A systematic literature review on the global epidemiology of Dravet syndrome and Lennox-Gastaut syndrome: Prevalence, incidence, diagnosis, and mortality.

Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS) are rare developmental and epileptic encephalopathies associated with seizure and nonseizure symptoms. A comprehensive understanding of how many individuals are affected globally, the diagnostic journey they face, and the extent of mortality associated with these conditions is lacking. Here, we summarize and evaluate published data on the epidemiology of DS and LGS in terms of prevalence, incidence, diagnosis, genetic mutations, and mortality and sudden unexpected death in epilepsy (SUDEP) rates. The full study protocol is registered on PROSPERO (CRD42022316930). After screening 2172 deduplicated records, 91 unique records were included; 67 provided data on DS only, 17 provided data on LGS only, and seven provided data on both. Case definitions varied considerably across studies, particularly for LGS. Incidence and prevalence estimates per 100 000 individuals were generally higher for LGS than for DS (LGS: incidence proportion = 14.5-28, prevalence = 5.8-60.8; DS: incidence proportion = 2.2-6.5, prevalence = 1.2-6.5). Diagnostic delay was frequently reported for LGS, with a wider age range at diagnosis reported than for DS (DS, 1.6-9.2 years; LGS, 2-15 years). Genetic screening data were reported by 63 studies; all screened for SCN1A variants, and only one study specifically focused on individuals with LGS. Individuals with DS had a higher mortality estimate per 1000 person-years than individuals with LGS (DS, 15.84; LGS, 6.12) and a lower median age at death. SUDEP was the most frequently reported cause of death for individuals with DS. Only four studies reported mortality information for LGS, none of which included SUDEP. This systematic review highlights the paucity of epidemiological data available for DS and especially LGS, demonstrating the need for further research and adoption of standardized diagnostic criteria.

Chronic partial TrkB activation reduces seizures and mortality in a mouse model of Dravet syndrome.

Dravet syndrome (DS) is one of the most severe childhood epilepsies, characterized by intractable seizures and comorbidities including cognitive and social dysfunction and high premature mortality. DS is mainly caused by loss-of-function mutations in the Scn1a gene encoding Nav1.1 that is predominantly expressed in inhibitory parvalbumin-containing (PV) interneurons. Decreased Nav1.1 impairs PV cell function, contributing to DS phenotypes. Effective pharmacological therapy that targets defective PV interneurons is not available. The known role of brain-derived neurotrophic factor (BDNF) in the development and maintenance of interneurons, together with our previous results showing improved PV interneuronal function and antiepileptogenic effects of a TrkB receptor agonist in a posttraumatic epilepsy model, led to the hypothesis that early treatment with a TrkB receptor agonist might prevent or reduce seizure activity in DS mice. To test this hypothesis, we treated DS mice with LM22A-4 (LM), a partial agonist at the BDNF TrkB receptor, for 7 d starting at postnatal day 13 (P13), before the onset of spontaneous seizures. Results from immunohistochemistry, Western blot, whole-cell patch-clamp recording, and in vivo seizure monitoring showed that LM treatment increased the number of perisomatic PV interneuronal synapses around cortical pyramidal cells in layer V, upregulated Nav1.1 in PV neurons, increased inhibitory synaptic transmission, and decreased seizures and the mortality rate in DS mice. The results suggest that early treatment with a partial TrkB receptor agonist may be a promising therapeutic approach to enhance PV interneuron function and reduce epileptogenesis and premature death in DS.

Scn8a Antisense Oligonucleotide Is Protective in Mouse Models of SCN8A Encephalopathy and Dravet Syndrome.

OBJECTIVE: SCN8A encephalopathy is a developmental and epileptic encephalopathy (DEE) caused by de novo gain-of-function mutations of sodium channel Nav 1.6 that result in neuronal hyperactivity. Affected individuals exhibit early onset drug-resistant seizures, developmental delay, and cognitive impairment. This study was carried out to determine whether reducing the abundance of the Scn8a transcript with an antisense oligonucleotide (ASO) would delay seizure onset and prolong survival in a mouse model of SCN8A encephalopathy. METHODS: ASO treatment was tested in a conditional mouse model with Cre-dependent expression of the pathogenic patient SCN8A mutation p.Arg1872Trp (R1872W). This model exhibits early onset of seizures, rapid progression, and 100% penetrance. An Scn1a +/- haploinsufficient mouse model of Dravet syndrome was also treated. ASO was administered by intracerebroventricular injection at postnatal day 2, followed in some cases by stereotactic injection at postnatal day 30. RESULTS: We observed a dose-dependent increase in length of survival from 15 to 65 days in the Scn8a-R1872W/+ mice treated with ASO. Electroencephalographic recordings were normal prior to seizure onset. Weight gain and activity in an open field were unaffected, but treated mice were less active in a wheel running assay. A single treatment with Scn8a ASO extended survival of Dravet syndrome mice from 3 weeks to >5 months. INTERPRETATION: Reduction of Scn8a transcript by 25 to 50% delayed seizure onset and lethality in mouse models of SCN8A encephalopathy and Dravet syndrome. Reduction of SCN8A transcript is a promising approach to treatment of intractable childhood epilepsies. Ann Neurol 2020;87:339-346.

Two autopsy cases of sudden unexpected death from Dravet syndrome with novel de novo SCN1A variants.

AIM: Dravet syndrome (DS) is characterized by high epilepsy-related premature mortality with a markedly young age at death, however, autopsy report of sudden unexpected death with DS has been fewer than expected. METHODS: We report two autopsy cases with sudden unexpected death from DS. Case 1 was a 13-year-old male who drowned in a bathtub, and Case 2 was a 3-year-old female who died while sleeping. In Case 1, the blood concentration of the anticonvulsant, valproic acid, was below the recommended therapeutic range. Neuropathological investigation and genetic analysis of 402 cardiovascular disease-related and 146 epilepsy-related genes by next generation sequencing were applied. RESULTS: No significant neuronal loss with gliosis was observed in the brain of either patient. Although possible mild malformations of cortical development were found in both, the degree thereof was similar to that of age-matched controls. Genetic analysis identified a novel variant in SCN1A intron 23 (c.4477-3T > C) in Case 1 that falls outside of the minor splicing consensus sequence. In vitro splicing functional assays with minigene constructs revealed that this intronic variant leads to a 2-bp insertion immediately before exon 24 that results in protein truncation. Similarly, a novel de novo missense mutation of unknown significance, SCN1A_Arg187Pro, was identified in Case 2. In both cases, we also identified cardiomyopathy-related variants classified as likely pathogenic; however, the effect of these variants at death was minimal because there was an absence of pathological change indicating inherited cardiomyopathy. CONCLUSION: The present cases emphasize the need for multifaceted examination of DS cases so as to obtain a definitive autopsy diagnosis and to explore the mechanism of sudden unexpected death.

Delayed maturation of GABAergic signaling in the Scn1a and Scn1b mouse models of Dravet Syndrome.

Dravet syndrome (DS) is a catastrophic developmental and epileptic encephalopathy characterized by severe, pharmacoresistant seizures and the highest risk of Sudden Unexpected Death in Epilepsy (SUDEP) of all epilepsy syndromes. Here, we investigated the time course of maturation of neuronal GABAergic signaling in the Scn1b-/- and Scn1a+/- mouse models of DS. We found that GABAergic signaling remains immature in both DS models, with a depolarized reversal potential for GABAA-evoked currents compared to wildtype in the third postnatal week. Treatment of Scn1b-/- mice with bumetanide resulted in a delay in SUDEP onset compared to controls in a subset of mice, without prevention of seizure activity or amelioration of failure to thrive. We propose that delayed maturation of GABAergic signaling may contribute to epileptogenesis in SCN1B- and SCN1A-linked DS. Thus, targeting the polarity of GABAergic signaling in brain may be an effective therapeutic strategy to reduce SUDEP risk in DS.

Fatal Cerebral Edema With Status Epilepticus in Children With Dravet Syndrome: Report of 5 Cases.

Dravet syndrome (DS) is a well-recognized developmental and epileptic encephalopathy associated with SCN1A mutations and 15% mortality by 20 years. Although over half of cases succumb to sudden unexpected death in epilepsy, the cause of death in the remainder is poorly defined. We describe the clinical, radiologic, and pathologic characteristics of a cohort of children with DS and SCN1A mutations who developed fatal cerebral edema causing mass effect after fever-associated status epilepticus. Cases were identified from a review of children with DS enrolled in the Epilepsy Genetics Research Program at The University of Melbourne, Austin Health, who died after fever-associated status epilepticus. Five children were identified, all of whom presented with fever-associated convulsive status epilepticus, developed severe brain swelling, and died. All had de novo SCN1A mutations. Fever of 40°C or greater was measured in all cases. Signs of brainstem dysfunction, indicating cerebral herniation, were first noted 3 to 5 days after initial presentation in 4 patients, though were apparent as early as 24 hours in 1 case. When MRI was performed early in a patient's course, focal regions of cortical diffusion restriction were noted. Later MRI studies demonstrated diffuse cytotoxic edema, with severe cerebral herniation. Postmortem studies revealed diffuse brain edema and widespread neuronal damage. Laminar necrosis was seen in 1 case. Cerebral edema leading to fatal brain herniation is an important, previously unreported sequela of status epilepticus in children with DS. This potentially remediable complication may be a significant contributor to the early mortality of DS.

Mortality in Dravet syndrome.

We measured the mortality rate and the rate of Sudden Unexpected Death in Epilepsy (SUDEP) in Dravet Syndrome (DS). We studied a cohort of 100 consecutively recruited, unrelated patients with DS; 87 had SCN1A mutations. Living cases had a median follow-up of 17 years. Seventeen patients died, at a median age of seven years (inter-quartile range 3-11 years) with causes of death: 10 SUDEP, four status epilepticus, two drowning and one asphyxia. The SUDEP classification included three Definite, one Definite Plus and six Probable. The Dravet-specific mortality rate/1000-person-years was 15.84 (98% CI 9.01-27.85). The Dravet-specific SUDEP rate was 9.32/1000-person-years (98% CI 4.46-19.45). The Dravet-specific SUDEP rate is the only documented syndrome-specific SUDEP rate. SUDEP in DS occurs mainly in childhood. It is also the highest SUDEP rate, considerably higher than the recent 5.1 SUDEP rate/1000-person-years for adults with refractory epilepsy.

Mortality in Dravet syndrome: A review.

INTRODUCTION: Premature mortality is a major issue in Dravet syndrome (DS). To improve understanding of DS premature mortality, we conducted a comprehensive literature search with a particular emphasis on SUDEP. METHODS: We searched PubMed, Embase, Web of Science, Cochrane, CENTRAL, CINAHL, PsycINFO, Academic Search Premier, and ScienceDirect on the following terms: "Dravet syndrome", "severe myoclonic epilepsy", "SMEI", "mortality", "survivors", "prognosis", and "death". DS cases or cohorts studies reporting mortality were included. RESULTS: The search yielded 676 articles and 86 meeting abstracts. After removing duplicates and screening titles and abstracts, full text of 73 articles was reviewed. Only 28 articles and six meeting abstracts met inclusion criteria. Five articles and four meeting abstracts were excluded, as the case(s) were also described elsewhere. After checking the references, five additional studies were included. The 30 items reported 177 unique cases. Sudden unexpected death in epilepsy was the likely cause in nearly half of the cases (n=87, 49%), followed by status epilepticus (n=56, 32%). Drowning or accidental death was reported in 14 cases (8%), infections in 9 (5%), other causes in six (3%), and unknown in five (3%). Age at death was reported for 142 of the 177 cases (80%), with a mean age of 8.7±9.8years (SD); 73% died before the age of 10years. DISCUSSION: Dravet syndrome is characterized by high epilepsy-related premature mortality and a marked young age at death. Sudden unexpected death in epilepsy is the leading reported cause of death in DS, accounting for nearly half of all deaths. The cause of this excess mortality remains elusive but may be explained by epilepsy severity, as well as genetic susceptibility to SUDEP.

Mosaic mutations in early-onset genetic diseases.

PURPOSE: An emerging approach in medical genetics is to identify de novo mutations in patients with severe early-onset genetic disease that are absent in population controls and in the patient's parents. This approach, however, frequently misses post-zygotic "mosaic" mutations that are present in only a portion of the healthy parents' cells and are transmitted to offspring. METHODS: We constructed a mosaic transmission screen for variants that have an ~50% alternative allele ratio in the proband but are significantly less than 50% in the transmitting parent. We applied it to two family-based genetic disease cohorts consisting of 9 cases of sudden unexplained death in childhood (SUDC) and 338 previously published cases of epileptic encephalopathy. RESULTS: The screen identified six parental-mosaic transmissions across the two cohorts. The resultant rate of ~0.02 identified transmissions per trio is far lower than that of de novo mutations. Among these transmissions were two likely disease-causing mutations: an SCN1A mutation transmitted to an SUDC proband and her sibling with Dravet syndrome, as well as an SLC6A1 mutation in a proband with epileptic encephalopathy. CONCLUSION: These results highlight explicit screening for mosaic mutations as an important complement to the established approach of screening for de novo mutations.Genet Med 18 7, 746-749.

Carbamazepine and oxcarbazepine in adult patients with Dravet syndrome: Friend or foe?

PURPOSE: In newly diagnosed patients with Dravet syndrome sodium channel blockers are usually avoided. However, in many adult patients the diagnosis was made long after the initiation of therapy. The purpose of our study was to acquire information concerning the potential risks and benefits of (ox)carba(ma)zepine withdrawal in adult patients with genetically confirmed Dravet syndrome. METHOD: We identified 16 adults with Dravet syndrome, living in a tertiary care facility for people with epilepsy and an intellectual disability. We reviewed clinical history, genetic findings, the type and duration of sodium channels blockers that were used, seizure types and frequency, and the effect of a change in these medications. RESULTS: The study population consisted of 9 men and 7 women. Median age was 35 years (range 20-61 years). An attempt to withdraw carbamazepine (CBZ) was made in 9 patients. In 3 of these patients an increase in tonic-clonic seizures was observed. An attempt to withdraw oxcarbazepine (OXC) was made in 3 patients, leading to a complete stop in 2 patients. 3 of the 4 deaths in the withdrawal-group were related to epilepsy. CONCLUSION: In adult patients with Dravet syndrome withdrawal of CBZ or OXC is not without risks. We suggest that (ox)carba(ma)zepine withdrawal should be considered in these patients but only if there is a good reason to do so and only if they are closely monitored.

Sudden death in epilepsy: of mice and men.

A 20-year-old man with intellectual disability and intractable multifocal epilepsy presented to a neurologist for further evaluation and management. His seizures began at 4 months, the night after his first DPT vaccine, and he continued to have frequent tonic-clonic seizures throughout his life. Several weeks after his visit, he was found facedown on the floor, dead, by his family. His autopsy was unremarkable, but genetic testing revealed a frame shift mutation in SCN1A, consistent with severe myoclonic epilepsy of infancy (Dravet syndrome).

Sudden unexpected death in a mouse model of Dravet syndrome.

Sudden unexpected death in epilepsy (SUDEP) is the most common cause of death in intractable epilepsies, but physiological mechanisms that lead to SUDEP are unknown. Dravet syndrome (DS) is an infantile-onset intractable epilepsy caused by heterozygous loss-of-function mutations in the SCN1A gene, which encodes brain type-I voltage-gated sodium channel NaV1.1. We studied the mechanism of premature death in Scn1a heterozygous KO mice and conditional brain- and cardiac-specific KOs. Video monitoring demonstrated that SUDEP occurred immediately following generalized tonic-clonic seizures. A history of multiple seizures was a strong risk factor for SUDEP. Combined video-electroencephalography-electrocardiography revealed suppressed interictal resting heart-rate variability and episodes of ictal bradycardia associated with the tonic phases of generalized tonic-clonic seizures. Prolonged atropine-sensitive ictal bradycardia preceded SUDEP. Similar studies in conditional KO mice demonstrated that brain, but not cardiac, KO of Scn1a produced cardiac and SUDEP phenotypes similar to those found in DS mice. Atropine or N-methyl scopolamine treatment reduced the incidence of ictal bradycardia and SUDEP in DS mice. These findings suggest that SUDEP is caused by apparent parasympathetic hyperactivity immediately following tonic-clonic seizures in DS mice, which leads to lethal bradycardia and electrical dysfunction of the ventricle. These results have important implications for prevention of SUDEP in DS patients.

Retrospective multiinstitutional study of the prevalence of early death in Dravet syndrome.

PURPOSE: A questionnaire survey was conducted in Japan to investigate the causes and prevalence of death related to Dravet syndrome. METHODS: A questionnaire was delivered to 246 hospitals at which physicians were treating childhood epilepsy to gain information about the total number of patients with Dravet syndrome and their prevalence of early death. KEY FINDINGS: Responses to the survey were collected from 91 hospitals, and a total of 63 of 623 patients with Dravet syndrome died. Data from 59 of these patients were analyzed. The patients' ages at death ranged from 13 months to 24 years and 11 months, with a median age of 6 years and 8 months. The analysis showed that the risk of mortality remained high up to approximately 12 years of age. The causes of mortality included sudden death in 31 patients (53%), acute encephalopathy with status epilepticus (SE) in 21 patients (36%), drowning in 6 patients (10%), and acute hepatopathy in one patient (1%). The incidence of sudden death reached a first peak at 1-3 years of age and reached a second peak at 18 years and older. In contrast, the incidence of acute encephalopathy with SE reached a sharp peak at 6 years of age. Seven of 10 patients who underwent an SCN1A mutation analysis exhibited positive mutations without a specific mutation site. SIGNIFICANCE: In the present study, the prevalence of Dravet syndrome-related mortality was 10.1%. The incidence of sudden death and acute encephalopathy with SE was the highest in infancy (1-3 years) and at early school ages (with a peak at 6 years), respectively. After approximately 12 years of age, the risk of mortality declined sharply. Neither the treatment nor the number of seizures was associated with any cause of mortality. In addition, it is difficult to predict which factors lead to a fatal outcome.

Dravet syndrome: the long-term outcome.

Few studies focused on the long-term outcome of Dravet syndrome in adulthood are available in the literature, but all are concordant. In this article, we consider the outcomes of 24 patients followed at the Centre Saint-Paul, Marseille, up to the age of 50, and compare them to the patients reported in the literature. Five patients (20.8%) died, at a mean age of 24.8 years, one by status epilepticus, three by sudden unexpected death in epilepsy (SUDEP), and one of unknown cause. Epileptic seizures tend to become less frequent and less severe after childhood. Fever sensitivity (temperature variations) persists throughout the clinical course of DS, but its impact on seizure frequency and severity is milder than in infancy. Generalized convulsive seizures, mostly reported as generalized tonic-clonic seizures (GTCS), were the only seizure type observed in almost all of the patients, often with a focal onset. They are less frequent than in childhood and mostly nocturnal. Some of these major convulsive seizures have less typical aspects, for example, bilateral or asymmetric tonic posturing, followed in some cases by a tonic vibratory state or clonic movements (Oguni et al., Brain Dev 2001;23:736-748; Akiyama et al., Epilepsia 2010;51:1043-1052). Other seizures like myoclonic seizures, atypical absences, and complex partial seizures (CPS) are less common in adulthood: Among our 24 patients, only 6 had atypical absences, and one myoclonic and one complex focal seizures. Electroencephalography (EEG) also changes with age but is still multiple and heterogenous, interictally and ictally. Photosensitivity and pattern sensitivity also showed a tendency to disappear before the age of 20. Motor abnormalities are common. Cerebellar features, including ataxia, dysarthria, intention tremor, and eye movement disorder, become more prominent. Walking is markedly impaired, often due to orthopedic signs such as kyphosis, kyphoscoliosis, flat feet, or claw feet. This symptomatology was minor during childhood and worsened during and after adolescence, despite physiotherapy. Mental retardation ranged from moderate to severe, with predominance of language impairment, and some patients had a major personality disorder, labeled autistic or psychotic. Dependency in adulthood is nearly constant: Only 3 of our 24 adult patients lived independently.

Mortality in Dravet syndrome: search for risk factors in Japanese patients.

A questionnaire survey was conducted in Japan to investigate the causes and prevalence of death related to Dravet syndrome. The questionnaire was delivered to 246 hospitals at which physicians were treating childhood epilepsy to gain information about the total number of patients with Dravet syndrome and the prevalence of early death due to the disorder. Responses to the survey were collected from 91 hospitals, and a total of 63 of 623 patients with Dravet syndrome had died. Data from 59 of these patients were analyzed. The age at death for these patients ranged from 13 months to 24 years and 11 months, with a median age of 6 years and 8 months. The causes of mortality included sudden death in 31 patients (53%), acute encephalopathy with status epilepticus (SE) in 21 patients (36%), drowning in 6 patients (10%), and other causes in one patient (1%). The incidence of sudden death reached a first peak at 1-3 years of age and a second peak at 18 years and older. In contrast, the incidence of acute encephalopathy with SE reached a peak at 6 years of age. Seven of the 10 patients who underwent SCN1A mutation analysis exhibited positive mutations but exhibited no consistent phenotype. The prevalence of Dravet syndrome-related mortality was 10.1%. The incidence of sudden death and acute encephalopathy with SE was higher in infancy (1-3 years) and at early school ages (with a peak at 6 years), respectively. Neither the treatment nor the number of seizures was associated with any cause of mortality. Factors leading to a fatal outcome are difficult to predict.

Dravet syndrome and parent associations: the IDEA League experience with comorbid conditions, mortality, management, adaptation, and grief.

The advent of social networking via the Internet and the commercial availability of tests for SCN1A mutations permitted the rapid development and growth of parent-led associations that provide advocacy and support, as well as promote education and research regarding Dravet syndrome (DS) in the last 10 years. The International Dravet syndrome Epilepsy Action League (IDEA League) is a partnership of parents and professionals united in the purpose of creating greater awareness and understanding of DS. In 2004, parents in the IDEA League support network began to collect data from families about their children with DS in order to investigate observations that, in addition to epilepsy, many of the children seemed to share similar problems. The information gained suggests comorbid conditions and raises many hypotheses for further research. The process has led to more rigorous formal studies and an increased understanding of the clinical spectrum of DS. There is an urgent need for collaborative research, comprehensive care, and professional and family education. Mortality appears high, primarily due to sudden unexplained death in epilepsy (SUDEP) and status epilepticus (SE). Most parents wish direct discussions with their child's physician about mortality. The high risk of death and the many other stresses related to DS result in recurrent grief and loss for patients and families and highlights their need for additional advocacy and support.

A case of SUDEP in a patient with Dravet syndrome with SCN1A mutation.

A boy with a clinical history of pharmacologically resistant Dravet syndrome died suddenly after falling asleep. The autopsy concluded that the cause of death was sudden unexpected death in epilepsy (SUDEP). Postmortem molecular analysis of the SCN1A gene by multiplex ligation-dependent probe amplification (MLPA), high-resolution melting curve analysis (HRMCA), and sequencing revealed a frameshift duplication of adenosine at position 504. The incidence of this mutation is discussed as a potential cause of SUDEP.

A functional null mutation of SCN1B in a patient with Dravet syndrome.

Dravet syndrome (also called severe myoclonic epilepsy of infancy) is one of the most severe forms of childhood epilepsy. Most patients have heterozygous mutations in SCN1A, encoding voltage-gated sodium channel Na(v)1.1 alpha subunits. Sodium channels are modulated by beta1 subunits, encoded by SCN1B, a gene also linked to epilepsy. Here we report the first patient with Dravet syndrome associated with a recessive mutation in SCN1B (p.R125C). Biochemical characterization of p.R125C in a heterologous system demonstrated little to no cell surface expression despite normal total cellular expression. This occurred regardless of coexpression of Na(v)1.1 alpha subunits. Because the patient was homozygous for the mutation, these data suggest a functional SCN1B null phenotype. To understand the consequences of the lack of beta1 cell surface expression in vivo, hippocampal slice recordings were performed in Scn1b(-/-) versus Scn1b(+/+) mice. Scn1b(-/-) CA3 neurons fired evoked action potentials with a significantly higher peak voltage and significantly greater amplitude compared with wild type. However, in contrast to the Scn1a(+/-) model of Dravet syndrome, we found no measurable differences in sodium current density in acutely dissociated CA3 hippocampal neurons. Whereas Scn1b(-/-) mice seize spontaneously, the seizure susceptibility of Scn1b(+/-) mice was similar to wild type, suggesting that, like the parents of this patient, one functional SCN1B allele is sufficient for normal control of electrical excitability. We conclude that SCN1B p.R125C is an autosomal recessive cause of Dravet syndrome through functional gene inactivation.

Cerebrospinal fluid pterins and neurotransmitters in early severe epileptic encephalopathies.

Early-onset epileptic encephalopathies are devastating conditions. Little is known about pathophysiology and biological markers. We aimed to identify a relationship between the type and prognosis of epileptic encephalopathies starting in infancy and the cerebrospinal fluid profile of pterins and neurotransmitters. Cerebrospinal fluid samples of 23 infants with epileptic encephalopathies were analysed for biogenic amine metabolites (homovanillic and 5-hydroxyindoleacetic acids), and pterins (neopterin and biopterin). West syndrome, early-infantile epileptic encephalopathy with suppression-bursts or Ohtahara syndrome, severe epilepsy with multiple independent spike foci and partial epilepsy with multiple independent spike foci were the four types of epileptic encephalopathy studied. We report clinical, electroencephalographic, neuroimaging and follow-up data. Among the 23 patients studied, 7 had high neopterin levels. Four of them had partial epilepsy with multiple independent spike foci. High neopterin values were associated with mortality (chi square = 7.304, p = 0.007). 5-Hydroxyindoleacetic acid levels were above reference values in three patients, two with partial epilepsy with multiple independent spike foci and one with West syndrome. Homovanillic acid was normal in almost all infants studied. In conclusion, high neopterin levels suggest a cellular immune activation in the central nervous system of these infants, with apparent prognosis implications.