X-Linked Epilepsies: A Narrative Review.

X-linked epilepsies are a heterogeneous group of epileptic conditions, which often overlap with X-linked intellectual disability. To date, various X-linked genes responsible for epilepsy syndromes and/or developmental and epileptic encephalopathies have been recognized. The electro-clinical phenotype is well described for some genes in which epilepsy represents the core symptom, while less phenotypic details have been reported for other recently identified genes. In this review, we comprehensively describe the main features of both X-linked epileptic syndromes thoroughly characterized to date (PCDH19-related DEE, CDKL5-related DEE, MECP2-related disorders), forms of epilepsy related to X-linked neuronal migration disorders (e.g., ARX, DCX, FLNA) and DEEs associated with recently recognized genes (e.g., SLC9A6, SLC35A2, SYN1, ARHGEF9, ATP6AP2, IQSEC2, NEXMIF, PIGA, ALG13, FGF13, GRIA3, SMC1A). It is often difficult to suspect an X-linked mode of transmission in an epilepsy syndrome. Indeed, different models of X-linked inheritance and modifying factors, including epigenetic regulation and X-chromosome inactivation in females, may further complicate genotype-phenotype correlations. The purpose of this work is to provide an extensive and updated narrative review of X-linked epilepsies. This review could support clinicians in the genetic diagnosis and treatment of patients with epilepsy featuring X-linked inheritance.

Multiple cranial neuropathy due to varicella zoster virus reactivation without vesicular rash: a challenging diagnosis.

Ramsay Hunt syndrome is due to reactivation of varicella zoster virus (VZV) dormant in the geniculate ganglion of the facial nerve. The diagnosis is typically based on clinical triad of ipsilateral facial paralysis, otalgia, and vesicles in the auditory canal or the auricle. However, Ramsay Hunt syndrome may occur without skin eruption in up to one third of patients. Moreover, the involvement of other cranial nerves in addition to the facial nerve has been also reported. Herein, we reported a case report of a man who developed a multiple cranial neuropathy caused by VZV reactivation without skin vesicular eruption. The present case underlines a possible diagnostic challenge that clinicians may hit when facing a common disorder such as peripheral facial palsy. Indeed, clinicians must be aware that Ramsay Hunt syndrome may develop without skin vesicular eruption as well it may be complicated by multiple cranial nerve involvement. Antiviral therapy is effective in VZV reactivation for recovery of nerve function.