A novel KCNC1 gain-of-function variant causing developmental and epileptic encephalopathy: "Precision medicine" approach with fluoxetine.

Variable phenotypes, including developmental encephalopathy with (DEE) or without seizures and myoclonic epilepsy and ataxia due to potassium channel mutation, are caused by pathogenetic variants in KCNC1, encoding for Kv3.1 channel subunits. In vitro, channels carrying most KCNC1 pathogenic variants display loss-of-function features. Here, we describe a child affected by DEE with fever-triggered seizures, caused by a novel de novo heterozygous missense KCNC1 variant (c.1273G>A; V425M). Patch-clamp recordings in transiently transfected CHO cells revealed that, compared to wild-type, Kv3.1 V425M currents (1) were larger, with membrane potentials between -40 and +40 mV; (2) displayed a hyperpolarizing shift in activation gating; (3) failed to inactivate; and (4) had slower activation and deactivation kinetics, consistent with a mixed functional pattern with prevalent gain-of-function effects. Exposure to the antidepressant drug fluoxetine inhibited currents expressed by both wild-type and mutant Kv3.1 channels. Treatment of the proband with fluoxetine led to a rapid and prolonged clinical amelioration, with the disappearance of seizures and an improvement in balance, gross motor skills, and oculomotor coordination. These results suggest that drug repurposing based on the specific genetic defect may provide an effective personalized treatment for KCNC1-related DEEs.

Neurological soft signs are increased in migraine without aura: relationship with the affective status.

INTRODUCTION: Neurological soft signs (NSS) are subtle non-localizing sensorimotor abnormalities initially reported as increased in primary headache patients. The aims of this study were confirming with full power NSS increased expression in migraine and, collaterally, determining if psychiatric traits or white matter lesions at brain imaging could influence this result. METHODS: Forty drug-free episodic migraine outpatients (MH) were recruited with 40 matched controls. NSS were determined by the 16-item Heidelberg scale; depression, anxiety and QoL by the HAM-D; the STAI-X1/X2; and the SF36, respectively. The Fazekas scale on brain MR studies was applied in n = 32 MH, unravelling deep white matter signal alterations (DWM). MH characteristics, including the headache disability inventory (HDI), were recorded. RESULTS: NSS were 46% increased in MH vs. controls (p = 0.0001). HAM-D and STAI-X1/X2 were increased in MH, while SF36 was unchanged, but they all failed to influence NSS, just as MH characteristics. NSS scores were increased in MH-DWM + (n = 11, + 85%) vs. MH-DWM - (n = 21, + 27%) vs. controls (p < 0.0001). NSS increased expression in MH was influenced by DWM, while psychiatric traits and headache characteristics failed to do so. DISCUSSION/CONCLUSIONS: NSS are increased in MH and probably not influenced by the affective status, possibly marking a dysfunction within the cerebellar-thalamic-prefrontal circuit that may deserve further attention from the prognostic point of view.

Early Parkinsonism in a Senegalese girl with Lafora disease.

We report the atypical presentation of Lafora disease in a Senegalese girl carrying the homozygous variant, c.560A>C, in the NHLRC1 gene. At 13 years, the patient developed myoclonic and visual seizures, progressive psychomotor slowing, and cognitive decline. At 14 years, a neurological examination showed severe hypomimia, bradykinesia, rigidity and low-amplitude myoclonic jerks. Flash-visual and somatosensory evoked potentials showed an increased amplitude of the cortical components, while an electroretinogram showed attenuated responses. An EEG showed diffuse polyspikes associated with positive-negative jerks as well as posterior slow waves and irregular spikes. The electroclinical picture suggested the diagnosis of Lafora disease regarding the association of visual seizures, cognitive deterioration, and action myoclonus, together with the EEG and evoked potential findings. Two uncommon findings were the prominence of extrapyramidal signs in the early stage of disease (which are rarely reported) and attenuation of electroretinal responses. We consider that Lafora disease should be included in the diagnostic work-up for juvenile Parkinsonism, when associated with epilepsy.