An exploration of the genetics of the mutant Huntingtin (mHtt) gene in a cohort of patients with chorea from different ethnic groups in sub-Saharan Africa.

BACKGROUND: Africans are underrepresented in Huntington's disease (HD) research. A European ancestor was postulated to have introduced the mutant Huntingtin (mHtt) gene to the continent; however, recent work has shown the existence of a unique Htt haplotype in South-Africa specific to indigenous Africans. OBJECTIVE: We aimed to investigate the CAG trinucleotide repeats expansion in the Htt gene in a geographically diverse cohort of patients with chorea and unaffected controls from sub-Saharan Africa. METHODS: We evaluated 99 participants: 43 patients with chorea, 21 asymptomatic first-degree relatives of subjects with chorea, and 35 healthy controls for the presence of the mHtt. Participants were recruited from 5 African countries. Additional data were collected from patients positive for the mHtt gene; these included demographics, the presence of psychiatric and (or) cognitive symptoms, family history, spoken languages, and ethnic origin. Additionally, their pedigrees were examined to estimate the number of people at risk of developing HD and to trace back the earliest account of the disease in each region. RESULTS: HD cases were identified in all countries. Overall, 53.4% of patients with chorea were carriers for the mHTT; median tract size was 45 CAG repeats. Of the asymptomatic relatives, 28.6% (6/21) were carriers for the mHTT; median tract size was 40 CAG. No homozygous carries were identified. Median CAG tract size in controls was 17 CAG repeats. Men and women were equally affected by HD. All patients with HD-bar three who were juvenile onset of <21 years-were defined as adult onset (median age of onset was 40 years). HD transmission followed an autosomal dominant pattern in 84.2% (16/19) of HD families. In familial cases, maternal transmission was higher 52.6% (10/19) than paternal transmission 36.8% (7/19). The number of asymptomatic individuals at risk of developing HD was estimated at ten times more than the symptomatic patients. HD could be traced back to the early 1900s in most African sites. HD cases spread over seven ethnic groups belonging to two distinct linguistic lineages separated from each other approximately 54-16 kya ago: Nilo-Sahara and Niger-Congo. CONCLUSION: This is the first study examining HD in multiple sites in sub-Saharan Africa. We demonstrated that HD is found in multiple ethnic groups residing in five sub-Saharan African countries including the first genetically confirmed HD cases from Guinea and Kenya. The prevalence of HD in the African continent, its associated socio-economic impact, and genetic origins need further exploration and reappraisal.

Current clinical presentations of AIDS dementia in a tropical environment: study of 26 observations in the neurology department of the University Hospital of Conakry.

INTRODUCTION: In sub-Saharan Africa (SSA), the clinical and progressive diagnostic certainty of AIDS dementia is difficult to establish due to under-medicalization and delays in consultation and especially the diversity of etiologies of demented states. MATERIAL AND METHODS: We carried out a retrospective study of 196 patients hospitalized for dementia syndrome between 2016 and 2021 in the neurology department of the University Hospital of Conakry. The criteria labeled in this study are those retained by the DSM-IV and the classification of the American Academy of Neurology (AAN) developed in accordance with the WHO. RESULTS: HIV etiology was identified in patients aged 44-67 years (17 women and 19 men). The clinical picture was dominated by severe cognitive disorders, slowed ideation, memory disorders and reduced motor skills associated with personality changes. Neurological examination revealed dysphoric disorders in most patients, sphincter abnormalities in 13 cases and labio-lingual tremor in 11 cases. Diagnosis was based on positive serological tests for HIV1 antibodies (25 cases) and HIV2 antibodies (1 case) using the Elisa and Western blot techniques, and the presence of discretely hypercellular CSF. Magnetic resonance imaging contributed to the diagnosis, showing diffuse white matter abnormalities with hyper signals on T2-weighted or FLAIR sequences. CONCLUSION: This study shows a non-stereotype clinical picture of AIDS dementia requiring a differential diagnosis with other infectious dementias. These results are important for the therapeutic and prognostic discussion.

Post-stroke Chorea in the Neurology Department of Ignace Deen Hospital of Conakry, Guinea.

INTRODUCTION: Chorea is an uncommon complication of stroke. The pathophysiology, the exact location of the lesions, and the evolution of this type of chorea are still poorly understood. The objective was to describe the epidemiological, clinical, and imaging profile of post-stroke chorea in a tropical environment in the context of a stroke epidemic. MATERIAL AND METHODS: We conducted a five-year retrospective observational study from 2015 to 2020 on stroke patients who presented with chorea in our department. Epidemiological, clinical, and imaging data were registered. RESULTS: Fourteen patients presented with chorea after their stroke, a frequency of 0.6%. The average age was 57.1 years with a male predominance. Hypertension was the cardiovascular risk factor in half of the patients; three patients (21.4) were diabetic. Chorea was the initial manifestation of the stroke in eight patients (57.1%). Thirteen patients (92.9%) had an ischaemic stroke and one had a cerebral haemorrhage. The middle cerebral artery (MCA) was involved in nine patients (64.3%), the anterior cerebral artery (ACA) in three patients (21.4%), and two patients (14.3%) had posterior cerebral artery (PCA) involvement. The lesions were cortical in five patients (35.7%), five other patients (35.7%) had a deep location, and four patients (28.6%) had both deep and cortical locations of their lesions. The structures affected were the lentiform nucleus (50%), the insula (35.7%), the caudate nucleus (14.3%), and the thalamus (14.3%). CONCLUSION: Post-stroke chorea is poorly studied in the tropics. In the presence of any acute abnormal movement associated with cardiovascular risk factors, post-stroke chorea should be considered. Recovery is rapid when treated early.

Non-Photochemical Quenching Involved in the Regulation of Photosynthesis of Rice Leaves under High Nitrogen Conditions.

Excess and deficient nitrogen (N) inhibit photosynthesis in the leaves of rice plants, but the underlying mechanism is still unclear. N can improve the chlorophyll content and thus affect photon absorption, but the photosynthetic rate does not increase accordingly. To investigate this mechanism, three concentrations of N treatments were applied to two rice varieties, Zhefu802 and Fgl. The results indicated increased chlorophyll content of leaves with an increased N supply. Little discrepancy was detected in Rubisco enzyme activity and Non-photochemical quenching (NPQ) in the high nitrogen (HN) and moderate nitrogen (MN) treatments. The model that photoinhibition occurs in Zhefu802 due to a lack of balance of light absorption and utilization is supported by the higher malondialdehyde (MDA) content, higher H2O2 content, and photoinhibitory quenching (qI) in HN treatment compared with MN treatment. A lower proportion of N in leaf was used to synthesize chlorophyll for Fgl compared with Zhefu802, reducing the likelihood of photoinhibition under HN treatment. In conclusion, HN supply does not allow ideal photosynthetic rate and increases the likelihood of photoinhibition because it does not sustain the balance of light absorption and utilization. Apart from Rubisco enzyme activity, NPQ mainly contributes to the unbalance. These results of this study will provide reference for the effective N management of rice.

Medullar Kock without Pott: 13 cases observed at the university hospital center of Conakry, Guinea.

Background: The diagnostic certainty of medullar tuberculosis (TB) without Pott disease is difficult to establish in a tropical environment with the large group of infectious, parasitic, and systemic myelopathies, despite the increasing availability of magnetic resonance imaging (MRI) data and improvement of biological exploration platforms. Methods: We retrospectively analyzed the files of 186 patients hospitalized in the Department of Neurology and Neurosurgery of the University Hospital Center of Conakry, Guinea, between 2008 and 2016 for the management of non-compressive and compressive myelopathy. Biological evidence of TB infection was demonstrated for 13 (6.9%) patients. Results: Infectious clinical picture prior to the development of neurological signs was reported in 11 patients (84.6%). The neurological signs were summed up by the existence of a sensitivo-motor semiology of progressive evolution (100% of cases) with sphincter disorders in 11 patients (84.6%) and a medullary compression symptomatology with a lesion and under lesion syndrome from the outset in 4 patients (30.8%). Medullary MRI revealed an extensive intramedullary hypersignal in 9 patients with non-compressive myelopathy and in 4 cases, the lesions appeared in T1 hypersignal and T2 isosignal were localized. Lumbar puncture (LP) revealed lymphocytic pleocytosis, hypoglucorrhage (0.3 to 0.5 g/l), and leukocytosis. Conclusion: This study reveals a classic clinical, biological, neuroradiological, and evolutionary profile of compressive and non-compressive myelopathies. These results are important for the therapeutic and evolutionary discussion of TB myelopathies for good management.