The correlation between specific chromosome abnormalties and various epilepsies was investigated by a study of 76 patients’ records obtained by questionnaires distributed to members of Kyoto Multi-institutional Study Group of Pediatric Neurology. Chromosome abnormalities included the following: Down syndrome in 19 patients, Angelman syndrome (8), Prader-Willi syndrome (4), 4p-syndrome (3), and 35 other chromosome syndromes with 1-2 patients each. The severity of mental retardation correlated with the severity of epilepsy. With the exception of Angelman syndrome which showed a relatively good epilepsy prognosis, patients with severe mental retardation had a poor seizure prognosis (P<0.005). The type of seizure disorder showed some correlation with the developmental syndrome: febrile seizures were more frequent in patients with Angelman and Prader-Willi syndromes than with other syndromes (P<0.005), and were often seen with 4p-syndrome (2/3); status epilepticus was also characteristic of 4p-syndrome; West syndrome and focal epilepsy were common in Down syndrome; and partial seizures and a good prognosis of epilepsy were present in Klinefelter syndrome (n=2). The EEG paroxysmal abnormalities in occipital regions and diffuse high voltage slow waves found in Angelman syndrome were characteristic and helpful in diagnosis. 
COMMENT. Febrile seizures are a common feature of chromosome syndromes. In this study, the incidence of febrile seizures was higher in Angelman syndrome (75%, 6/8) and Prader-Willi syndrome (100%, 4/4) than with other chromosome abnormalties (28%, 18/64) or in the general population (3-4%). The authors propose that the deleted region of chromosome 15ql1-13 that is present in both Angelman and Prader-Willi syndromes may be a new locus for febrile seizures and epileptogenesis. The above article is one of a series on chromosomal aberrations and childhood epilepsies published in the same journal and presented at a 2003 annual meeting of the Infantile Seizure Society in Tokyo, organized by Dr Yukio Fukuyama and colleagues.