Characteristics of patients with benign partial epilepsy in infancy without PRRT2 mutations

Sodium channel blockers are effective for benign infantile epilepsy

OBJECTIVE

To examine the efficacy and tolerance of the antiseizure medications lacosamide (LCM) and levetiracetam (LEV) in patients with benign infantile epilepsy (BIE).

METHODS

The clinical data of 24 children with BIE seen between 2014 and 2020 were collected retrospectively, and treatment, effectiveness, and adverse effects were examined. PRRT2 gene analysis was performed using Sanger sequencing.

RESULTS

Of the 24 children with BIE, 14 were treated with antiseizure medications. PRRT2 gene analysis was performed in 14 children, and mutations were identified in 4, including a pair of siblings. All five children treated with LCM became seizure-free, similar to those treated with carbamazepine. The LCM does was 2 mg/kg/day in all cases. There were no adverse effects in any patient treated with LCM. By contrast, both patients treated with LEV had seizure recurrence. In one patient, LEV was replaced with CBZ, resulting in seizure freedom.

CONCLUSIONS

Low-dose LCM was effective and well tolerated in patients with BIE, whereas LEV was insufficiently effective.

Benign juvenile idiopathic epilepsy in captive Iberian lynx (Lynx pardinus) in the ex situ conservation program (2005-2019)

Background

Benign juvenile idiopathic epilepsy has been described in humans but rarely in animals. The objectives of the study were to describe the clinical signs, clinical data, imaging findings, genetic examinations, treatment, long-term outcome and prognosis in Iberian lynx with juvenile epilepsy. Medical records, video recordings and diagnostic data from 2005 to 2019 were reviewed.

Results

Twenty lynx cubs with early onset of epileptic seizures (ES) from the conservation program were included. The average age at seizure onset was 75 days. Isolated and cluster ES were recorded. Focal ES, focal ES evolving into generalized ES with a stereotypical pattern and generalized ES were observed. All the cubs were normal between episodes, had a normal neurological examination and unremarkable investigations. Phenobarbital was used as a first line antiepileptic drug (AED). ES halted 10 days (0–34) after starting treatment in eight out of twenty cubs (40%). Treatment was discontinued in this group after a mean of 578 days and no further ES were reported (mean follow-up longer than 5 years). Eleven animals (55%) continued on AED treatment for a mean of 1306 days (70–3466). An adult-onset was observed for one lynx (5%). Polytherapy was necessary in seven lynxes (35%). The inheritance pattern observed was compatible with an autosomal recessive condition. Based on this assumption, mating between two identified carriers has been avoided since 2012, which may have contributed to the subsequent decrease in prevalence, with no further cases detected in 2018 and 2019.

Conclusions

Lynx pardinus may have an early onset self-limiting ES syndrome characteristic of benign juvenile idiopathic epilepsy. Information obtained from this study strongly suggests a genetic basis for the here presented epilepsy.

The clinical and genetic spectrum in infants with (an) unprovoked cluster(s) of focal seizures

BACKGROUND

Self-limited (familial) infantile epilepsy (S(F)IE), formerly known as benign (familial) infantile convulsions (B(F)IC), is an infantile cluster epilepsy with in rule a complete recovery. This form of epilepsy is most often caused by variations in the PRRT2 gene (OMIM #605751).

AIM

To describe the clinical and genetic spectrum of sudden onset clusters of focal seizures in infancy.

METHODS

We retrospectively reviewed all individuals, who presented with unprovoked infantile seizures and selected all infants who had unprovoked clustered focal seizures between 1 and 20 months of age. We described the clinical and genetic spectrum of this cohort.

RESULTS

The data of 23 patients from 21 families were collected. All had an initial diagnosis of S(F)IE which was adjusted in 5 individuals. In 12 individuals a pathogenic variation in PRRT2 gene or complete deletion was identified. Pathogenic variants in PCDH19 and KCNQ2 were found in respectively 3 and 1 individuals. One individual had a non-pathogenic variant in ATP1A3 and in 6 others no variants were identified. The mean cluster duration was 2.9 days (range 1-13) (see Table 1). Twelve infants had only one cluster. All patients had focal motor or non-motor seizures, in 12 (52%) followed by bilateral (tonic)clonic seizures. Positive family history was present in 74% of individuals. In 11/12 (92%) tested families, ≥1 family member carried the pathogenic PRRT2 variant. Age of seizure onset (ASO) averaged 6.2 months (range 2-20 months). Age of latest seizure averaged 16 months (range 2-92). In several interictal EEG (electroencephalogram) recordings multifocal spikes or spike-wave abnormalities were detected. Ictal EEG recordings detected primary focal abnormalities.

CONCLUSION

We described 23 individuals with unprovoked cluster(s) of focal seizures at infancy. It appears to be a heterogeneous group. Half of them had a pathogenic variation in PRRT2 gene. Most had only one cluster of seizures. When clusters reoccur frequently, when seizures are more therapy-resistant and when seizures persist beyond the age of 2 years, another diagnosis or causative gene is likely.

Focal seizures and epileptic spasms in a child with Down syndrome from a family with a PRRT2 mutation

We describe a girl with Down syndrome who experienced focal seizures and epileptic spasms during infancy. The patient was diagnosed as having trisomy 21 during the neonatal period. She had focal seizures at five months of age, which were controlled with phenobarbital. However, epileptic spasms appeared at seven months of age in association with hypsarrhythmia. Upon treatment with adrenocorticotropic hormone, her epileptic spasms disappeared. Her younger brother also had focal seizures at five months of age. His development and interictal electroencephalogram were normal. The patient's father had had infantile epilepsy and paroxysmal kinesigenic dyskinesia. We performed a mutation analysis of the PRRT2 gene and found a c.841T>C mutation in the present patient, her father, and in her younger brother. We hypothesized that the focal seizures in our patient were caused by the PRRT2 mutation, whereas the epileptic spasms were attributable to trisomy 21.