[A patient with an early diagnosis of PCDH19-related epilepsy].

An abnormality in PCDH19 causes intractable early-onset epilepsy limited to females, and its significance in pediatric epilepsy is currently increasing. We report the case of a girl with an early diagnosis of PCDH19-related epilepsy. Focal seizures, consisting of eye deviation and asymmetrical tonic posturing, first appeared in clusters at the age of 5 months. Although each seizure was brief (less than a few minutes), seizures occurred in clusters. Cluster was observed at ages of 7, 10, 11, 14, and 19 months, respectively, and all were intractable to multiple treatments. Each cluster continued for 3 days to 2 weeks. However, no seizures occurred outsides the clusters. The pattern of seizure occurrences was characteristic of PCDH19-related epilepsy, which we first suspected when the patient was 11 months old. Genetic analysis of PCDH19 revealed two novel missense substitutions: c.1294G≥C (p.D417H) and c.1786G≥T (p.D596Y). Her psychomotor development was normal at the last follow-up at age of 1 year and 9 months. Currently, the pathogenesis and best treatments of PCDH19-related epilepsy remain unclear. However, to provide correct diagnosis and genetic counseling, and to avoid overtreatments, the possibility of this disease should be considered early in girls with intractable seizure clusters which starting during infancy to early childhood.

Hemizygous FLNA variant in West syndrome without periventricular nodular heterotopia.

Pathogenic FLNA variants can be identified in patients with seizures accompanied by periventricular nodular heterotopia (PVNH). It is unusual to find FLNA aberrations in epileptic patients without PVNH on brain imaging. We report a boy with cryptogenic West syndrome followed by refractory seizures and psychomotor delay. We performed whole-exome sequencing and identified a de novo missense variant in FLNA. It is noteworthy that this patient showed no PVNH. As no other pathogenic variants were found in epilepsy-related genes, this FLNA variant likely caused West syndrome but with no PVNH.

Immediate suppression of seizure clusters by corticosteroids in PCDH19 female epilepsy.

PURPOSE: The pathomechanism and treatment of PCDH19 female epilepsy (PCDH19-FE) remain unclear. Here, we report that corticosteroids are effective for control of the seizure clusters or other acute symptoms of PCDH19-FE and argue for the possible involvement of a compromised blood-brain barrier (BBB) in its pathogenesis. METHODS: The efficacy of corticosteroids was retrospectively reviewed in five Japanese patients with PCDH19-FE. The results of antibody assays against the N-methyl-d-aspartate-type glutamate receptor (abs-NR) in serum/cerebrospinal fluid were also compiled. RESULTS: Corticosteroid treatments significantly improved the acute symptoms, including seizure clusters, in all cases, most often immediately after the initial administration. However, the effect was transient, and some seizures recurred within a few weeks, especially in association with fever. Serum and/or cerebrospinal fluid abs-NR were detected in all patients. Target sequences of the detected antibodies were multiple, and the titers tended to decrease over time. In one patient, immunohistochemical analysis using rat hippocampal slices also revealed serum antibodies targeting an unknown epitope in neuronal cytoplasm. CONCLUSION: Our findings imply an involvement of inflammatory processes in the pathogenesis of PCDH19-FE and therapeutic utility for corticosteroids as an adjunctive option in acute treatment. PCDH19 is well expressed in brain microvascular endothelial cells and thus its impairment may cause BBB vulnerability, which may be ameliorated by corticosteroids. The abs-NR detected in our patients may not indicate an autoimmune pathomechanism, but may rather represent non-specific sensitization to degraded neuronal components entering the general circulation, the latter process facilitated by the BBB vulnerability.