目的对西藏地区的一个常染色体显性遗传的家族性痉挛性截瘫家系的致病基因进行定位研究。方法用常染色体显性遗传痉挛性截瘫的３个基因区域内的９个微卫星位点：Ｄ１４Ｓ２６４、Ｄ１４Ｓ７５、Ｄ１４Ｓ６９、Ｄ１４Ｓ２６６、Ｄ１４Ｓ６６、Ｄ２Ｓ２３４７、Ｄ２Ｓ２２５５、Ｄ１５Ｓ１２８和ＧＡＢＲＢ３对该家系进行连锁分析。结果各位点最大Ｌｏｄ值分别为：Ｄ１４Ｓ２６４：０．５１６３（θ＝０．０５）；Ｄ１４Ｓ７５：２．１０７２（θ＝０）；Ｄ１４Ｓ６９：０．２８４０（θ＝０．１０）；Ｄ１４Ｓ２６６：０．９３１１（θ＝０）；Ｄ１４Ｓ６６：０．７９９１（θ＝０）；ＧＡＢＲＢ３：０（θ＝０．４０）；Ｄ１５Ｓ１２８：０（θ＝０．４０）；Ｄ２Ｓ２２５５：０（θ＝０．４０）；Ｄ２Ｓ２３４７：０（θ＝０．４０）。结论本家系中的致病基因与ＳＰＧ３基因区域的Ｄ１４Ｓ７５位点连锁（θ＝０，最大Ｌｏｄ值为２．１０）。 Objective To study the pathogenicity of an autosomal dominant familial spastic paraplegia pedigree in Tibet. Methods A total of 9 microsatellite loci (D14S264, D14S75, D14S69, D14S266, D14S66, D2S2347, D2S2255, D15S128 and GABRB3) were sequenced in the three genetic regions of autosomal dominant spastic paraplegia. Results The maximum Lod values ​​at each site were: D14S264: 0.5163 (θ = 0.05); D14S75: 2.1072 (θ = 0); D14S69: 0.2840 (θ = 0.10); D14S266: 0. D15S128: 0 (θ = 0.40); D2S2255: 0 (θ = 0.40); D14S66: 0.7991 (θ = 0); GABRB3: 0 ; D2S2347: 0 (θ = 0.40). Conclusion The causative gene in this family is linked to D14S75 in the SPG3 gene region (θ = 0, maximum Lod value is 2.10).