SPAST and hereditary spastic paraplegia: As a result, out of 70 families (29%) with HSP there were 5 families with AD SPG30 (7.1% of all verified cases and 11.0% of AD forms) This makes AD SPG30 form the 2nd most frequent SPG form in the overall incidence statistic, that is being surpassed by only SPG4 [15].