title: Brain MRI findings in severe myoclonic epilepsy in infancy and genotype-phenotype correlations.
abstract: BACKGROUND
  To determine the occurrence of neuroradiological abnormalities and to perform genotype-phenotype correlations in severe myoclonic epilepsy of infancy (SMEI, Dravet syndrome).
  
  
  METHODS
  Alpha-subunit type A of voltage-gated sodium channel (SCN1A) mutational screening was performed by denaturing high-performance liquid chromatography (DHPLC) and multiplex ligation probe amplification (MLPA). MRI inclusion criteria were: last examination obtained after the age of 4 years on 1.5-T systems; hippocampal cuts acquired perpendicular to the long axis of the hippocampus; qualitative assessment was performed on T(1)-weighted, T(2)-weighted, proton density, and 1-3 mm thick coronal FLAIR images.
  
  
  RESULTS
  We collected 58 SMEI patients in whom last MRI was performed at or later than 4 years of age. SCN1A mutations occurred in 35 (60%) cases. Thirteen (22.4%) out of 58 patients showed abnormal MRIs. Eight patients showed cortical brain atrophy of which 3 associated to ventricles abnormalities, 1 to cerebellar atrophy, 1 to white matter hyperintensity; 3 patients had ventricles enlargement only; 1 patient showed hippocampal sclerosis (HS); 1 had focal cortical dysplasia. Genotype-phenotype analysis indicated that abnormal MRIs occurred more frequently in patients without SCN1A mutations (9/23; 39.1%) compared to those carrying SCN1A mutations (4/35; 11.4%) (p=0.02).
  
  
  CONCLUSIONS
  Different brain abnormalities may occur in SMEI. Only one case with HS was observed; thus, our study does not support the association between prolonged febrile seizures and HS in SMEI. Abnormal MRIs were significantly more frequent in patients without SCN1A mutations. Prospective MRI studies will assess the etiological role of the changes observed in these patients.
authors: Muscular and Neurodegenerative Disease Unit, Institute G. Gaslini, University of Genova, Italy. pstriano@email.it
authors: Pasquale
authors: P
authors: Striano
authors: Maria Margherita
authors: MM
authors: Mancardi
authors: Roberta
authors: R
authors: Biancheri
authors: Francesca
authors: F
authors: Madia
authors: Elena
authors: E
authors: Gennaro
authors: Roberta
authors: R
authors: Paravidino
authors: Francesca
authors: F
authors: Beccaria
authors: Giuseppe
authors: G
authors: Capovilla
authors: Bernardo
authors: B
authors: Dalla Bernardina
authors: Francesca
authors: F
authors: Darra
authors: Maurizio
authors: M
authors: Elia
authors: Lucio
authors: L
authors: Giordano
authors: Giuseppe
authors: G
authors: Gobbi
authors: Tiziana
authors: T
authors: Granata
authors: Francesca
authors: F
authors: Ragona
authors: Renzo
authors: R
authors: Guerrini
authors: Carla
authors: C
authors: Marini
authors: Davide
authors: D
authors: Mei
authors: Francesca
authors: F
authors: Longaretti
authors: Antonino
authors: A
authors: Romeo
authors: Laura
authors: L
authors: Siri
authors: Nicola
authors: N
authors: Specchio
authors: Federico
authors: F
authors: Vigevano
authors: Salvatore
authors: S
authors: Striano
authors: Fabio
authors: F
authors: Tortora
authors: Andrea
authors: A
authors: Rossi
authors: Carlo
authors: C
authors: Minetti
authors: Charlotte
authors: C
authors: Dravet
authors: Roberto
authors: R
authors: Gaggero
authors: Federico
authors: F
authors: Zara
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D004831:Epilepsies, Myoclonic / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology*; D005260:Female; D005838:Genotype; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D009154:Mutation / Q000235:genetics; D062550:NAV1.1 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins / Q000235:genetics; D010641:Phenotype; D012189:Retrospective Studies; D012720:Severity of Illness Index; D015222:Sodium Channels / Q000235:genetics*; D013577:Syndrome
chemical_list: D062550:NAV1.1 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins; C568242:SCN1A protein, human; D015222:Sodium Channels