Juvenile and adult-onset ALS/MND among Africans: incidence, phenotype, survival: a review

Abstract

Aim: We reviewed the epidemiology of ALS among subjects of African origin, considering incidence, phenotype and prognosis.

Methods: We searched Medline, Scopus, Science direct, Bibliothèque Virtuelle de Neurologie Africaine (BVNA), ( http://www-ient.unilim.fr/ ) and African journal OnLine databases using the following search terms "amyotrophic lateral sclerosis (ALS)", "motor neuron disease (MND)" or "Charcot disease", in combination with "Africa", "ethnic groups", "blacks" or "epidemiology". Of 1264 references examined, 35 were included in this review.

Results and discussion: Among the 35 references, 19 studies were performed in the African continent and dealt with MND/ALS; four other studies focused on ALS-like syndromes; finally, 12 studies were not performed in Africa but focused on either incidence and mortality or survival of ALS in subjects of African origin. Several characteristics of ALS among Africans or subjects of African origin were identified: (i) lower incidence rates among people of African origin living in western countries, (ii) higher incidence of classic ALS among men, (iii) presence of juvenile form, (iv) younger age at onset of classic ALS. We cannot draw firm conclusions about (i) the prognosis in African ALS patients, (ii) prognostic factors, (iii) genetic or behavioral factors affecting incidence or clinical phenotype.

Conclusion: Further multicenter prospective studies with homogeneous methodological approaches need to be performed in Africa to clarify the situation.