe intellectual disability had severe, often intractable, epilepsy and exhibited a particular facial dysmorphism. Patients with mutations in exon 9 affecting the proteins PH domain did not develop epilepsy. Conclusions: ARHGEF9 encodes a crucial neuronal synaptic protein; loss of function of which results in severe intellectual disability, epilepsy, and a particular facial dysmorphism. Loss of only the proteins PH domain function is associated with the absence of epilepsy.

A multinational survey on actual diagnostics and treatment of subacute sclerosing panencephalitis

Subacute sclerosing panencephalitis (SSPE) is a chronic infection of the central nervous system caused by the measles virus (MV). Its prevalence remains high in resource poor countries and is likely to increase in the Northern Europe as vaccination rates decrease. Clinical knowledge of this devastating condition, however, is limited. We therefore conducted this multinational survey summarizing experience obtained from more than 500 patients treated by 24 physicians in seven countries. SSPE should be considered in all patients presenting with otherwise unexplained acquired neurological symptoms. In most patients, the diagnosis will be established by the combination of typical clinical symptoms (characteristic repetitive myoclonic jerks), a strong intrathecal synthesis of antibodies to MV and typical electroencephalogram findings (Radermecker complexes). Whereas the therapeutic use of different antiviral (amantadine, ribavirin) and immunomodulatory drugs (isoprinosine, interferons) and of immunoglobulins has been reported repeatedly, optimum application regimen of these drugs has not been established. This is partly due to the absence of common diagnostic and clinical standards focusing on neurological and psychosocial aspects. Carbamazepine, levetiracetam, and clobazam are the drugs most frequently used to control myoclonic jerks. We have established a consensus on essential laboratory and clinical parameters that should facilitate collaborative studies. Those are urgently needed to improve outcome.

An association between external hydrocephalus in infants and reversible collapse of the venous sinuses.

The etiology of external hydrocephalus is usually ascribed to either a delay in maturation or obstruction of the arachnoid granulations, but the arachnoid granulations are absent in neonates. Venous outflow stenoses, similar to those seen in idiopathic intracranial hypertension (IIH), have been described in external hydrocephalus. A reversible collapse of the sinuses is known to operate in IIH, but collapsible sinuses have not been previously described in infants with external hydrocephalus. Three infants with external hydrocephalus had magnetic resonance venography at differing time points during their illness. The venous sinuses varied in size depending on the cerebrospinal fluid pressure similar to IIH in adults. External hydrocephalus may be analogous to IIH in adults.

Fetal suppression burst pattern in Ohtahara syndrome visualized by fetal magnetoencephalography

Maternal age, y 30.8±4.7 32.4±5.3 26.9±4.8 27.0±1.4 26.81±4.7 27.83±6.6 28.93±6.01 25.4±2.7 Parity Primigravida 19 (28.4) 6 (75.0) 16 (69.6) 1 (50.0) 24 (46.2) 6 (50.0) 11 (35.5) 2 (40.0) Multigravida 48 (71.6) 2 (25.0) 7 (30.4) 1 (50.0) 28 (53.8) 6 (50.0) 20 (64.5) 3 (60.0) Gestational age, wk 39.41±1.3 39.5±1.2 39.22±1.1 38.5±0.7 39.25±1.2 38.58±1.3 38.90±0.9 38.80±1.3 Infant birth weight, g 3428.4±420.9 3444.9±369.5 3480.4±347.5 2915.0±5.4 NA NA NA NA

The phenotype of SCN8A developmental and epileptic encephalopathy

Objective To delineate the electroclinical features of SCN8A infantile developmental and epileptic encephalopathy (EIEE13, OMIM #614558). Methods Twenty-two patients, aged 19 months to 22 years, underwent electroclinical assessment. Results Sixteen of 22 patients had mildly delayed development since birth. Drug-resistant epilepsy started at a median age of 4 months, followed by developmental slowing, pyramidal/extrapyramidal signs (22/22), movement disorders (12/22), cortical blindness (17/22), sialorrhea, and severe gastrointestinal symptoms (15/22), worsening during early childhood and plateauing at age 5 to 9 years. Death occurred in 4 children, following extreme neurologic deterioration, at 22 months to 5.5 years. Nonconvulsive status epilepticus recurred in 14 of 22 patients. The most effective antiepileptic drugs were oxcarbazepine, carbamazepine, phenytoin, and benzodiazepines. EEG showed background deterioration, epileptiform abnormalities with a temporo-occipital predominance, and posterior delta/beta activity correlating with visual impairment. Video-EEG documented focal seizures (FS) (22/22), spasm-like episodes (8/22), cortical myoclonus (8/22), and myoclonic absences (1/22). FS typically clustered and were prolonged (<20 minutes) with (1) cyanosis, hypomotor, and vegetative semiology, sometimes unnoticed, followed by (2) tonic-vibratory and (3) (hemi)-clonic manifestations ± evolution to a bilateral tonic-clonic seizure. FS had posterior-temporal/occipital onset, slowly spreading and sometimes migrating between hemispheres. Brain MRI showed progressive parenchymal atrophy and restriction of the optic radiations. Conclusions: SCN8A developmental and epileptic encephalopathy has strikingly consistent electroclinical features, suggesting a global progressive brain dysfunction primarily affecting the temporo-occipital regions. Both uncontrolled epilepsy and developmental compromise contribute to the profound impairment (increasing risk of death) during early childhood, but stabilization occurs in late childhood.

Rituximab, IVIg, and Tetracosactide (ACTH1–24) Combination Immunotherapy (“RITE-CI”) for Pediatric Opsoclonus-Myoclonus Syndrome: Immunomarkers and Clinical Observations

&NA; Opsoclonus‐myoclonus syndrome (OMS) is a neuroinflammatory disorder with pervasive morbidity that warrants better treatments. Twelve children with moderate/severe OMS (total score 23 ± 6) who did not remit to multiple immunotherapies were evaluated for neuroinflammation in a case‐control study using cerebrospinal fluid (CSF) lymphocyte subset analysis by flow cytometry, chemokine/cytokine analysis by enzyme‐linked immunoadsorption assay (ELISA), and oligoclonal bands by immunofixation with isoelectric focusing. Observations made on empirical treatment with rituximab, IVIg, and tetracosactide combination immunotherapy (coined “RITE‐CI”) were analyzed. All of the patients tested for multiple inflammatory markers were positive; 75% had ≥3 CSF markers. Fifty percent had CSF oligoclonal bands; 58%, B cell expansion; and 50 to 100%, elevated concentrations of multiple chemokines and neuronal/axonal marker neurofilament light chain. After RITE‐CI, total score dropped significantly in the group (−85%, p < 0.0001) from moderate to trace, and by 2 to 4 severity categories in each patient. The 24‐week schedule was well tolerated and clinically effective for moderate or severe OMS, as were other schedules. RITE‐CI is feasible and effective as rescue therapy and presents an initial option for children with moderate/severe OMS. Though preliminary, the schedule can be adjusted to patient severity, propensity for relapse, and other factors.