Epilepsy and the immune system: is there a link?

The concept that the immune system plays a role in the epileptogenic process of some epileptic syndromes was first proposed more than 20 years ago. Since then, numerous studies have reported on the existence of a variety of immunological alterations in epileptic patients, on the observation of favourable responses of refractory epilepsy syndromes to immunomodulatory treatment, and on the association of certain well-known immune-mediated disease states with epilepsy. This review comprehensively recapitulates the currently available evidence supporting or arguing against the possible involvement of the immune system in the pathogenesis of certain types of epilepsy. It is concluded that an abundance of facts is in support of this concept and that further studies should be directed at substantiating the pathogenic significance of (auto)immune responses in certain types of epilepsy. Current progress in the functional and molecular immunological research techniques will indisputably contribute to the elucidation of this link.

Clinical predictors for outcome in infants with epilepsy.

In this prospective study, the clinical parameters predictive for the outcome in infants with onset of epilepsy below 12 months of age (n = 60) were determined. At the end of the follow-up period, patients were included in a symptomatic or idiopathic group. In approximately 60% of all children, epilepsy could be controlled with standard antiepileptic monotherapy. The epilepsy was more difficult to control in the symptomatic group, reflected by the larger number of drug switches during follow-up. Seizure outcome was not influenced by age of onset, type of seizures, or electroencephalographic abnormalities at the epilepsy onset. Developmental outcome was significantly worse in the symptomatic group. In the idiopathic group, the control of epilepsy was the major developmental outcome factor, indicating a possible deleterious effect of seizures on brain development in that group.

Clinical correlations of mutations in the SCN1A gene: from febrile seizures to severe myoclonic epilepsy in infancy.

Mutations in the alpha-subunit of the first neuronal sodium channel gene SCN1A have been described in isolated patients with severe myoclonic epilepsy in infancy or Dravet syndrome and in families with generalized epilepsy with febrile seizures plus. To find phenotype/genotype correlations, we reviewed all published cases of mutations in SCN1A in addition to four new patients reported here. A total of 60 mutations were observed. Approximately 52% (31/60) are truncating mutations correlating with de novo cases of classical Dravet syndrome in 32 of 34 (94%) patients. Missense mutations in the pore-forming part constitute 27% (16/60) and correspond to a classical type in 12 of 16 (75%) patients. Missense mutations in the voltage sensor were present in 12% (7/60) and correlate with a clinical picture ranging from febrile seizures plus to severe myoclonic epilepsy in infancy. Outside these regions missense mutations are rare and account for only 10% (6/60), corresponding mostly with febrile seizures plus. These results illustrate that the clinical spectrum of SCN1A mutations ranges from febrile seizures, febrile seizures plus, over a milder type to the classical form of severe myoclonic epilepsy in infancy, and confirm the clinical experience that severe myoclonic epilepsy in infancy is the most severe form on this spectrum.

Visual perception in preterm children: what are we currently measuring?

Over the past two decades, cerebral visual impairment has been recognized as a principal deficit in preterm children, and in particular those with cerebral palsy. We review the current knowledge of visual processing deficits in these children, and provide an overview of the tools for assessing cerebral visual impairment. Commercially available instruments are usually directed at evaluating visuospatial skills rather than detecting object recognition difficulties. Particularly in children aged 3 years or younger and in children with multiple handicaps, cerebral visual impairment is difficult to diagnose. This difficulty may be attributable to limitations specific to the instrument, such as a test that is inappropriate for age, or to child-specific limitations such as motor impairment or speech delay. We therefore include an overview of relevant neuroimaging findings reported in these children, focusing on the most recent imaging modalities. Novel techniques such as diffusion tensor imaging may provide sensitive markers of cerebral visual impairment in situations where clinical diagnosis is difficult, and such approaches may allow for early intervention.

Mutations in POMT1 are found in a minority of patients with Walker-Warburg syndrome.

Walker-Warburg syndrome (WWS) is an autosomal recessive disorder of infancy characterized by hydrocephalus, agyria, retinal dysplasia, congenital muscular dystrophy, and over migration of neurons through a disrupted pial surface resulting in leptomeningeal heterotopia. Although previous work identified mutations in the o-mannosyl transferase, POMT1, in 6 out of 30 WWS families [Beltran-Valero de Bernabe et al., 2002], the incidence of POMT1 mutations in WWS is not known. We sequenced the entire coding region of POMT1 in 30 consecutive, unselected patients with classic WWS. Two novel heterozygous mutations were found in two patients from non-consanguineous parents, whereas 28 other patients failed to show any POMT1 mutations. One patient was found to be heterozygous for a transition, g.1233T > A, which predicts p.Y352X. A second patient was found also to be heterozygous for a transition g.1790C > G, which predicts p.S537R. As an additional determination of the frequency of the POMT1 mutations in WWS, we tested for linkage of WWS to POMT1 in six consanguineous families. All six demonstrated heterozygosity and negative LOD scores at the POMT1 locus. From these data we show that POMT1 is an uncommon cause of WWS, the incidence of coding region mutations in this population of WWS being less than 7%. We conclude that while the incidence of POMT1 mutations in WWS can be as high as 20% as reported by Beltran-Valero de Bernabe et al. [2002] and it can be as low as approximately 7%, as reported here.