Table 1: Overview of studies into MNDs in Sub-Saharan Africa.

Article referenceCountry and settingStudy design and yearSample characteristicsDiagnostic criteria and tools usedDisease prevalenceDisease risk factors and genetic determinants identified

Wilmshurst et al. [15]South Africa;
Case-controlled studies;
30 patients: 4 SMA type 1 patients; 16 SMA type 2 patients; 10 SMA type 3 patients. All patients were black South Africans. Six horn cell disease patients were used as controlsClinical diagnosisNAHomozygous deletions of exon 7 or exons 7 and 8 of the SMN1 gene in all patients.
Patients were found not to be genetically or phenotypically different from internationally recognised forms of SMA

Ekenze et al. [16] Nigeria; hospital-basedRetrospective; 2003–20078440 patients: 1249 patients (640 men) suffering from neurological disorders (45 y mean age). Ten of these patients were suffering from ALS (4 were men)NA800/100,000NA

Sangaré et al. [17]Mali; hospital-/laboratory-basedCase-controlled studies 628 Malians, 120 Nigerians, and 120 Kenyans (healthy individuals)NA1/209 SMA carrier frequency in the SSA patients (mostly Malians) compared to 1/30–50 in Europeans and AsiansParticipants had 3 or more copy numbers of SMN1 gene and lacked SMN2 compared to Europeans

Osuntokun et al. [18]Nigeria; hospital-basedRetrospective; 1958–197392 patients with MND: 73 ALS, 9 SMA, and 10 PMA ENMG, muscle biopsy21/100,000NA

Stevens et al. [14]South Africa; hospital-basedCase study series29 SMA patientsClinicalNA; the study concluded that differences in SMA
phenotype in black patients may be due to different molecular/genetic basis mediating the disease among such populations
65.5% (19/29) homozygous SMN1 deletions in black patients. 47% (4/29) of SMN1 deletions were found in telomeric exon 7 but not exon 8. Also, 14% homozygous NAIP deletions were identified.
No gene deletions were found in 35% of patients

Adam [19] Kenya; hospital-basedRetrospective; 1978–198847 MND participants (35 men and 12 women). 18 of these were suffering from ALS (13–80 y olds)Clinical, 1/3 ENMG NANA

Kiepiela et al. [20]South Africa;
Case-controlled studies South African and Indian SMA patientsClinicalNAGenetics: no significant changes in patients’ immunoregulatory cells identified

Kengne et al. [21]Cameroon; hospital-basedRetrospective; 1993–20014041 patients; 145 with neurological diseases. Ten out of these were suffering from ALS (8 men and 2 women); mean age = 50.9 yNA250/100,000 of all neurologic consultations; 12% of all neurological cases NA

Imam and Ogunniyi [9]Nigeria; hospital-basedRetrospective; 1980–199916 ALS patients (15 men and 1 woman), 16–60 yEl Escorial diagnostic criteriaNAIdentified risk factor: trauma in 37.5% of subjects

Sene et al. [22] Senegal; hospital-basedRetrospective; 1999-200033 ALS patientsEl Escorial diagnostic criteria, ENMGNANA

Tekle-Haimanot et al. [23] Ethiopia; community-basedCross-sectional; 1986–198860820 participants (29412 men), 59% < 20 y, 3 MND patients (2 men and 1 woman)Neurological examinations, screening questionnaire5/100,000NA

Labrum et al. [13]South Africa; hospital-basedCase-controlled studies 116 SMA patients; 92 of black ancestry, 24 white patientsClinical (not ENMG)Carrier frequency of 1/50 in black population but 1/23 in white population51% homozygous deletions of SMN1 gene in black patients, as opposed to 95% of patients worldwide

Wall and Gelfand [24]Zimbabwe; hospital-basedRetrospective; 1967–197113 MND patients; 24–55 yClinical (not ENMG)NASensory changes in six participants

Lumaka et al. [11]Kinshasha, Congo; hospital-basedCase study1 SMA type 1 infant patientClinical, ENMGNA; family history (similar symptomatology in elder brother)Extreme hypotonia in infancy; homozygous deletions of SMN1; 2 SMN2 alleles present

Collomb et al. [25] Senegal; hospital-basedRetrospective; 1960–196818 ALS patients (17 men and 1 woman), 25–70 yClinical (not ENMG)NANA

Pelleboer et al. [26] Nigeria; hospital-basedCase study1 SMA type 1 infantClinicalNANA

Bauer et al. [27]Tanzania, hospital-basedCase-controlled series;
117 SA inpatient admissions and 117 matched controls; 24–77 yNeurological examination, screening questionnaire7/117 in SA group but 0/117 in control groupSA was identified as a risk factor for muscular atrophy

Ndiaye et al. [28]Senegal; hospital-basedCase study series5 SMA type 1 patientsClinical, ENMGNAIdentified risk factors: severe hypotonia in infancy, family history of SMA

Osuntokun et al. [29]Nigeria; community-basedCross-sectional18954 participants; 9282 men, 58% < 20 y, 11% > 50 yScreening questionnaireMND; 15/100,000NA

Lekoubou et al. [30]SSA; systematic analysis of associations between MNDs and diabetes mellitusRetrospective (3 case control and 2 cross-sectional studies) Up to 2371 ALS cases reviewedNANANo association between ALS and diabetes mellitus identified

Abdulla et al. [31] Sudan; hospital-basedRetrospective; 1993–199528 MND patients, including 19 ALS patientsClinical, ENMGNAFamily history of MND identified in 14% of patients

Cosnett et al. [32] South Africa; hospital-basedRetrospective; reviewed 9.5 y of cases 59 blacks (47.4 y mean age), 9 Indians, 16 whites, 2 coloured patients (54 y mean age for non-black patients)Clinical, 45% ENMGThe following prevalence values per 100,000 persons were observed for different populations: blacks (0.88), whites (), coloured (), Indians (1.4).NA

Harries [33] Ethiopia; hospital-basedCase study series; 19542 male participants, aged 26 and 30 yClinical (no ENMG)NANA

Meilleur et al. [34]Mali; hospital/laboratory-basedCase control Study cohort included 2 spastic paraplegia patients with amyotrophy, 5 extended family members, and 43 unrelated people of the same ethnic groupClinicalNA Extended homozygosity at chromosome 19p13.11-q12 (designated as SPG43) in patients but not controls

Jacquin-Cotton et al. [35] Senegal; hospital-basedRetrospective; 1960–19696100 patients; 18 ALS (16 men), 25–70 yClinical (no ENMG)290/100,000NA

Moosa and Dawood [36]SSACase study series45 SMA patients; 15 SMA type 1, 19 type 2, and 9 type 3; infants to 48 month olds; 1 : 1.7 female/male ratioClinical, ENMGNAFacial weakness in 80% of type 1 patients

Piquemal et al. [37] Ivory Coast; hospital-basedRetrospective; 1971–19804000 patients; 30 ALS (22 men), 50% < 40 yClinical (no ENMG).750/100,000NA

Landouré et al. [38]Mali; hospital- and laboratory-basedCase controlStudy cohort included 2 spastic paraplegia patients with amyotrophy, 298 Malian controls, and several alleles found in the NHLBI exome sequencing Project databaseClinical NAHomozygous missense variation of c.187G>C; p.Ala63Pro, in C19orf12, was observed in the spastic paraplegia patients but not in the 298 Malian control subjects

ALS, amyotrophic lateral sclerosis; ENMG, electroneuromyography; MND, motor neuron disease; NA, not available; PMA, progressive muscular atrophy; SMA, spinal muscular atrophy; y, years; m, months; SA, spinal anaesthesia; SMN1, Survival Motor Neuron 1 gene; NAIP, Neuronal Apoptosis Inhibitory Protein; NHLBI, National Heart, Lung, and Blood Institute.