[PCDH19 gene mutations lead to epilepsy with mental retardation limited to females in 2 cases and literature review]

Abstract

Epilepsy with mental retardation limited to females (EFMR) is a syndrome characterized by early onset heat-sensitive epilepsy of infancy or early childhood and generally limited to females, which previously reported that the cadherin gene superfamily subtype protocadherin 19 (PCDH19) gene is its pathogenic gene. We retrospectively analyzed the clinical data for 2 cases of EFMR patients with PCDH19 mutation diagnosed by Department of Pediatric Neurology of Xiangya Hospital, Central South University in 2015. Literature on PubMed, OMIM and HGMD relevant to this syndrome was reviewed, and the clinical characteristics were summarized accordingly. The 2 cases are consistent with the typical clinical manifestations of EFMR caused by PCDH19 mutations. Their seizures are heat sensitive, with or without screaming, and expressed in various forms. Cognitive impairment or autism-like performance were often identified in these patients, hematuria metabolic diseases screening was normal, no abnormal MRI imaging of the head, and de novo PCDH19 gene mutations were found in their epilepsy gene chip sequencing. It is noteworthy that this disease is very similar to the clinical manifestations of the Dravet syndrome due to the mutations of the neurotype sodium channel α1 subunit SCN1A. Therefore, in female patients whose clinical manifestations resemble to Dravet syndrome but SCN1A gene test were negative, EFMR with PCDH19 mutation should be taken into consideration. Early PCDH19 gene testingis of great significance because it not only helps clinicians to understand and analyze the prognosis of this disease, but also offers genetic counseling to the parents.