Hereditary Spastic Paraparesis

Tight ankle muscles can produce ankle equinus (limited ability to pull the foot upward) and occur often in children, significantly impacting their ability to walk. If not treated, children with ankle equinus frequently experience reduced function and long-term foot problems, such as pain. Currently, treatment options include surgery or Botulinum toxin (BoNTA) injection into the large calf muscles that point the foot downwards, aiming to reduce their tightness. However, these treatments can be less effective over time, can create prolonged calf weakness, and may require long-term bracing. Another small muscle in the leg, the plantaris, is believed to have some contribution to equinus in many children. It is sometimes included in treatment plans for equinus but its contribution is poorly understood. It is unclear whether targeting the plantaris alone could lead to better treatment of ankle equinus. Understanding the effect of treatments targeting the plantaris could help clinicians improve the management of ankle equinus. In this study, the investigators will look at the impact of surgical treatment to the plantaris in ankle equinus. The investigators hypothesize that the plantaris is a significant contributor to equinus. In this study, data will be collected from children undergoing surgical correction of ankle equinus, including lengthening of the plantaris and lengthening of the larger muscles producing equinus (the gastrocsoleus mechanism). Children will be randomly assigned to have either their plantaris or the gastrocsoleus lengthening be done first during surgery. All children will have both structures lengthened during surgery, only the order will be varied and all surgical procedures for each patient will be completed in a single setting. In both groups, maximum passive ankle dorsiflexion (upwards bend of the ankle with the knee straight) will be measured before and after each structure is lengthened. The outcome is maximum passive ankle dorsiflexion (upwards bend of the ankle) with the knee straight. The investigators expect that maximum passive ankle dorsiflexion will increase after lengthening of the plantaris. Understanding the contribution of the plantaris muscle in ankle equinus could lead to significant improvements in the treatment of children with tight ankles.

Safety and Efficacy of AAV9/AP4B1 For Patients with AP4B1-related Hereditary Spastic Paraplegia Type 47 (SPG47): A Phase 1/2 Single-Center, Open-Label Study of Stereotactic Intra-cisterna Magna Administration. The goal of this clinical trial is to evaluate whether a gene therapy can safely treat children with SPG47, a rare genetic condition that causes progressive spasticity and developmental delays. The main questions it aims to answer are: * Is the gene therapy safe and well tolerated? * Does the gene therapy improve motor function and developmental outcomes? Participants will: * Undergo screening assessments to confirm eligibility * Receive a single dose of the gene therapy vector * Attend follow-up visits for safety monitoring and developmental assessments over the course of five years

Hereditary spastic paraparesis is a group of inherited neurological diseases. Only symptomatic treatments exist for the moment. The Modifspa study (cf citation) carried out by the team showed that patients perceived a feeling of effectiveness of physiotherapy on lower limb spasticity. The aim of the Walk-up study is to objectivize this feeling of efficacy on gait disorders in these patients. This is an interventional study using physical training. The study is prospective, open, randomized in 2 parallel groups, one of which is a control group. Analyses will be comparative between the 2 groups during the course of the study.