The distinct manifestation of young-onset amyotrophic lateral sclerosis in China

The burden of upper motor neuron involvement is correlated with the bilateral limb involvement interval in patients with amyotrophic lateral sclerosis: a retrospective observational study

JOURNAL/nrgr/04.03/01300535-202505000-00032/figure1/v/2024-07-28T173839Z/r/image-tiff Amyotrophic lateral sclerosis is a rare neurodegenerative disease characterized by the involvement of both upper and lower motor neurons. Early bilateral limb involvement significantly affects patients' daily lives and may lead them to be confined to bed. However, the effect of upper and lower motor neuron impairment and other risk factors on bilateral limb involvement is unclear. To address this issue, we retrospectively collected data from 586 amyotrophic lateral sclerosis patients with limb onset diagnosed at Peking University Third Hospital between January 2020 and May 2022. A univariate analysis revealed no significant differences in the time intervals of spread in different directions between individuals with upper motor neuron-dominant amyotrophic lateral sclerosis and those with classic amyotrophic lateral sclerosis. We used causal directed acyclic graphs for risk factor determination and Cox proportional hazards models to investigate the association between the duration of bilateral limb involvement and clinical baseline characteristics in amyotrophic lateral sclerosis patients. Multiple factor analyses revealed that higher upper motor neuron scores (hazard ratio [HR] = 1.05, 95% confidence interval [CI] = 1.01-1.09, P = 0.018), onset in the left limb (HR = 0.72, 95% CI = 0.58-0.89, P = 0.002), and a horizontal pattern of progression (HR = 0.46, 95% CI = 0.37-0.58, P < 0.001) were risk factors for a shorter interval until bilateral limb involvement. The results demonstrated that a greater degree of upper motor neuron involvement might cause contralateral limb involvement to progress more quickly in limb-onset amyotrophic lateral sclerosis patients. These findings may improve the management of amyotrophic lateral sclerosis patients with limb onset and the prediction of patient prognosis.

Genetic and in silico analysis of Indian sporadic young onset patient with amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is an old onset devastating neurodegenerative disorder. Young-onset ALS cases especially sporadic ones who are between 25 and 45 years are rarely affected by the disease. Despite the identification of numerous candidate genes associated with ALS, the etiology of the disease remains elusive due to extreme genetic and phenotypic variability. The advent of affordable whole exome sequencing (WES) has opened new avenues for unraveling the disease's pathophysiology better.

METHODS AND RESULTS

We aimed to determine the genetic basis of an Indian-origin, young onset sporadic ALS patient with very rapid deterioration of the disease course without any cognitive decline who was screened for mutations in major ALS candidate genes by WES. Variants detected were reconfirmed by Sanger sequencing. The clinicopathological features were investigated and two heterozygous missense variants were identified: R452W, not previously associated with ALS, present in one of the four conserved C terminal domains in ANXA11 and R208W in SIGMAR1, respectively. Both of these variants were predicted to be damaging by pathogenicity prediction tools and various in silico methods.

CONCLUSION

Our study revealed two potentially pathogenic variants in two ALS candidate genes. The genetic makeup of ALS patients from India has been the subject of a few prior studies, but none of them examined ANXA11 and SIGMAR1 genes so far. These results establish the framework for additional research into the pathogenic processes behind these variations that result in sporadic ALS disease and further our understanding of the genetic makeup of Indian ALS patients.

Identification of TARDBP Gly298Ser as a founder mutation for amyotrophic lateral sclerosis in Southern China

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by predominant impairment of upper and lower motor neurons. Over 50 TARDBP mutations have been reported in both familial (FALS) and sporadic ALS (SALS). Some mutations in TARDBP, e.g. A382T and G294V, have genetic founder effects in certain geographic regions. However, such prevalence and founder effect have not been reported in Chinese.

METHODS

Whole-exome sequencing (WES) was performed in 16 Chinese FALS patients, followed by Sanger sequencing for the TARDBP p.Gly298Ser mutation (G298S) in 798 SALS patients and 1,325 controls. Haplotype analysis using microsatellites flanking TARDBP was conducted in the G298S-carrying patients and noncarriers. The geographic distribution and phenotypic correlation of the TARDBP mutations reported worldwide were reviewed.

RESULTS

WES detected the TARDBP G298S mutation in 8 FALS patients, and Sanger sequencing found additional 8 SALS cases, but no controls, carrying this mutation. All the 16 cases came from Southern China, and 7 of these patients shared the 117-286-257-145-246-270 allele for the D1S2736-D1S1151-D1S2667-D1S489-D1S434-D1S2697 markers, which was not found in the 92 non-carrier patients (0/92) (p < 0.0001) and 65 age-matched and neurologically normal individuals (0/65) (p < 0.0001). The A382T and G298S mutations were prevalent in Europeans and Eastern Asians, respectively. Additionally, carriers for the M337V mutation are dominated by bulbar onset with a long survival, whereas those for G298S are dominated by limb onset with a short survival.

CONCLUSIONS

Some prevalent TARDBP mutations are distributed in a geographic pattern and related to clinical profiles. TARDBP G298S mutation is a founder mutation in the Southern Chinese ALS population.

Genotype-phenotype association of TARDBP mutations in Chinese patients with amyotrophic lateral sclerosis: a single-center study and systematic review of published literature

BACKGROUND

This study aims to determine the genetic and clinical features of TARDBP-mutated patients in our cohort of Chinese patients with amyotrophic lateral sclerosis (ALS) combined with data in the literature.

METHODS

We performed TARDBP mutation screening in 1258 Chinese ALS patients, including 1204 sporadic ALS (sALS) and 54 familial ALS (fALS) patients. A systematic literature review was conducted by searching TARDBP-mutated patients from China in the online databases.

RESULTS

In our cohort, the mutant frequency of TARDBP variants was 0.3% (4/1258), with two recurrent variants (p.G294V, p.G298V) and one novel variant (p.S332G) identified. Combining with data in the literature review, the TARDBP-mutant frequency in the Chinese population was 1.4% (83/5998), with 0.8% (46/5470) in sALS and 7.0% (37/528) in fALS. Most patients had limb onset (63.0%), with an average life expectancy of 4.3 years (range 0.5-13). Disease durations significantly differed (p = 0.002), with p.M337V showing the longest duration (80 months) and p.N378D showing the shortest duration (16.7 months).

CONCLUSION

Our study found that TARDBP mutation was not rare in Chinese fALS patients. Different TARDBP mutations were associated with specific features in phenotypes.

Genetic and clinical features of Chinese sporadic amyotrophic lateral sclerosis patients with TARDBP mutations

OBJECTIVES

To investigate the genetic and clinical features of Chinese sporadic amyotrophic lateral sclerosis (SALS) patients with TARDBP mutations, we carried out a genetic analysis in a cohort of 391 SALS patients and explored the clinical manifestations of patients with TARDBP variants.

MATERIALS AND METHODS

The coding region of all five coding exons of TARDBP, exons 2-6, were sequenced for mutations in 391 Chinese SALS patients. The clinical features of patients with TARDBP mutations were described and compared with cases in literatures.

RESULTS

Two missense mutations in TARDBP gene, c.1132A > G (p.N378D) and c.1147A > G (p.I383V), were detected in three cases, showing a low frequency (0.77%, 3/391) of TARDBP missense mutations in Chinese SALS patients. Based on a retrospective analysis of literatures, p.N378D mutation mainly presents a phenotype of early onset, whereas p.I383V mutation presents pure ALS or ALS alongside semantic variant primary progressive aphasia (svPPA), a type of frontotemporal dementia (FTD).

CONCLUSIONS

Our results demonstrate that TARDBP mutation is a rare cause of Chinese SALS patients and expand the spectrum of phenotype. It is implied that genetic analysis of SALS patients plays a crucial role in uncovering the cause of disease, especially for cases developing early onset or alongside FTD.