The ForIPS study (Fig. 1A) included 23 individuals (11 females and 12 males) of which 9 individuals (5 females, 4 males) were healthy controls without any neurologic disease (CT), 14 were patients affected (AP) by one of three neurological diseases: PD (1 female, 8 males), hereditary spastic paraplegia (HSP, SPG11 gene, OMIM #604360 and *610844; 3 females), monogenic intellectual disability (ID; 2 females). The gene discussed is SPG11; the disease is alkaline phosphatase measurement.