From splitting GLUT1 deficiency syndromes to overlapping phenotypes.

Introduction: Glucose transporter type 1 deficiency syndrome (GLUT1DS) is a rare genetic disorder due to mutations or deletions in SLC2A1, resulting in impaired glucose uptake through the blood brain barrier. The classic phenotype includes pharmacoresistant epilepsy, intellectual deficiency, microcephaly and complex movement disorders, with hypoglycorrhachia, but milder phenotypes have been described (carbohydrate-responsive phenotype, dystonia and ataxia without epilepsy, paroxysmal exertion-induced dystonia). The aim of our study was to provide a comprehensive overview of GLUT1DS in a French cohort.

GRID2 mutations span from congenital to mild adult-onset cerebellar ataxia.

Objectives: In a large family of Algerian origin, we aimed to identify the genetic mutation segregating with simultaneous presence of adult-onset, paucisymptomatic, slowly progressive, cerebellar ataxia in 7 adults and congenital ataxia in 1 child, and then to assess the involvement of GRID2 mutations in 144 patients with congenital cerebellar ataxia.

Methods: We used a combined approach of linkage analysis and whole-exome sequencing in one family, and a targeted gene panel sequencing approach in 144 congenital ataxias.

Results: In the large family with spinocerebellar ataxia, we identified a missense mutation (c.

[Failure to thrive and psychomotor regression revealing vitamin B12 deficiency in 3 infants].

The newborn's vitamin B12 storage exclusively comes from placenta transfer, later from animal food. We relate 3 observations of infants (3-11-13 months) with failure to thrive, anorexia, vomiting and for the two olders refusal of weaning, associated with psychomotricity regression and hypotony. Blood cell count showed a macrocytosis without anemia (case 2-3) and a severe microcytic anemia for the first case caused by a mild alpha-thalassemia, with megaloblastic bone marrow.

Epsilon sarcoglycan mutations and phenotype in French patients with myoclonic syndromes.

Background: Myoclonus dystonia syndrome (MDS) is an autosomal dominant movement disorder caused by mutations in the epsilon-sarcoglycan gene (SGCE) on chromosome 7q21.

Methods: We have screened for SGCE mutations in index cases from 76 French patients with myoclonic syndromes, including myoclonus dystonia (M-D), essential myoclonus (E-M), primary myoclonic dystonia, generalised dystonia, dystonia with tremor, and benign hereditary chorea. All coding exons of the SGCE gene were analysed.