Objective To explore the inheritance characteristics of SCN1A gene in familial severe myoclome epilepsy in infancy.Methods The clinical information and blood of the patients and their relatives who had febrile seizure(FS)or epilepsy history were collected.Blood genome DNA were extracted.All exons of SeN1A gene were PCR amplified and screened with denaturing high Performance liquid chromatography(DHPLC)technology,and sequence analysis was performed.Results Fourteen SME patients had FS or epilepsy family history.Five were found positive history in first class relatives and 2 of them had inherited mutations of SCN1A(C.4284+2T>C and e.1216G>T):Other9 were found positive history in second class relatives and 2 of them had de novo mutations of SCN1A.Condusions SCN1A is the pathogenic gene for SME.The same muatation of SCN1A gene can be related to different clinical phenotypes.SME patients whose first class relatives with FS or epilepsy history should be taken as the focus of SCN1A inherited mutation screening.

Objective To study the sodium channel α1-subunit (SCN1A) gene in a pair of monozygotic twins with borderland severe myoclonic epilepsy in infancy (SMEB) and its characteristic of clinical manifestations. Methods The clinical features of 2 monozygotic twins were summarized. All 26 exons of SCNIA genes were screened with denaturing high performance liquid chromatography (DHPLC), and direct sequence analysis was performed on those with abnormal elution peak. Results The proband and her sister showed typical clinical features of SMEB. The same heterozygous mutations on exon 26 which caused the related amino acid change were found among them (c. 5348C > T, A1783E). Conclusion Monozygotic twins with similar clinical phenotype of SMEB have same SCN1A gene mutation.

Objective To study the SCN1A gene in a family with partial epilepsy with febrile seizures plus ( PEFS+ ) and its characteristics of inheritance. Methods The clinical features of the 2 patients and their father were summarized. All 26 exons of SCN1A gene were screened with denaturing high performance liquid chromatography (DHPLC), and direct sequence analysis was pedormed on those with abnormal elution peak. Pyrosequencing was subsequently performed in those without abnormality in direct sequence analysis. Results The proband and his sister had the phenotype of PEFS+ . The same heterozygous mutations (AS768G) on exon 26 which caused the related amino acid change (Q1923R) were found among them. Their father had frequent febrile seizures (FS) in childhood, and seizures stopped spontaneously. No abnormality was found in direct sequence but mosaic mutation in the same site was discovered with pyrosequencing (mutation quantity was 25% ). Conclusions The mutatin of SCN1A could cause partial epilepsy. PEFS+ could be inherited, the relatives carrying the affected gene may have mild clinical symptoms, possibly resulting from the low concentration of the mutated gene due to mosaic mutation.