1、病因及发病机制：基因突变导致蛋白质生成异常、代谢异常、髓鞘脱失、轴索变性等从而改变生理功能，造成病理影响，并随基因传播到下一代。

2、Friedreich 型共济失调主要是常染色体隐性遗传；

脊髓小脑性共济失调包括SCA1-SCA29，SCA9未知，SCA24为常染色体隐形遗传，其余大多为常染色体显性遗传；

 遗传性痉挛性截瘫主要的遗传方式为常染色体显性遗传，常染色体隐形遗传和X连锁隐形遗传少见；

腓骨肌萎缩症主要的遗传方式为常染色体显性遗传。

1. Etiology and pathogenesis: gene mutation leads to abnormal protein production, abnormal metabolism, demyelination, axonal degeneration, etc., so as to change physiological functions, cause pathological effects, and spread to the next generation with the gene.
2. Friedreich ataxia is mainly autosomal recessive inheritance;
Spinocerebellar ataxia includes sca1-sca29, sca9 is unknown, sca24 is autosomal recessive inheritance, and most of the others are autosomal dominant inheritance;
The main genetic mode of hereditary spastic paraplegia is autosomal dominant inheritance, and autosomal recessive inheritance and X-linked recessive inheritance are rare;
The main genetic mode of peroneal muscular atrophy is autosomal dominant inheritance.