EEG features and epilepsy in MECP2-mutated patients with the Zappella variant of Rett syndrome.
OBJECTIVE
To assess the presence/absence of peculiar EEG features and epilepsy in MECP2-mutated Rett patients with the Zappella-Rett variant (Z-RTT) also known as preserved speech variant.


METHODS
Retrospective analysis of 16 (age 19.4+/-8.4years; range 8-38years) MECP2 mutated Z-RTT cases, including 11 high or intermediate performance (HIP), and five low-performance (LP) patients was performed. Peculiar EEG features were analyzed as a function of the HIP or LP Z-RTT categories: (1) centro-temporal spikes, (2) multifocal EEG activity, (3) EEG encephalopathy (i.e. multifocal EEG activity associated with the presence of background slowing and diffuse slow activity), (4) spindles and K-complex. Furthermore, we assessed the occurrence of epilepsy. Correlations between electroclinical features and category of Z-RTT genotype (missense or truncation mutation) were also tested.


RESULTS
The Z-RTT HIP group showed a very abnormal EEG (presence of centro-temporal spikes: p=0.004808), although the cases studied were not epileptogenic and did not develop encephalopathy. The LP group showed multifocal EEG activity (p=0.000229), EEG encephalopathy (p=0.000229) and epilepsy (p=0.299451). No significant differences between the prevalence of centro-temporal spikes, multifocal EEG activity, EEG encephalopathy, and epilepsy between the patients with the truncation or missense mutation were observed.


CONCLUSIONS
EEG electrophysiological patterns and epileptogenic susceptibility differ in Z-RTT according to the level of performance (i.e. HIP or LP).


CONCLUSIONS
These results indicate that HIP and LP Z-RTT should be considered as distinct entities, not only on a clinical basis, but also as it concerns EEG features and epileptogenic susceptibility. These results could offer support in the practical management of patients and family counseling.
Buoni
Sabrina
S
Department of Pediatrics, Obstetrics and Reproductive Medicine, Section of Child Neurology and Psychiatry Pediatrics, Azienda Ospedaliera Universitaria Senese, S. Maria alle Scotte Hospital, Siena, Italy. sabrinabuoni@clicsi.net
Zannolli
Raffaella
R
De Felice
Claudio
C
De Nicola
Anna
A
Guerri
Vanessa
V
Guerra
Beatrice
B
Casali
Stefania
S
Pucci
Barbara
B
Corbini
Letizia
L
Mari
Francesca
F
Renieri
Alessandra
A
Zappella
Michele
M
Hayek
Joseph
J
D000293:Adolescent; D000328:Adult; D002648:Child; D004198:Disease Susceptibility; D004569:Electroencephalography; D004827:Epilepsy / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D051783:Methyl-CpG-Binding Protein 2 / Q000235:genetics*; D009154:Mutation; D020125:Mutation, Missense; D012189:Retrospective Studies; D015518:Rett Syndrome / Q000150:complications* / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology; D012720:Severity of Illness Index; D013060:Speech; D055815:Young Adult
D051783:Methyl-CpG-Binding Protein 2