Huntington’s Disease in Africa and the Middle East: A Call for Action

Huntington’s disease (HD) is an autosomal dominant fatal neurodegenerative disorder, characterized by motor, psychiatric, behavioral and cognitive symptoms. The disease is underreported in Africa and the Middle East, where the information on epidemiology and management of HD is scarce. Here we are trying to focus on Huntington’s disease in the region highlighting some of its challenges. 

The Prevalence

The worldwide prevalence of Huntington’s disease is heterogenous and it differs from region to another, with more than tenfold difference between regions across the world1.
Though there are many case reports with Confirmed CAG repeat expansions have been described in different countries across Africa, the prevalence of Huntington’s disease is still underestimated.

In their systematic review, Rawlins and colleagues reported very low prevalence rates among blacks in South Africa (0.02, 95% CI 0–0.5 per 100,000) and Zimbabwe (1.00, 95% CI 0.48–1.84 per 100,000). On the other hand, Baine et al. reported higher prevalence reached 5.1, 2.1 and 0.25 (per 100,000 individuals) for the white, mixed ancestry and black population groups respectively in South Africa.

Reports from North Africa are nonconclusive with a study done in 1994, from which the prevalence of the disease in Egypt was estimated to be 21 per 100,000 to be the height prevalence reported worldwide, since that no other epidemiological studies were done to confirm. Other countries in the region including Tunisia and Morocco2 have some reported cases of HD, still lacking a proximate prevalence of the disease.

Concerning the prevalence of the disease in the Middle East is not yet clear, in 2009 Scrimgeour3 reported an estimate of 3-4 per 100,000 based on few available studies from some countries in the region. In 2019 Squitieri et. al,4 reported a prevalence estimate of 7.36 per 100,000 inhabitants from the Muscat region of the Sultanate of Oman.
There is a need to start national and regional registries for HD cases and to conduct more epidemiological studies to estimate the incidence and prevalence of the disease in Africa and the Middle East.

The Genetics

HD is caused by the presence of an expanded number of CAG repeats in the HTT gene on chromosome 4p16.3.
It worth mentioning that there is high ethnolinguistic and genetic diversity in Africa. Genetic testing for Huntington’s disease was performed in Africa as early as in 1994, mainly in South Africa5, where direct mutation testing for HD has been available. Diagnostic, prenatal, and predictive testing for HD is available in south Africa6, but not in every African country, making the diagnosis even more challenging. Genetic counselling services are provided also in South Africa but very deficient or even absent in other African countries. 

Concerning HTT CAG expanded alleles and haplotypes, compared to European and Caucasian populations, where they are typically found on haplogroup A, in Black African and East Asian populations, they are more commonly found on specific variants of haplogroups AB and C7,8.
Squitieri and colleagues9 investigated the ancestral origin of HD expanded alleles in some families in Oman (a middle eastern country) and showed that most HD families from the Middle East, including three from Oman, shared an A2b haplotype that was similar to Europeans.

A lot of work is needed in these regions to identify the common haplotypes and alleles for future allele specific antisense oligonucleotides therapies for Huntington’s disease.

Another challenge in genetics of HD in Africa is the presence of phenocopies especially Huntington’s disease like type 2 (HDL2) which has different gene location and different repeats; a CTG/CAG expansion mutation in exon 2A of the junctophilin-3 (JPH3) gene on chromosome16q24.310. HDL2 has a clinical picture and radiological findings similar to HD with some subtle changes11.

The availability of genetic services for diagnosis and counselling is highly required in the region in a reasonable price. This necessitates providing good equipment and sufficient training in more centers distributed across the region in Africa and the Middle East and facilitate sample transfer when needed. 

Clinical presentation

The presentation of the disease is variable, with some reports showed psychiatric manifestations were the presenting symptoms at onset, while others reported the abnormal movement to be the first symptoms. Still there is a need to have cohorts to characterize the phenotypes of HD in different countries in the region.

Awareness and supportive groups

There is marked lack of awareness about Huntigton’s disease in Africa and the Middle East, this also contributes to the underreported cases in the region. There is a problem in seeking medical advice, and also a lack of trained neurologists who can recognize and diagnose the disease. There is also lack of the supportive care provided for patients and their caregivers across Africa and middle east. The knowledge about the disease is still in its infancy, with very little resources in local languages to spread awareness.
Recently there are some efforts and initiatives to raise awareness about the disease, for example the Huntington’s disease Africa as an advocacy group https://hd-africa.org/ , for the Middle East there are the Oman’s Huntington’s disease association. There are some initiatives in Egypt to raise awareness by translating some articles and creating some educational materials about the disease in Arabic languages https://ar.hdbuzz.net.

There is a need to connect to the international associations providing support to patients with HD and their families e.g. the international Huntington’s disease association (IHA), The European Huntington’s disease association (EHA) and the Huntington’s disease youth organization (HDYO), and to encourage founding more local and regional associations.

Access to care

The access to care is still limited to patients in Africa and some of other Middle Eastern countries. Not all patients in these regions are covered by health insurance, and they have to pay the high cost of the treatment12. The Multidisciplinary care of managing the disease is also not well established, with little known about the role of non-pharmacological intervention (e.g physiotherapy and speech therapy and how to apply in different stages of the disease). 

Social aspects of the disease

Since 1980 when Hyden and colleagues13 reported the social aspects of HD nothing was mentioned. In their report they discuss the social burden, the suicidality, crimes, and the economic burden. The burden of HD is not discussed at all in the Middle East.

Trained neurologists and specialized centers

As reported by Scrimgeour 2009 the average doctor in the Middle East may never encounter or recognize a case with HD, though there are many cases reported from different countries, this applies also to Africa. Another problem is the inadequate numbers of neurologists in relation to the population number in different countries in Africa and the Middle East.

In order to overcome the problem of lack of trained neurologists, educational courses and fellowships are important and to encourage the enrollment of neurologists as well as non-neurologists involved in the management of HD from the region. This is nicely done by the Movement disorders society (MDS) providing a variety of teaching courses and educational materials about HD. This effort was even more appreciated at the time of COVID-19 pandemic where all courses were available online for free for all MDS members.

Another good opportunity for young neurologists is the EHDN-MDS Fellowship, which provide training on Huntington’s disease at one of expert European centers. Applicants from countries with fewer resources have the chance to stay for six weeks or so and train on the diagnosis and management of the disease, many different aspects of the disease and the current clinical trials.

Another initiative taken by the IHA is to hold meetings for Arabic countries, to introduce the disease from its different aspects and how to deal with patients in different stages.

The first meeting was held on June 25, 2021, in English, hosted by Prof. Bernhard Landwehrmeyer from Ulm, Germany, where many expert speakers in the field will give talks. The meeting provided an overview on HD and its different stages, the motor manifestations, the cognitive and behavioral manifestations, the genetic diagnosis and counselling, caregiver experience in some of Arabic countries, the status of HD in the Middle East, and how to decrease the gap between the Eastern and western countries in HD management.

It is worth mentioning that short survey was conducted on the challenges facing neurologists while managing Huntington’s disease in Egypt. The responses from 140 participants showed that results late diagnosis (31.9%) or misdiagnosed cases, unavailable treatment and no cure (21.3%), lack of awareness about the disease among physicians and public (19.6%), the genetic testing is inadequate, not present in every center (12.3%), lack of multidisciplinary and supportive care (12.3%), less frequent responses included; lack of experienced specialists, rare disease without funding for researches, no specialized centers, lack of facilities for the patients and their families¹⁴.

In concolusion, action is needed in Africa as well as most of countries in the middle to achieve following: implementing national registries, spreading more awareness, providing more educational courses and training opportunities, encouraging collaboration across Africa and middle east as well as international collaboration in fields of patient care and research, Creating more supportive groups for the patients and families for more awareness and to erase the stigma, Providing more information about the disease in different local languages, Fund raising for research on Huntington’s disease in Africa and the Middle east, and to establish specialized HD centers for better care and research.

References:

1. Rawlins M, D, Wexler N, S, Wexler A, R, Tabrizi S, J, Douglas I, Evans S, J, W, Smeeth L: The Prevalence of Huntington's Disease. Neuroepidemiology 2016;46:144-153. doi: 10.1159/000443738
2. Bouhouche A, Regragui W, Lamghari H, Khaldi K, Birouk N, Lytim S, Bellamine S, Kriouile Y, Bouslam N, Haddou el HA, Faris MA, Benomar A, Yahyaoui M. Clinical and genetic data of Huntington disease in Moroccan patients. Afr Health Sci. 2015 Dec;15(4):1232-8. doi: 10.4314/ahs.v15i4.23. PMID: 26958025; PMCID: PMC4765413.
3. Scrimgeour EM. Huntington disease (chorea) in the Middle East. Sultan Qaboos Univ Med J 2009; 9(1): 16-23.
4. Squitieri F, Maffi S, Al Harasi S, et al. J Neurol Neurosurg Psychiatry Epub ahead of print: [please include Day Month Year]. doi:10.1136/jnnp-2020323241
5. Silber E, Kromberg J, Temlett JA, Krause A, Saffer D. Huntington's disease confirmed by genetic testing in five African families. Mov Disord. 1998;13:726–730. 
6. Sizer EB, Haw T, Wessels T, Kromberg JGR, Krause A. The utilization and outcome of diagnostic, predictive, and prenatal genetic testing for Huntington disease in Johannesburg, South Africa. Genet Test Mol Biomarkers. 2011;16:1–6.
7. Baine FK, Kay C, Ketelaar ME, et al. Huntington disease in the South African population occurs on diverse and ethnically distinct genetic haplotypes. Eur J Hum Genet. 2013;21:1120–1127.
8. Kay C, Collins JA, Caron NS, et al. A comprehensive haplotype targeting strategy for allele-specific HTT suppression in Huntington disease. Am J Hum Genet. 2019;105:1112–1125.
9. Squitieri, F., Mazza, T., Maffi, S. et al. Tracing the mutated HTT and haplotype of the African ancestor who spread Huntington disease into the Middle East. Genet Med 22, 1903–1908 (2020). https://doi.org/10.1038/s41436-020-0895-1
10. Baine FK, Krause A, Greenberg LJ. The frequency of Huntington disease and Huntington disease‐like 2 in the South African population. Neuroepidemiology 2016;46(3):198–202.
11. Anderson DG, Ferreira-Correia A, Rodrigues FB, Aziz NA, Carr J, Wild EJ, Margolis RL, Krause A (2019a) Comparison of the Huntington’s disease like 2 and Huntington’s disease clinical phenotypes. Mov Disord Clin Pract 6:302–311
12. Mahdy HM. Huntington’s disease in Arab countries. J Huntingtons Dis 2015;4:205–8. Hayden M.R., Ehrlich R., Parker H., Ferera S.J. Social Perspectives in Huntington's Chorea. S. Afr. med. l., 58, 201 (1980).
13. S. El-Jaafary, A. Sabbah, H. Amer. Huntington’s disease in Egypt; A big challenge for a mysterious disease [abstract]. Mov Disord. 2020; 35 (suppl 1). https://www.mdsabstracts.org/abstract/huntingtons-disease-in-egypt-a-big-challenge-for-a-mysterious-disease/. Accessed June 8, 2021.

https://huntington-disease.org/
http://www.ehdn.org/ 
https://en.hdyo.org/