Clinical features of multiple sclerosis in a genetically homogeneous tropical population

Native ancestry is associated with optic neuritis and age of onset in hispanics with multiple sclerosis

Background and Objective

Hispanics with multiple sclerosis (MS) present younger and more often with optic neuritis (ON) as compared to Whites in the western United States. Regional differences related to Hispanic genetic admixture could be responsible. We investigated the association between global genetic ancestry and ON and age at onset of MS in Hispanics.

Methods

Data were obtained for 1033 self‐identified Hispanics with MS from four MS‐based registries from four academic institutions across the United States January 2016–April 2017. Multivariate regression models, utilizing genetic ancestry estimates for Native American (NA), African, and European ancestry, were used to assess the relationship between genetic ancestry and ON presentation and age of MS onset, defined as age at first symptom.

Results

Genetic ancestry and ON proportions varied by region where NA ancestry and ON proportions were highest among Hispanics in the southwestern United States (40% vs. 19% overall for NA and 38% vs. 25% overall for ON). A strong inverse correlation was observed between NA and European ancestry (r = −0.83). ON presentation was associated with younger age of onset (OR: 0.98; 95% CI: 0.96–0.99; P = 7.80 × 10⁻⁰³) and increased NA ancestry (OR: 2.35 for the highest versus the lowest quartile of NA ancestry; 95% CI: 1.35–4.10; P = 2.60 × 10⁻⁰³). Younger age of onset was found to be associated with a higher proportion NA (Beta: −5.58; P = 3.49 × 10⁻⁰²) and African ancestry (Beta: −10.07; P = 1.39 × 10⁻⁰³).

Interpretation

Ethnic differences associated with genetic admixture could influence clinical presentation in Hispanics with MS; underscoring the importance of considering genetic substructure in future clinical, genetic, and epigenetic studies in Hispanics.

Multiple Sclerosis Patients with Markedly Low Intrathecal Antibody Response in Sri Lanka

Multiple sclerosis (MS) is a heterogeneous disease which is poorly studied in Asia, where the disease is known to be rare with significant differences in clinical and radiological presentations and intrathecal antibody response. Therefore the objective of this study was to determine clinical presentation, radiological and neurophysiological characteristics, and oligoclonal band status in Sri Lankan MS patients, following careful exclusion of patients with neuromyelitis optica spectrum disorders and other conditions mimicking multiple sclerosis. Sixty-nine MS patients were recruited to the study adhering to McDonald 2010 criteria. Their clinical presentation, characteristics of central nervous system lesions in magnetic resonance imaging, visual evoked potential (VEP) results, oligoclonal bands (OCB), and AQP4 antibody status were studied. Of 69 MS patients, 54%, 6%, and 1% were relapsing remitting, secondary progressive, and primary progressive, respectively, and 39% were patients with clinically isolated syndrome. The commonest clinical presentations were cerebral motor followed by cerebral sensory and optic neuritis. Majority had typical periventricular and infratentorial lesions in MRI. Though not clinically apparent, bilateral delay of P100 wave latency was present in 52%. OCB positivity was 42% and AQP4 antibody was positive in only one patient. In conclusion, this group of Sri Lankan MS patients shares most of the clinical and radiological features of Caucasian MS patients. However, the OCB positivity is lower in this group, when compared to the Caucasian MS populations.

Multiple sclerosis epidemiology in Latin America: An updated survey

Novel epidemiological data have appeared in recent years in Latin America (LATAM). The objective of this study was to perform an updated systematic review of the epidemiology of the disease reported in LATAM.

Spinal cord lesions and disability in Hispanics with multiple sclerosis

Longitudinally extensive spinal cord lesions (LESCLs) are believed to occur predominantly with opticospinal multiple sclerosis (OSMS) and are associated with disability. The purpose of this study is to describe the prevalence and patterns of spinal cord lesions in Hispanics with multiple sclerosis (MS) and OSMS and their association with disability. A cross-sectional study of 164 patients with complete MRIs was used. In each case the spinal cord was classified: LESCLs, scattered spinal cord lesions (sSCLs) or no spinal cord lesions (noSCLs). Clinical course was defined as classical MS or OSMS. Risk of disability (Expanded Disability Status Scale ≥4.0) was adjusted for age, disease duration and sex using logistic regression. A total of 125/164 (73 %) MS patients had spinal cord lesions (sSCLs, 57 %; LESCLs, 19 %), but only 11 (7 %) had OSMS. LESCLs were associated with disability (p < 0.0001), longer disease duration (p < 0.0001) and MS (n = 21 vs. n = 10 OSMS; p < 0.0001). LESCLs were also associated with the greatest risk to disability (OR 7.3, 95 % CIs 1.9-26.5; p = 0.003; sSCLs OR 2.5, 95 % CIs 0.9-7.1; p = 0.09) compared with noSCLs. LESCLs are more common than OSMS and are associated with worse disability even in patients with MS. These results suggest that LESCLs are a more important marker of disability in MS than OSMS and may be an early indicator of more aggressive disease in this population.

The epidemiology of multiple sclerosis in Latin America and the Caribbean: a systematic review

The incidence and prevalence of multiple sclerosis (MS) varies geographically as shown through extensive epidemiological studies performed mainly in developed countries. Nonetheless, scant data is available in Latin America and the Caribbean (LAC). The objective of this review is to assess epidemiological data of MS in LAC. We conducted a systematic review of published articles and gray literature from January 1995 to May 2011. Twenty-two studies met the inclusion criteria after full-text review. Incidence data were found in only three studies and ranged from 0.3 to 1.9 annual cases per 100,000 person-years. Prevalence was reported in 10 studies and ranged from 0.83 to 21.5 cases per 100,000 inhabitants. The most prevalent subtype of MS was the relapsing–remitting form (48% to 91% of the series). No data about mortality were found. This study showed low frequency for MS in LAC compared with North American and European countries. The role of environmental and genetic factors should be well studied, providing new insights about its etiology.

Genetic and environmental backgrounds responsible for the changes in the phenotype of MS in Japanese subjects

There are two distinct phenotypes of multiple sclerosis (MS) in Asians, manifesting as opticospinal (OSMS) and conventional (CMS) forms. In Japan, the results of four nationwide surveys of MS conducted between 1972 and 2004 have revealed a four-fold increase in the estimated number of clinically definite MS patients in 2003 compared with 1972; a shift in the peak age at onset from the early 30s in 1989 to the early 20s in 2003; a successive proportional decrease in optic-spinal involvement in clinically definite MS patients; an increase in the number of CMS patients with Barkhof brain lesions with advancing birth year and a decrease in the number of OSMS patients with LESCLs. These findings suggest that MS phenotypes are drastically altered by environmental factors such as latitude and "Westernization". Helicobacter pylori infection rates, reflecting sanitary conditions in infancy, are significantly different between CMS and OSMS patients. Both phenotypes show distinct HLA class II gene associations. Therefore, changes in environmental factors may have differentially influenced susceptibility to each disease subtype, given that disease susceptibility is only partly genetically determined.

The prevalence of multiple sclerosis in Belo Horizonte, Brazil

Investigations on the prevalence rates of multiple sclerosis (MS) around the world have yielded important clues on the interplay between genetic susceptibility and environmental factors. As Brazil is a huge country laid on many latitudes and inhabited by population with distinct ethnic backgrounds, it might be assumed that the frequency of MS varies in its different regions. Objective: To determine the prevalence rate of MS in Belo Horizonte, the capital of the State of Minas Gerais, Southeastern Brazil. Methods: We used six sources to draw up a provisional list of identified cases of MS. Only patients with diagnosis of clinically definite MS according to Poser Committee criteria were included. Results: The calculated crude MS prevalence was 18.1/100,000 inhabitants. Conclusions: The MS prevalence in Belo Horizonte is similar to that found in São Paulo and Botucatu, two other cities in southeastern Brazil with similar ethnic background.

Multiple sclerosis in Caucasians and Latino Americans

Epidemiological and genetic studies suggest that the prevalence, median age of onset, and specific phenotypes of multiple sclerosis (MS) are different in Caucasians and Latino Americans. Recent epidemiological studies indicate an increase in MS prevalence in Latin America (LA), where the south-north gradient of latitude described for Nordic countries does not exist. Analysis of MS epidemiological and specific aspects in LA suggests that susceptibility and clinical behavior of the disease are related to mixtures and admixtures of genes in the population. MS is not present in Amerindians with Mongoloid genes, such as occurs in other pure ethnic groups. Surely, future studies will be carried out to obtain more reliable information. In this review, we contrast and analyze the available data of MS in LA and endemic countries.

Multiple sclerosis in Hispanics: a study of clinical disease expression

Background: Hispanics living with multiple sclerosis (MS) in the United States are not well defined.

Objective: To describe the clinical characteristics of MS among Hispanic Whites (HW) in Southern California with those of non-Hispanic Whites (NHW).

Methods: We performed a medical chart review to identify all cases of HW with MS ( n = 125) who were treated at our institution during a 1-year period. We also identified cases of NHW with MS (100 NHW) treated at those clinics. All HW patients were interviewed to ascertain ancestry including detailed migration history. Disease progression was assessed by ambulatory disability and defined as Expanded Disability Status Scale (EDSS) score ≥6.

Results: Compared with NHW, HW were more likely to have a relapsing–remitting form of MS and a younger age of onset (28.4 ± 0.97 years) with presenting symptoms of optic neuritis and transverse myelitis. However, overall ambulatory disability did not differ between HW and NHW. Migration to the US at age >15 years was associated with increased risk of disability in HW.

Conclusions: HW living in the USA may be at risk of developing MS at an earlier age compared with NHW. Migration history can play an important role in the management of HW with MS.

Temporal changes and geographical differences in multiple sclerosis phenotypes in Japanese: nationwide survey results over 30 years

Background

There are two distinct phenotypes of multiple sclerosis (MS) in Asians, manifesting as optic-spinal (OSMS) and conventional (CMS) forms. In Japan, four nationwide surveys of MS have been conducted. The first three were in 1972, 1982, and 1989, and we performed the fourth in 2004.

Results

The recent survey showed six main findings as follows: (1) a four-fold increase in the estimated number of clinically definite patients with MS in 2003 (9900; crude MS prevalence, 7.7/100,000) compared with 1972; (2) a shift in the peak age at onset from early 30s in 1989 to early 20s in 2003; (3) a successive proportional decrease in optic-spinal involvement in clinically definite patients with MS; (4) a significant north–south gradient for the CMS/OSMS ratio; (5) after subdivision of the mainland (30–45° North) into northern and southern parts at 37°N, northern-born northern residents (northern patients) showed a significantly higher CMS/OSMS ratio and higher frequency of brain lesions fulfilling the Barkhof criteria (Barkhof brain lesions) than southern-born southern residents (southern patients); (6) among northern patients, the absolute numbers of patients with CMS and those with Barkhof brain lesions rapidly increased with advancing birth year.

Conclusions

These findings suggest that MS phenotypes are drastically altered by environmental factors, such as latitude and “Westernization.”

Central Nervous System Compromise in Primary Sjögren’s Syndrome

Central nervous system (CNS) involvement in primary Sjögren's syndrome (SS) is poorly understood, and its frequency as well as its manifestations are subjects of controversy. The current study was undertaken to determine the prevalence and the clinical and immunogenetic characteristics of CNS compromise in a well defined group of patients with primary SS. In this retrospective study, patients fulfilled the European classification criteria. Among 120 patients with primary SS, 3 (2.5%) had CNS compromise (multiple sclerosis-like illness, complicated migraine, and optic neuritis with epilepsy). The CNS involvement coincided with the onset of sicca symptoms in 1 case. All 3 patients carried the human leukocyte antigen (HLA) DQB1*0303 allele and tested positive for anti-Ro antibodies, but not for anti-cardiolipin antibodies. Although rare, CNS compromise in primary SS can be the presenting manifestation of the disease in a few cases, and may be severe and varied.

Multiple sclerosis in the tropics: genetic association to STR's loci spanning the HLA and TNF

Clear evidence has been presented correlating gene polymorphisms at 6p21.3-21.4 (containing HLA and TNF) and the predisposition to acquire multiple sclerosis (MS). In a previous study, we found that polymorphisms at HLA DQAI were associated with being or not being predisposed to MS in individuals inhabiting the tropics, where the prevalence of MS is significantly lower than in subtropical areas. Here, we tested the hypothesis that polymorphisms at D6S276, D6S265, D6S273 and D6S291 microsatellite loci are in strong linkage disequilibrium with a major genetic factor predisposing to MS. These microsatellites span the 6p21.3 region with intervals of 5 cM establishing particular landmarks for the HLA and TNF loci. Thirty-five MS patients and 35 controls, age, sex, social, ethnically and geographically matched healthy individuals, were studied. After testing the fit of gene frequencies to the normal distribution and performing the correlation for multiple comparisons, we found significant differences among the case and the control frequencies for the allele 202 belonging to the marker D6S276 (Pc=0.00455) and for the allele 114 belonging to the marker D6S265 (Pc=0.0084). For these two alleles at different loci, we found higher frequencies in the cases than in the controls. A nonsignificant p value was found in testing the existence of linkage disequilibrium among the studied loci in the cases and in the controls. In conclusion, the current study adds evidence to the established association among polymorphisms of genes located at 6p21.3-21.4 and MS. Furthermore, because of the distribution of the tested microsatellite loci, the more probable critical region could be correlated with the TNF neighborhood.