Trisomy 12p syndrome: a chromosomal disorder associated with generalized 3-Hz spike and wave discharges.
Three cases (2 boys, 1 girl) of trisomy 12p syndrome are reported. In two, the disorder is caused by a malsegregation of a maternal translocation, the karyotype being 46,XY,der(18),t(12;18)(p11;q23) (case 2) and 46,XX,-10,+ der(10),t(10;12)(p15;p11) (case 3). Case 1 is a de novo case with a regular trisomy 12p in the fibroblasts: 47,XY + (12pter----12 cen. . .?) and a mosaic trisomy 12p in lymphocytes: 46,XY/47,XY, + (12pter----12 cen. . .?). In all cases, the EEG showed 3-Hz generalized spike and wave (SW) discharges. Generalized epilepsy with myoclonic seizures was present in two patients (cases 1 and 2), who may be considered to have a symptomatic generalized epilepsy with a specific etiology. Case 3 has shown only febrile seizures. Any association between the excess of genetic material and the EEG trait "generalized SW" might not be a chance occurrence in this disorder; however, both EEG findings and clinical features (seizure type and frequency) in the 23 cases reported in the literature are too scanty to allow confirmation of such an association.
Centre Saint Paul, Marseille, France.
R
R
Guerrini
M
M
Bureau
M G
MG
Mattei
A
A
Battaglia
M C
MC
Galland
J
J
Roger
D001921:Brain / Q000503:physiopathology*; D002675:Child, Preschool; D002881:Chromosomes, Human, Pair 12; D004569:Electroencephalography; D004827:Epilepsy / Q000235:genetics* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007223:Infant; D007621:Karyotyping; D008297:Male; D003294:Seizures, Febrile / Q000235:genetics* / Q000503:physiopathology; D014314:Trisomy