Spastic paraplegia type 76 (SPG76) is a subtype of hereditary spastic paraplegia (HSP) caused by calpain-1 (CAPN1) mutations. Our study described the phenotypic and genetic characteristics of three families with spastic ataxia due to various CAPN1 mutations and further explored the pathogenesis of the two novel mutations. The three patients were 48, 39, and 48 years old, respectively. Patients 1 and 3 were from consanguineous families, while patient 2 was sporadic. Physical examination showed hypertonia, hyperreflexia, and Babinski signs in the lower limbs. Patients 2 and 3 additionally had dysarthria and depression. CAPN1 mutations were identified by whole-exome sequencing, followed by Sanger sequencing and co-segregation analysis within the family. Functional examination of the newly identified mutations was further explored. Two homozygous mutations were detected in patient 1 (c.213dupG, p.D72Gfs*95) and patient 3 (c.1729+1G>A) with HSP, respectively. Patient 2 had compound heterozygous mutations c.853C>T (p.R285X) and c.1324G>A (p.G442S). Western blotting revealed the p.D72Gfs*95 with a smaller molecular weight than WT and p.G442S. In vitro, the wild-type calpain-1 is mostly located in the cytoplasm and colocalized with tubulin by immunostaining. However, p.D72Gfs*95 and p.G442S abnormally formed intracellular aggregation, with little colocalization with tubulin. In this study, we identified three cases with SPG76, due to four various CAPN1 mutations, presenting lower limb spasticity and ataxia, with or without bulbar involvement and emotional disorder. Among these, c.213dupG and c.1324G>A are first identified in this paper. The genotype-phenotype correlation of the SPG76 cases reported worldwide was further summarized.

To investigate the feasibility and usability of an online spasticity monitoring tool amongst people with hereditary spastic paraplegia or chronic stroke receiving botulinum toxin treatment, and their healthcare providers. Mixed methods cohort study, measuring recruitment success and adherence to the monitoring in 3 rehabilitation institutions. In addition, the System Usability Scale (SUS) and interviews with patients and their healthcare providers were used for quantitative and qualitative analysis, respectively. A deductive directed content analysis was used for qualitative evaluation. Of the 19 persons with hereditary spastic paraplegia and 24 with stroke who enrolled in the study, recruitment success and adherence were higher amongst people with hereditary spastic paraplegia compared with stroke. Usability was found "marginal" by rehabilitation physicians and "good" by patients and physical therapists (SUS scores 69, 76, and 83, respectively). According to all participant groups, online monitoring potentially contributes to spasticity management if it is tailored to the actual needs and capabilities of patients, and if it can easily be integrated into the daily/working routines of all users. Online monitoring of spasticity in people with hereditary spastic paraplegia or stroke receiving treatment with botulinum toxin may be feasible, provided that the monitoring tool is tailored to the needs of all users.

Autosomal recessive hereditary spastic paraplegias (HSP) are a rare group of hereditary neurodegenerative disorders characterized by spasticity with or without other symptoms. SPG11 gene is the most common cause of autosomal recessive HSP. We report a case of autosomal recessive spastic paraplegia type 76 due to heterozygous variants of CAPN1 in an Argentinean subject. A 38-year-old Argentinean female presented with progressive gait problems and instability of 15-year duration. Oculomotor abnormalities, ataxia, bradykinesia, cervical dystonia, and lower limb pyramidal signs were observed. Brain MRI was unremarkable. Whole-exome sequencing analysis identified two heterozygous variants in CAPN1. Clinicians should screen for CAPN1 mutation in a young female patient without significant family history with a spastic paraplegia syndrome associated with other symptoms.

Motor and non-motor manifestations are common and disabling features of hereditary spastic paraplegia (HSP). Botulinum toxin type A (Btx-A) is considered effective for spasticity and may improve gait in these patients. Little is known about the effects of Btx-A on non-motor symptoms in HSP patients. Objective To assess the efficacy of Btx-A on motor and non-motor manifestations in HSP patients. Methods Thirty-three adult patients with a clinical and molecular diagnosis of HSP were evaluated before and after Btx-A injections. Results Mean age was 41.7 ± 13.6 years and there were 18 women. Most patients had a pure phenotype and SPG4 was the most frequent genotype. The Btx-A injections resulted in a decrease in spasticity at the adductor muscles, and no other motor measure was significantly modified. In contrast, fatigue scores were significantly reduced after Btx-A injections. Conclusion Btx-A injections resulted in no significant functional motor improvement for HSP, but fatigue improved after treatment.

Beta-1,4-N-acetyl galactosaminyltransferase 1, B4GALNT1, is a GM2/GD2 synthase, involved in the expression of glycosphingolipids (GSLs) containing sialic acid. Mutations in the gene B4GALNT1 cause Hereditary Spastic Paraplegia 26 (HSP26). In present study we have made attempt to predict the potential structural of the human B4GALNT1 protein. The results illustrated that the amino acid sequences of B4GALNT1 are not 100% conserved among selected twenty species. One signal peptide and one transmembrane domain predicted in human wild type B4GALNT1 protein with aliphatic index of 92.76 and theoretical (iso-electric point) pI of 8.93. It was a kind of unstable protein with Grand average of hydropathicity (GRAVY) of -0.127. Various post-translational modifications were also predicted to exist in B4GALNT1 and predicted to interact with different proteins including ST8SIA5, SLC33A1, GLB1 and others. In the final round, reported missense mutations have shown the further decrease in stability of the protein. This in-silico analysis of B4GALNT1 protein will provide the basis for the further studies on structural variations and biological pathways involving B4GALNT1 in the HSP26.