PRRT2 is mutated in familial and non-familial benign infantile seizures.
BACKGROUND
Mutations of protein-rich transmembrane protein 2 (PRRT2) were recently associated to benign familial infantile seizures (BFIS) (MIM 605751) and paroxysmal kinesigenic dyskinesias (PKD) (MIM12800).


OBJECTIVE
To report mutations of PRRT2 in BFIS, infantile convulsions and choreoathetosis (ICCA), and in sporadic cases affected by benign infantile epilepsy (BIE).


METHODS
A mutational screening of PRRT2 was performed in 5 families, and in 7 sporadic cases affected by BIE. All clinical and neurophysiological details were reviewed.


RESULTS
Thirty-three members among 5 families were collected. Fifteen individuals had infantile seizures and one had infantile seizures followed by paroxysmal kinesigenic dyskinesia (PKD). We found the c.649_650InsC PRRT2 mutation in all tested patients (13 out of 15). Age at onset ranged from 3.5 to 10 months. Focal seizures, with or without secondary generalization, occurred mainly in cluster. One patient at the age of 11 years presented with PKD successfully treated with carbamazepine. All patients had a normal cognitive development. Two out of 7 non-familial cases (28.5%) carried a de novo PRRT2 mutation: the c.649_650InsC mutation in one with clustered seizures at the age of 5 months and an unreported c.718C-T p.R240X mutation in the other who, after cluster focal seizures at the age of 5 months, experienced absences at the age of 5 years.


CONCLUSIONS
Our findings emphasize that PRRT2 mutations might be responsible of both BFIS and ICCA, but might be causative also for sporadic cases of benign infantile seizures. The phenotypic spectrum comprises BFIS, ICCA, and PKD.
Neurology Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, P.zza S. Onofrio 4, 00165 Rome, Italy. nicola.specchio@opbg.net
Nicola
N
Specchio
Alessandra
A
Terracciano
Marina
M
Trivisano
Simona
S
Cappelletti
Dianela
D
Claps
Lorena
L
Travaglini
Raffaella
R
Cusmai
Carlo Efisio
CE
Marras
Federico
F
Zara
Lucia
L
Fusco
Enrico
E
Bertini
Federico
F
Vigevano
D000328:Adult; D017668:Age of Onset; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D004421:Dystonia / Q000235:genetics*; D020936:Epilepsy, Benign Neonatal / Q000235:genetics*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics*; D010375:Pedigree; D012640:Seizures / Q000235:genetics*; D055815:Young Adult
D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C569370:PRRT2 protein, human