[The effectiveness of lamotrigine in a case of ring chromosome 14 with refractory epilepsy]

A 25-month old boy was admitted to our hospital due to intractable seizures and developmental retardation. At birth, the patient's head circumference was within normal limits and development appeared normal until approximately six months of age, when symptoms of mental and motor retardation, and microcephaly, gradually appeared. From three months of age, refractory complex partial seizures, secondary generalization of partial seizures, and convulsive status epilepticus occurred. Electroencephalograms (EEGs) taken prior to the patient's referral to our hospital displayed focal spikes at the right occipital region, and at 25 months of age, EEGs showed focal fast activity in the same region. Abnormalities were not detected in the patient's MRI and there was no congenital malformation. Chromosome analysis (G-banding) revealed 46, XY, r (14) (p13q32.3) [28]/45, XY, -14 [2], mosaic ring chromosome 14, and monosomy 14. Clinical experience has shown that even in the absence of malformations, children with developmental delay and refractory seizures may have chromosomal abnormalities, and this was true for our patient. Although consistent clinical characteristics of ring chromosome 14 have not yet been described, the refractory partial seizures that began in early infancy, and the gradual appearance of developmental delay with acquired microcephaly exhibited by our patient are characteristic. However, the patient's refractory seizures have been completely suppressed through an add-on therapy consisting of a relatively low dose of lamotrigine (0.7 mg/kg/day), despite the likely aggravating effect of topiramate.