Objective: Describe the clinical and molecular findings in two families originating from Senegal.

Background: Spinocerebellar ataxia type 7 is an inherited neurodegenerative disease caused by a pathogenic expansion of a CAG repeat within the ataxin 7 gene, resulting in an expanded polyglutamine tract in the ATXN7 protein. In Africa, established studies mainly concern populations in South Africa and elsewhere studies are limited to clinical cases.

Method: The patients were followed up in the movement disorders outpatient clinic at the neurology department of “Centre Hospitalier National de Pikine” in Dakar. The blood from the patients were collected by venous puncture. The DNA was extracted from blood samples using by LGC Biosearch Technologies DNA extraction services and stored at -80^oC and SCA1, 2, 3, and 7 were tested.

Results: The first family is a large one in which the case control is a 35-year-old man with no particular personal history, who presented with progressive cerebellar syndrome and vision disorders for 5 to 6 years (video 1). Some members of his family had ataxia also (figure 1).  The SARA score of 12/40. Fundus shows macular degeneration and brain MRI showed cerebello-vermian atrophy (figure 1 A).

The second family is an average family which the control case is a 16-year-old girl who, for the past two years, has presented with cerebellar syndrome (video 2) with a progressive decline in vision as some of her family members (figure 2). The SARA score was 15/40.

Fundus shows bilateral macular and brain MRI showed moderate cerebellar atrophy (figure 2 A). For both families the SCA7 was found (Supplementary Figure 1-A and Supplementary Figure 2-A).

Conclusion: SCA is a common clinical phenotype in sub-Saharan Africa, but is under-reported due to a lack of appropriate facilities. SCA7 is thought to be predominant in Senegal, but this assertion needs to be confirmed by other large-scale cohort studies.

Figure 1 and 2

Figure 1-A

Figure 2-A

Supplementary Figure 1-A

Supplementary Figure 2-A

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MDS Abstracts - https://www.mdsabstracts.org/abstract/spinocerebellar-ataxia-type-7-first-report-of-clinical-and-molecular-findings-of-two-family-in-senegal-west-africa-video-cases/