Hereditary spastic paraplegia (HSP) comprises a large group of neurogenetic disorders characterized by progressive lower extremity spasticity. Neurological evaluation and genetic testing were ...completed in a Malian family with early-onset HSP. Three children with unaffected consanguineous parents presented with symptoms consistent with childhood-onset complicated HSP. Neurological evaluation found lower limb weakness, spasticity, dysarthria, seizures, and intellectual disability. Brain MRI showed corpus callosum thinning with cortical and spinal cord atrophy, and an EEG detected slow background in the index patient. Whole exome sequencing identified a homozygous missense variant in the adaptor protein (AP) complex 2 alpha-2 subunit (AP2A2) gene. Western blot analysis showed reduced levels of AP2A2 in patient-iPSC derived neuronal cells. Endocytosis of transferrin receptor (TfR) was decreased in patient-derived neurons. In addition, we observed increased axon initial segment length in patient-derived neurons. Xenopus tropicalis tadpoles with ap2a2 knockout showed cerebral edema and progressive seizures. Immunoprecipitation of the mutant human AP-2-appendage alpha-C construct showed defective binding to accessory proteins. We report AP2A2 as a novel genetic entity associated with HSP and provide functional data in patient-derived neuron cells and a frog model. These findings expand our understanding of the mechanism of HSP and improve the genetic diagnosis of this condition.
•AP2A2 mutation is a novel genetic entity associated with neurodegenerative disease.•Mutation causes cell type specific defects in adaptor protein levels and function.•Patient derived cortical neurons have alteration of axonal initial segment length.•ap2a2 knockout in Xenopus tropicalis recapitulates seizures detected in patients.
Diabetic polyneuropathy (DPN) with or without neuropathic pain is a frequent complication of diabetes. This work aimed to determine the prevalence of diabetic polyneuropathy, to describe its ...epidemiological aspects, and to analyze the therapeutic itinerary of patients with DPN.
This was a cross-sectional, descriptive study performed synchronously over six months at two major follow-up sites for patients with diabetes in Mali. DPN was diagnosed based on the Michigan Neuropathy Screening Instrument (MNSI). The neuropathic nature of the pain and the quality of life of patients were evaluated by the DN4 and the ED-5D scale, respectively. We used three (3) different questionnaires to collect data from patients (one at inclusion and another during the follow-up consultation) and from the caregivers of patients with DPN.
We included 252 patients with diabetes, and DPN was found to have a healthcare facility-based prevalence of 69.8% (176/252). The sex ratio was approximately three females for every male patient. The patients were mostly 31 to 60 years of age, 83% had type 2 diabetes, and 86.9% had neuropathic pain Approximately half of the patients (48.3%) had autonomic neuropathy and they reported moderate to intense pain, which was mainly described as a burning sensation. The patients exhibited impaired exteroceptive and proprioceptive sensations in 51.7% of cases. The patients smoked tobacco in 3.4% of cases, while 36.6% of the patients were obese and had dyslipidemia. The caregivers clearly indicated that appropriate medications were not readily accessible or available for their patients with DPN.
The healthcare facility-based prevalence of DPN with or without neuropathic pain was high in our cohort. These inexpensive and easy-to-use tools (MNSI, DN4) can be used to adequately diagnose DPN in the African context. In Mali, screening and early treatment of patients at risk of DPN should allow for a reduction of the burden of the disease, while caregivers need to be adequately trained to manage DPN.
Background
Our recent studies have shown headache disorders to be very common in the central and western sub-Saharan countries of Benin and Cameroon. Here we report headache in nearby Mali, a ...strife-torn country that differs topographically, culturally, politically and economically. The purposes were to estimate headache-attributed burden and need for headache care.
Methods
We used cluster-random sampling in seven of Mali’s eleven regions to obtain a nationally representative sample. During unannounced household visits by trained interviewers, one randomly selected adult member (18–65 years) from each household was interviewed using the structured HARDSHIP questionnaire, with enquiries into headache in the last year and, additionally, headache yesterday (HY). Headache on ≥ 15 days/month (H15+) was diagnosed as probable medication-overuse headache (pMOH) when associated with acute medication use on ≥ 15 days/month, and as “other H15+” when not. Episodic headache (on < 15 days/month) was recorded as such and not further diagnosed. Burden was assessed as impaired participation (days lost from paid and household work, and from leisure activity). Need for headache care was defined by criteria for expectation of benefit.
Results
Data collection coincided with the SARS-CoV-2 pandemic. The participating proportion was nonetheless extremely high (99.4%). The observed 1-year prevalence of any headache was 90.9%. Age- and gender-adjusted estimates were 86.3% for episodic headache, 1.4% for pMOH and 3.1% for other H15+. HY was reported by 16.8% with a mean duration of 8.7 h. Overall mean headache frequency was 3.5 days/month. Participants with pMOH lost more days from paid (8.8 days/3 months) and household work (10.3 days/3 months) than those with other H15+ (3.1 and 2.8 days/3 months) or episodic headache (1.2 and 0.9 days/3 months). At population level, 3.6–5.8% of all time was spent with headache, which led to a 3.6% decrease in all activity (impaired participation). Almost a quarter (23.4%) of Mali’s adult population need headache care.
Conclusion
Headache is very common in Mali, as in its near neighbours, Benin and Cameroon, and associated with substantial losses of health and productivity. Need for headache care is high – a challenge for a low-income country – but lost productivity probably translates into lost gross domestic product.
GNE-myopathy (GNE-M) is a rare autosomal recessive disorder caused by variants in the GNE gene. We report a novel variant in GNE causing GNE-M in a Malian family. A 19-year-old male patient from ...consanguineous marriage was seen for progressive walking difficulty. Neurological examination found predominant distal muscle weakness and atrophy, decreased tendon reflexes, predominating in lower limbs. Electroneuromyography showed an axonal neuropathy pattern. However, whole exome sequencing (WES) revealed a novel biallelic variant in GNE c.1838G > A:p.Gly613Glu, segregating with the phenotype within the family. This study highlights its diagnosis challenges in sub-Saharan Africa and broadens the genetic spectrum of this rare disease.GNE-myopathy (GNE-M) is a rare autosomal recessive disorder caused by variants in the GNE gene. We report a novel variant in GNE causing GNE-M in a Malian family. A 19-year-old male patient from consanguineous marriage was seen for progressive walking difficulty. Neurological examination found predominant distal muscle weakness and atrophy, decreased tendon reflexes, predominating in lower limbs. Electroneuromyography showed an axonal neuropathy pattern. However, whole exome sequencing (WES) revealed a novel biallelic variant in GNE c.1838G > A:p.Gly613Glu, segregating with the phenotype within the family. This study highlights its diagnosis challenges in sub-Saharan Africa and broadens the genetic spectrum of this rare disease.
X‐linked Charcot‐Marie‐Tooth type 1 (CMTX1) disease is one of the most common subtypes of inherited neuropathies and is caused by mutations in the GJB1 gene. To date, more than 400 mutations have ...been reported in GJB1 worldwide but none in sub‐Saharan Africa (SSA). We aimed to clinically characterize patients with CMTX1 and identify the genetic defects. All patients were examined thoroughly, and Nerve Conduction Studies (NCS) were done. EEG and pure tone audiometry (PTA) were also done in select individuals having additional symptoms. DNA was extracted for CMT gene panel testing (50 genes + mtDNA and PMP22 duplication), and putative variants were screened in available relatives. The predominant starting symptom was tingling, and the chief complaint was gait difficulty. Neurological examination found a distal muscle weakness and atrophy, and sensory loss, skeletal deformities, decreased or absent reflexes and steppage gait. The inheritance pattern was consistent with dominant X‐linked. NCS showed no response in most of the tested nerves in lower limbs, and normal or reduced amplitudes in upper limbs. A severe sensorineural hearing impairment and a focal epileptic seizure were observed in one patient each. A high intra and inter‐familial clinical variability was observed. Genetic testing found three pathogenic missense variants in GJB1, one in each of the families (Val91Met, Arg15Trp, and Phe235Cys). This is the first report of genetically confirmed cases of CMTX1 in SSA, and confirms its clinical and genetic heterogeneity.
Background and purpose
Hereditary spastic paraplegia (HSP) is a group of neurodegenerative diseases divided into pure and complex forms, with spasticity in lower limbs only, or associated with other ...neurologic and non-neurologic manifestations, respectively. Although widely reported in other populations, very little data exist in sub-Saharan Africa.
Methods
Patients with neurodegenerative features were evaluated over a 19-month period at the Department of Neurology, Teaching Hospital of Point “G”, Bamako, Mali. The diagnosis of HSP was considered based on family history and the absence of other known non-genetic causes. Genetic analysis including candidate gene and whole exome sequencing was performed and variant pathogenicity was tested using prediction tools and ACMG guidelines.
Results
Of the 170 families with hereditary neurological disorders enrolled, 16 had features consistent with HSP, a frequency of 9%. The average age of onset was 14.7 years with 46% starting before age 6. The male/female ratio was 2.6:1. Complex forms were seen in 75% of cases, and pure forms in 25%. Pyramidal findings were present in all patients. Associated features included mental retardation, peripheral neuropathy, epilepsy, oculomotor impairment and urinary urgency. Most patients were treated with a muscle relaxant and physical therapy, and restorative surgery was done in one. Genetic testing identified novel variants in three families (19%).
Conclusion
This study confirms the clinical variability of HSPs and adds African data to the current literature.
Background: There is exponential growth in the interest and implementation of genomics research in Africa. This growth has been facilitated by the Human Hereditary and Health in Africa (H3Africa) ...initiative, which aims to promote a contemporary research approach to the study of genomics and environmental determinants of common diseases in African populations.
Objective: The purpose of this article is to describe important challenges affecting genomics research implementation in Africa.
Methods: The observations, challenges and recommendations presented in this article were obtained through discussions by African scientists at teleconferences and face-to-face meetings, seminars at consortium conferences and in-depth individual discussions.
Results: Challenges affecting genomics research implementation in Africa, which are related to limited resources include ill-equipped facilities, poor accessibility to research centers, lack of expertise and an enabling environment for research activities in local hospitals. Challenges related to the research study include delayed funding, extensive procedures and interventions requiring multiple visits, delays setting up research teams and insufficient staff training, language barriers and an underappreciation of cultural norms. While many African countries are struggling to initiate genomics projects, others have set up genomics research facilities that meet international standards.
Conclusions: The lessons learned in implementing successful genomics projects in Africa are recommended as strategies to overcome these challenges. These recommendations may guide the development and application of new research programs in low-resource settings.
Background
Charcot‐Marie‐Tooth (CMT) disease is a very heterogeneous neurological condition with more than 90 reported genetic entities. It is the most common inherited peripheral neuropathy; ...however, cases are rarely reported in sub‐Saharan Africa. In addition, only few families, mostly of Caucasian ancestry, have been reported to have Charcot‐Marie‐Tooth disease type 2D (CMT2D) mutations. To date no case of CMT2D was reported in Africa. We present here a consanguineous family with CMT phenotype in which a novel mutation in the GARS (glycyl‐tRNA synthetase) gene was identified.
Methods
Patients were examined thoroughly and nerve conduction studies (NCS) were performed. DNA from the proband was used for CMT gene panel testing (including 50 genes, PMP22 duplication and mtDNA). Putative mutations were verified in all available family members to check for segregation.
Results
Two individuals, a male and a female, were found to be affected. Symptoms started in their teenage years with muscle weakness and atrophy in hands. Later, distal involvement of the lower limbs was noticed. Patients complained of minor sensory impairment. NCS showed no response in the upper as well as the lower limbs. Genetic testing surprisingly identified a novel heterozygous missense mutation c.794C>A (p.Ser265Tyr) in the GARS gene associated with CMT2D. This variant segregated with the disease in the family and was also seen in the mother who presented no symptoms.
Conclusion
This is the first report of a genetically confirmed CMT2D case in Africa, expanding its genetic epidemiology. Increasing access to genetic testing may reveal more novel CMT variants or genes in the African population that could be relevant to other populations and further our understanding of their mechanism.
The CMT2D is a rare subtype of CMT with only few cases reported worldwide. We report here a novel mutation in the GARS gen in a Malian family, probably the first case in Africa.
Friedreich ataxia is the most common inherited ataxia in the world, but yet to be reported in black African. We report the first genetically confirmed case in a West African family. Studying genetic ...diseases in populations with diverse backgrounds may give new insights into their pathophysiology for future therapeutic targets.
Friedreich ataxia is the most common inherited ataxia in the world, but yet to be reported in black African. We report the first genetically confirmed case in a West African family. Studying genetic diseases in populations with diverse backgrounds may give new insights into their pathophysiology for future therapeutic targets.
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by mutation in the HTT gene and characterized by involuntary movements as well as cognitive and behavioral ...impairment. Since its first description 150 years ago, studies have been reported worldwide. However, genetically confirmed cases have been scarce in Africa.
To describe the clinical and genetic aspects of HD in the Malian population.
Patients with HD phenotype and their relatives were enrolled after obtaining consent. Symptoms were assessed using the Total Motor Scale (TMS) of the United Huntington's Disease Rating Scale (UHDRS) and the Mini-Mental State Examination (MMSE). Brain imaging and blood tests were performed to exclude other causes. DNA was extracted for HTT sequencing.
Eighteen patients (13 families) with a HD phenotype were evaluated. A familial history of the disease was found in 84.6% with 55.5% of maternal transmission. The average length of the HTT CAG repeat was 43.6±11.5 (39-56) CAGs. The mean age at onset was 43.1±9.7years. Choreic movements were the predominant symptoms (100% of the cases) with an average TMS of 49.4±30.8, followed by cognitive impairment (average MMSE score: 23.0±12.0) and psychiatric symptoms with 22.2% and 44.4%, respectively.
This is one of the largest HD cohorts reported in Africa. Increasing access to genetic testing could uncover many other HD cases and disease-modifying genetic variants. Future haplotype and psychosocial studies may inform the origin of the Malian mutation and the impact of the disease on patients and their relatives.
PDF
