A novel SACS p.Pro4154GlnfsTer20 mutation in a family with autosomal recessive spastic ataxia of Charlevoix-Saguenay

Documenting manifestations and impacts of autosomal recessive spastic ataxia of Charlevoix-Saguenay to develop patient-reported outcome

BACKGROUND

Autosomal recessive cerebellar ataxias (ARCA) are a group of rare inherited disorders characterized by degeneration or abnormal development of the cerebellum. Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is one of the most prevalent in Europe.

OBJECTIVES

The aim of this study is to provide a better understanding of the manifestations and impacts of ARSACS.

METHODS

A systematic review of the literature was conducted, followed by a qualitative study using semistructured interviews and discussion groups to obtain the experience of people affected.

RESULTS

According to the PROMIS framework, the results show manifestations and impacts in three components of health: physical, mental, and social. Fatigue and struggles with balance and dexterity are the physical manifestations of the disease most often cited by participants. Negative affects such as frustration and depression are among the mental health impacts with some loss in cognitive abilities. Social health is the least documented component; nonetheless, people with the disease report significant impacts in terms of social relationships, activities and work.

CONCLUSIONS

These findings shed new light on the experience of people with recessive ataxia and identify key aspects to assess to improve their overall health.

Genetics of Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS) and Role of Sacsin in Neurodegeneration

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is an early-onset neurodegenerative disease that was originally discovered in the population from the Charlevoix-Saguenay-Lac-Saint-Jean (CSLSJ) region in Quebec. Although the disease progression of ARSACS may start in early childhood, cases with later onset have also been observed. Spasticity and ataxia could be common phenotypes, and retinal optic nerve hypermyelination is detected in the majority of patients. Other symptoms, such as pes cavus, ataxia and limb deformities, are also frequently observed in affected individuals. More than 200 mutations have been discovered in the SACS gene around the world. Besides French Canadians, SACS genetics have been extensively studied in Tunisia or Japan. Recently, emerging studies discovered SACS mutations in several other countries. SACS mutations could be associated with pathogenicity either in the homozygous or compound heterozygous stages. Sacsin has been confirmed to be involved in chaperon activities, controlling the microtubule balance or cell migration. Additionally, sacsin may also play a crucial role in regulating the mitochondrial functions. Through these mechanisms, it may share common mechanisms with other neurodegenerative diseases. Further studies are needed to define the exact functions of sacsin. This review introduces the genetic mutations discovered in the SACS gene and discusses its pathomechanisms and its possible involvement in other neurodegenerative diseases.