Current clinical scales that track disease progression are more tailored to spasticity or ataxia, with limited sensitivity to change. The aim was to develop a sensitive and valid scale specifically geared towards optimized sensitivity to change and adapted to patients presenting with both spasticity and ataxia. Longitudinal data from 127 spastic paraplegia type 7 (SPG7) and 112 autosomal recessive spastic ataxia Charlevoix-Saguenay (ARSACS) patients were collected within the multicenter PROSPAX study. Sensitivity to change over 2 years of 30 items from the Scale for the Rating and Assessment of Ataxias (SARA), Spastic Paraplegia Rating Scale (SPRS), and the Activities of Daily Living subscale of the Friedreich's Ataxia Rating Scale (FARS-ADL) was evaluated. Items that demonstrated the highest sensitivity to change were used to build the Spastic Ataxia Composite scale (SPAXCOM). With seven items, the SPAXCOM showed an effect size of 0.71, higher than reference scales (SARA: 0.43, SPRS: 0.42, FARS-ADL: 0.27). The SPAXCOM had a similar sensitivity to change for both genotypes and was more sensitive in participants with a SARA lower than 10 and within the intermediate disease stage (FARS-Disease Staging: 2-3.5). The SPAXCOM showed a high correlation with disease duration (r = 0.67 [0.60; 0.72]) and disease stage (r = 0.86 [0.83; 0.89]). Perception of improvement, stagnation, and worsening were associated with a mean yearly SPAXCOM change of 0.44 (-0.14; 1.01), 0.61 (0.19; 1.03), and 1.22 (0.96; 1.49), respectively. The SPAXCOM is more sensitive to change and homogeneous across genotypes than the reference scales, allowing a reduction of the required sample size in future clinical trials. © 2025 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

With complicated conditions and a large number of potentially causative genes, the diagnosis of a patient with complex inherited peripheral neuropathies (IPNs) is challenging. To provide an overview of the genetic and clinical features of 39 families with complex IPNs from central south China and to optimize the molecular diagnosis approach to this group of heterogeneous diseases, a total of 39 index patients from unrelated families were enrolled, and detailed clinical data were collected. TTR Sanger sequencing, hereditary spastic paraplegia (HSP) gene panel, and dynamic mutation detection in spinocerebellar ataxia (SCAs) were performed according to the respective additional clinical features. Whole-exome sequencing (WES) was used in patients with negative or unclear results. Dynamic mutation detection in NOTCH2NLC and RCF1 was applied as a supplement to WES. As a result, an overall molecular diagnosis rate of 89.7% was achieved. All 21 patients with predominant autonomic dysfunction and multiple organ system involvement carried pathogenic variants in TTR, among which nine had c.349G > T (p.A97S) hotspot variants. Five out of 7 patients (71.4%) with muscle involvement harbored biallelic pathogenic variants in GNE. Five out of 6 patients (83.3%) with spasticity reached definite genetic causes in SACS, KIF5A, BSCL2, and KIAA0196, respectively. NOTCH2NLC GGC repeat expansions were identified in all three cases accompanied by chronic coughing and in one patient accompanied by cognitive impairment. The pathogenic variants, p.F284S and p.G111R in GNE, and p.K4326E in SACS, were first reported. In conclusion, transthyretin amyloidosis with polyneuropathy (ATTR-PN), GNE myopathy, and neuronal intranuclear inclusion disease (NIID) were the most common genotypes in this cohort of complex IPNs. NOTCH2NLC dynamic mutation testing should be added to the molecular diagnostic workflow. We expanded the genetic and related clinical spectrum of GNE myopathy and ARSACS by reporting novel variants.

Hereditary spastic paraplegia is a genetic neurological disorder characterized by spasticity of the lower limbs, and spastic paraplegia type 28 is one of its subtypes. Spastic paraplegia type 28 is a hereditary neurogenerative disorder with an autosomal recessive inheritance caused by loss of function of DDHD1. DDHD1 encodes phospholipase A1, which catalyzes phospholipids to lysophospholipids such as phosphatidic acids and phosphatidylinositols to lysophosphatidic acids and lysophoshatidylinositols. Quantitative changes in these phospholipids can be key to the pathogenesis of SPG28, even at subclinical levels. By lipidome analysis using plasma from mice, we globally examined phospholipids to identify molecules showing significant quantitative changes in Ddhd1 knockout mice. We then examined reproducibility of the quantitative changes in human sera including SPG28 patients. We identified nine kinds of phosphatidylinositols that show significant increases in Ddhd1 knockout mice. Of these, four kinds of phosphatidylinositols replicated the highest level in the SPG28 patient serum. All four kinds of phosphatidylinositols contained oleic acid. This observation suggests that the amount of oleic acid-containing PI was affected by loss of function of DDHD1. Our results also propose the possibility of using oleic acid-containing PI as a blood biomarker for SPG28.

Hereditary spastic paraplegias (HSPs) are a group of inherited rare neurologic disorders characterized by length-dependent degeneration of the corticospinal tracts and dorsal columns, whose prominent clinical feature is represented by spastic gait. Spastic paraplegia type 4 (SPG4, SPAST-HSP) is the most common form. We present both clinical and molecular findings of a large cohort of patients, with the aim of (1) defining the clinical spectrum of SPAST-HSP in Italy; (2) describing their molecular features; and (3) assessing genotype-phenotype correlations to identify features associated with worse disability. A cross-sectional retrospective study with molecular and clinical data collected in an anonymized database was performed. A total of 723 Italian patients with SPAST-HSP (58% men) from 316 families, with a median age at onset of 35 years, were included. Penetrance was 97.8%, with men showing higher Spastic Paraplegia Rating Scale (SPRS) scores (19.67 ± 12.58 vs 16.15 ± 12.61, p = 0.009). In 26.6% of patients with SPAST-HSP, we observed a complicated phenotype, mainly including intellectual disability (8%), polyneuropathy (6.7%), and cognitive decline (6.5%). Late-onset cases seemed to progress more rapidly, and patients with a longer disease course displayed a more severe neurologic disability, with higher SPATAX (3.61 ± 1.46 vs 2.71 ± 1.20, p < 0.001) and SPRS scores (22.63 ± 11.81 vs 12.40 ± 8.83, p < 0.001). Overall, 186 different variants in the SPAST gene were recorded, of which 48 were novel. Patients with SPAST-HSP harboring missense variants displayed intellectual disability (14.5% vs 4.4%, p < 0.001) more frequently, whereas patients with truncating variants presented more commonly cognitive decline (9.7% vs 2.6%, p = 0.001), cerebral atrophy (11.2% vs 3.4%, p = 0.003), lower limb spasticity (61.5% vs 44.5%), urinary symptoms (50.0% vs 31.3%, p < 0.001), and sensorimotor polyneuropathy (11.1% vs 1.1%, p < 0.001). Increasing disease duration (DD) and abnormal motor evoked potentials (MEPs) were also associated with increased likelihood of worse disability (SPATAX score>3). The SPAST-HSP phenotypic spectrum in Italian patients confirms a predominantly pure form of HSP with mild-to-moderate disability in 75% of cases, and slight prevalence of men, who appeared more severely affected. Early-onset cases with intellectual disability were more frequent among patients carrying missense SPAST variants, whereas patients with truncating variants showed a more complicated disease. Both longer DD and altered MEPs are associated with worse disability.

Despite recent advances in next-generation sequencing, the underlying etiology of adult-onset leukoencephalopathy has been difficult to elucidate. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a representative hereditary adult-onset leukoencephalopathy associated with vasculopathy. Leukoencephalopathy in spastic paraplegia type 4 (SPG4) is known to be rare, but it might be underestimated because most spastic paraplegia with leukoencephalopathy is rarely considered. We report a case of co-occurring SPG4 and CADASIL. A 61-year-old male presented with sudden visual impairment after a headache. He showed a spastic gait and had a family history with similar symptoms. An SPG4 gene mutation and a pathogenic variant in the NOTCH3 gene were found. This case shows that the diverse and complex clinical manifestations of patients with extensive leukoencephalopathy are related to more than one gene mutation. We also suggest the necessity for relevant genetic tests in the diagnosis of adult-onset leukoencephalopathy.