Monogenic developmental and epileptic encephalopathies of infancy and childhood, a population cohort from Norway.

Introduction: Developmental and epileptic encephalopathies (DEE) is a group of epilepsies where the epileptic activity, seizures and the underlying neurobiology contributes to cognitive and behavioral impairments. Uncovering the causes of DEE is important in order to develop guidelines for treatment and follow-up. The aim of the present study was to describe the clinical picture and to identify genetic causes in a patient cohort with DEE without known etiology, from a Norwegian regional hospital.

Leukoencephalopathy with accumulated succinate is indicative of SDHAF1 related complex II deficiency.

Background: Deficiency of complex II (succinate dehydrogenase, SDH) represents a rare cause of mitochondrial disease and is associated with a wide range of clinical symptoms. Recently, mutations of SDHAF1, the gene encoding for the SDH assembly factor 1, were reported in SDH-defective infantile leukoencephalopathy. Our goal was to identify SDHAF1 mutations in further patients and to delineate the clinical phenotype.

Two brothers with a microduplication including the MECP2 gene: rapid head growth in infancy and resolution of susceptibility to infection.

Microduplications in chromosome Xq28, which include the methyl-CPG binding protein (MECP2) gene, cause severe X-linked mental retardation. Serious recurrent infections are a feature of this condition. Affected males are micro or normocephalic.

Succinate in dystrophic white matter: a proton magnetic resonance spectroscopy finding characteristic for complex II deficiency.

A deficiency of succinate dehydrogenase is a rare cause of mitochondrial encephalomyopathy. Three patients, 2 sisters and 1 boy from an unrelated family, presented with symptoms and magnetic resonance imaging signs of leukoencephalopathy. Localized proton magnetic resonance spectroscopy indicated a prominent singlet at 2.