Novel POLG1 mutations associated with neuromuscular and liver phenotypes in adults and children.

BACKGROUND: The POLG1 gene encodes the catalytic subunit of DNA polymerase gamma, essential for mitochondrial DNA replication and repair. Mutations in POLG1 have been linked to a spectrum of clinical phenotypes, and may account for up to 25% of all adult presentations of mitochondrial disease. METHODS AND RESULTS: We present 14 patients, with characteristic features of mitochondrial disease including progressive external ophthalmoplegia (PEO) and Alpers-Huttenlocher syndrome and laboratory findings indicative of mitochondrial dysfunction, including cytochrome c oxidase (COX) deficiency and multiple deletions or depletion of the mitochondrial DNA. Four novel POLG1 missense substitutions (p.R597W, p.L605R, p.G746S, p.A862T), are described, together with the first adult patient with a recently described polymerase domain mutation (p.R1047W). All novel changes were rare in a control population and affected highly conserved amino acids. CONCLUSION: The addition of these substitutions-including the first report of a dinucleotide mutation (c.1814_1815TT>GC)-to the growing list of defects further confirms the importance of POLG1 mutations as the underlying abnormality in a range of neurological presentations.

Crossed cerebellar diaschisis secondary to refractory frontal seizures in childhood.

We report a girl with refractory partial seizures since 7 years of age, secondary to right frontal cortical dysplasia, who developed MRI and SPECT abnormalities in the contralateral hemicerebellar cortex. These became more marked, leading to left hemicerebellar atrophy. Crossed cerebellar diaschisis has been described mostly in hemispheric stroke and supratentorial tumours, but less often in epilepsy. It is usually a transient phenomenon. This report shows that crossed cerebellar diaschisis can develop within two years of seizure onset and evolve over time.

Oral ketamine in paediatric non-convulsive status epilepticus.

In children, non-convulsive status epilepticus (NCSE) is rare and difficult to treat. Response to steroids and GABAergic medication is variable and often decreases with increasing duration of NCSE. We present our experience with oral ketamine, an NMDA-receptor antagonist, administered to five children with severe epilepsy (Lennox-Gastaut Syndrome, myoclonic-astatic epilepsy, progressive myoclonic epilepsy and Pseudo-Lennox Syndrome) during an episode of NCSE. Resolution of NCSE was documented in all cases clinically and electroencephalographically within 24-48 hours of starting ketamine. No significant side effects were noted.

[Chronic subdural hematoma and extramedullary erythropoiesis in an infant]. / Cellules érythropoïétiques et hématome sous-dural chronique chez un nourrisson.

We report the case of a six-month old child with bilateral chronic subdural hematoma of unknown origin containing erythroblasts, metamyelocytes and blast-like cells. No such cells were found in venous blood. No primary neoplastic disorder was found. Throughout a 19-month follow-up period, general and neurodevelopmental examination remained normal with complete resolution of the subdural haematoma in the presence of macrocephaly. We discuss the origin and role of these cells.