Expanding the spectrum of C9ORF72-related neurodegenerative disorders in the Greek population

Cognitive deficits in ALS patients with SOD1 mutations

OBJECTIVE

Cognitive decline is common in patients with amyotrophic lateral sclerosis (ALS), especially in carriers of the mutation C9ORF72HRE. However, cognitive impairment is poorly understood in carriers of mutations in other genes causing ALS. We performed a comprehensive neuropsychological testing in patients with mutations in the SOD1 (mSOD1) gene.

METHODS

We examined 5 cognitive domains in 48 symptomatic patients with either hereditary or sporadic ALS. These were compared with 37 matched controls.

RESULTS

Carriers of SOD1-mutations and sporadic ALS had circumscribed deficits, but in a pattern different from C9ORF72HRE. All groups had deficits in working memory, although mSOD1-carriers significantly outperform sporadic ALS and C9ORF72HRE in an attention-driven visuospatial task involving copying a complex figure. Carriers of the D90A-SOD1 mutation overall performed as well as or better than carriers of other SOD1-mutations, except complex working memory. Bayesian analyses suggest (with evidence of moderate strength) that tasks involving the language domain did not differ between controls, mSOD1 and sporadic ALS.

CONCLUSION

Distinct cognitive impairments are prevalent in different ALS-syndromes and vary in patients with different pathogenic SOD1 mutations. The type and degree of impairment differed depending on genotype and was significantly least pronounced in patients homozygous for the D90A SOD1 mutation. The presence of cognitive deficits may influence optimal clinical management and intervention. We propose that cognitive assessment should be included in the routine examination of new patients suspected of ALS. Neuropsychological assessment is an under-recognized outcome parameter in clinical drug trials.

Recent advances in non-Huntington's disease choreas

INTRODUCTION

Chorea is primarily due to an imbalance of basal ganglia output pathways, often due to dysfunction or degeneration of the caudate nucleus and putamen, and can be due to many causes.

METHODS

We reviewed the recent literature to identify newly-recognized causes of chorea, including auto-immune, metabolic, and genetic. We also focused upon developments in mechanisms relating to underlying pathophysiology of certain genetic choreas and advances in therapeutics.

RESULTS

Novel autoantibodies continue to be identified as causes of chorea. Both COVID-19 infection and vaccination are reported to result rarely in chorea, although in some cases causality is not clearly established. Advances in genetic testing continue to find more causes of chorea, and to expand the phenotype of known genetic disorders. Deep brain stimulation can be successful in certain circumstances.

CONCLUSION

Our understanding of mechanisms underlying this movement disorder continues to advance, however much remains to be elucidated.

Young Onset Alzheimer's Disease Associated with C9ORF72 Hexanucleotide Expansion: Further Evidence for a Still Unsolved Association

Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) are recognized as part of a disease continuum (FTD-ALS spectrum), in which the most common genetic cause is chromosome 9 open reading frame 72 (C9ORF72) gene hexanucleotide repeat expansion. The clinical phenotype of patients carrying this expansion varies widely and includes diseases beyond the FTD-ALS spectrum. Although a few cases of patients with C9ORF72 expansion and a clinical or biomarker-supported diagnosis of Alzheimer's disease (AD) have been described, they have been considered too sparse to establish a definite association between the C9ORF72 expansion and AD pathology. Here, we describe a C9ORF72 family with pleomorphic phenotypical expressions: a 54-year-old woman showing cognitive impairment and behavioral disturbances with both neuroimaging and cerebrospinal fluid (CSF) biomarkers consistent with AD pathology, her 49-year-old brother with typical FTD-ALS, and their 63-year-old mother with the behavioral variant of FTD and CSF biomarkers suggestive of AD pathology. The young onset of disease in all three family members and their different phenotypes and biomarker profiles make the simple co-occurrence of different diseases an extremely unlikely explanation. Our report adds to previous findings and may contribute to further expanding the spectrum of diseases associated with C9ORF72 expansion.