关键词: 　Dravet综合征；　致病基因；　定位检测；　基因突变

Abstract: Objective　To analyze the genetic characteristics of Dravet syndrome in children in Hainan Province. Methods The peripheral blood of 18 children with Dravet syndrome and their family members in Hainan Province from 2015 to 2017 were collected. The PCR amplification and Sanger sequencing were performed for SCN1A gene detection. The GenomeStudio software was used for the localization and linkage analysis of pathogenic genes. For children who were not found SCN1A gene mutation by Sanger sequencing, the multiple connection dependent probe amplification (MLPA) method was used to analyze the deletion or repetition of the SCN1A gene fragment and to further screen the mutation of the parents' SCN1A gene and analyze the source of the mutation. Results　The results of gene location scan in 18 cases of Dravet syndrome and their parents fully conformed to the Mendel genetic relationship between the parents and children. The children with SCN1A gene mutation could be located in three candidate mutation regions of chromosome 5, 9 and 22. The region of chromosome 5 was located between SNP Rs4957954 and Rs728937; the maximum positive LOD value (2.13) was obtained at Rs1459085. The region of chromosome 9 is located between SNP Rs720974 and Rs1220087, and the maximum positive LOD value (1.92) was obtained at is 1.92 at Rs71332677. The region of chromosome 22 was located between SNP Rs756658 and Rs713751, and the maximum positive LOD value (1.91) was obtained at Rs374225. In the 18 children, SCN1A gene mutation was found in 12 children, among whom 6 children had heterozygous variation (G→A) at the 5383rd base in the CDS region, 4 children had homozygous variation (T→C) at exon 13 and 2292nd base in CDS region, and 2 children had homozygous variation (A→T) in non-coding region of SCN1A gene. Conclusions　The gene localization of the children with Dravet syndrome in Hainan fully conforms to the Mendelian genetic relationship, and it is speculated that Rs4957954 to Rs728937, Rs720974 to Rs1220087, and Rs756658 to Rs713751 are the possible pathogenic regions of Dravet syndrome.

Key words: Dravet syndrome;　pathogenic gene;　location detection;　gene mutation