The hereditary spastic paraplegias (HSP) are a diverse group of inherited disorders of the spinal cord. They may be transmitted dominantly or recessively, and through the X Chromosome. There are, at the last count, 79 different genetic forms of HSP. These are titled, rather confusingly, SPG1 to SPG79.
Some forms of HSP occur more frequently than others. SPG4 is the most common form, accounting for up to 40% of cases. SPG3 follows closely by causing 10% of HSPs. Other frequent forms are SPG1, SPG2, SPG7, SPG11, and SPG12. Some HSPs are so rare they have been reported in only single subjects or families.
The cardinal feature of the HSPs is lower limb stiffness or spasticity. This often produces a characteristic stiff gait which, at its most extreme, causes the legs to cross each other, aptly called scissors gait. Another frequent feature is proprioceptive loss, the inability to tell where the limbs are positioned. This arises from impaired function of the posterior or dorsal collumns of the spinal cord.
Some forms of HSP manifest only with spasticity and are classified as Pure HSP. More often, however, HSP manifests with additional features and is then classified as Complex HSP. Neurochecklists has explored all these aspects of HSP and has created a checklist for each HSP! To make things even easier, we have also produced the following summarising checklists:
- A checklist summarising the key features of the HSPs.
- Checklists for the different clinical and genetic features of HSP
- Checklists of the diverse radiological features of HSP
- Checklists of differential diagnosis of HSP
- Checklists of investigations for HSP
In the process of creating the HSP checklists, Neurochecklists has counted at least 130 different ways HSP manifests. Below is a full alphabetical list, each linked to an HSP that manifests with the feature. Bear in mind however that many HSPs present with the same features. We have placed an asterisk next to the most common HSP manifestations.