Machado Joseph-Disease Is Rare in the Peruvian Population

Spinocerebellar ataxia type 3 or Machado-Joseph disease (MJD/SCA3) is the most prevalent autosomal dominant cerebellar ataxia worldwide, but its frequency varies by geographic region. We describe MJD/SCA3 patients diagnosed in a tertiary healthcare institution in Peru. In a cohort of 341 individuals (253 probands) with clinical ataxia diagnosis, seven MJD/SCA3 probands were identified and their pedigrees extended, detecting a total of 18 MJD/SCA3 cases. Out of 506 alleles from all probands from this cohort, the 23-CAG repeat was the most common ATXN3 allele (31.8%), followed by the 14-CAG repeat allele (26.1%). Normal alleles ranged from 12 to 38 repeats while pathogenic alleles ranged from 64 to 75 repeats. We identified 80 large normal (LN) alleles (15.8%). Five out of seven families declared an affected family member traced back to foreign countries (England, Japan, China, and Trinidad and Tobago). MJD/SCA3 patients showed ataxia, accompanied by pyramidal signs, dysarthria, and dysphagia as well as abnormal oculomotor movements. In conclusion, ATXN3 allelic distribution in non-MJD/SCA3 patients with ataxia is similar to the distribution in normal individuals around the world, whereas LN allele frequency reinforces no correlation with the frequency of MJD/SCA3. Evidence of any atypical MJD/SCA3 phenotype was not found. Furthermore, haplotypes are required to confirm the foreign origin of MJD/SCA3 in the Peruvian population.

Juvenile-Onset Huntington's Disease in Peru: A Case Series of 32 Patients

Background

Juvenile-onset Huntington's Disease (JoHD) or Huntington's disease (HD) with age of onset ≤20 years, is a rare clinical entity that often differs phenotypically from adult HD and represents only 1-15% of total HD cases.

Objective

To characterize the genetic and clinical characteristics of 32 JoHD patients seen in a Peruvian Neurogenetics clinic from 2000-2018.

Methods

This study is a retrospective clinical and genetic review. The clinical database in Lima, Peru was searched for HD patients seen in clinic between 2000 and 2018. Inclusion criteria were: (1) genetically confirmed disease; and (2) HD age of onset ≤20 years, according to the documented medical history.

Results

Among 475 patients with genetically confirmed HD in the database, 32 patients (6.7%) had symptom onset at ≤20 years. Among JoHD patients with a known transmitting parent (30 of 32), paternal transmission accounted for 77% of cases. Anticipation was higher with paternal transmission compared to maternal transmission (27.5 ± 11.5 vs. 11.3 ± 7.1 years). Overall expanded CAG repeat length ranged from 44 to 110, with a mean length of 65.6 ± 15.4, and 14 (44%) cases had repeat length under 60. Of the 32 patients included in the study, 25 had detailed clinical symptomatology available, and many patients had unique clinical features such as prominent sleep disturbance (60% of patients), or parkinsonism (73%).

Conclusions

This large case series of JoHD patients characterizes the Peruvian JoHD population, reports on unique familial relationships in JoHD, and highlights the varied symptomatic presentation of this rare disease.

Polygenic risk prediction and SNCA haplotype analysis in a Latino Parkinson's disease cohort

BACKGROUND

Large-scale Parkinson's disease (PD) genome-wide association studies (GWAS) have, until recently, only been conducted on subjects with European-ancestry. Consequently, polygenic risk scores (PRS) constructed using PD GWAS data are likely to be less predictive when applied to non-European cohorts.

METHODS

Using GWAS data from the largest study to date, we constructed a PD PRS for a Latino PD cohort (1497 subjects from LARGE-PD) and tested it for association with PD status and age at onset. We validated the PRS performance by testing it in an independent Latino cohort (448 subjects) and by repeating the analysis in LARGE-PD with the addition of 440 external Peruvian controls. We also tested SNCA haplotypes for association with PD risk in LARGE-PD and a European-ancestry PD cohort.

RESULTS

The GWAS-significant PD PRS had an area under the receiver-operator curve (AUC) of 0.668 (95% CI: 0.640-0.695) in LARGE-PD. The inclusion of external Peruvian controls mitigated this result, dropping the AUC 0.632 (95% CI: 0.607-0.657). At the SNCA locus, haplotypes differ by ancestry. Ancestry-specific SNCA haplotypes were associated with PD status in both LARGE-PD and the European-ancestry cohort (p-value < 0.05). These haplotypes both include the rs356182 G-allele, but only share 14% of their variants overall.

CONCLUSION

The PD PRS has potential for PD risk prediction in Latinos, but variability caused by admixture patterns and bias in a European-ancestry PD PRS data limits its utility. The inclusion of diverse subjects can help elucidate PD risk loci and improve risk prediction in non-European cohorts.

Characterizing the Genetic Architecture of Parkinson's Disease in Latinos

OBJECTIVE

This work was undertaken in order to identify Parkinson's disease (PD) risk variants in a Latino cohort, to describe the overlap in the genetic architecture of PD in Latinos compared to European-ancestry subjects, and to increase the diversity in PD genome-wide association (GWAS) data.

METHODS

We genotyped and imputed 1,497 PD cases and controls recruited from nine clinical sites across South America. We performed a GWAS using logistic mixed models; variants with a p-value <1 × 10^-5 were tested in a replication cohort of 1,234 self-reported Latino PD cases and 439,522 Latino controls from 23andMe, Inc. We also performed an admixture mapping analysis where local ancestry blocks were tested for association with PD status.

RESULTS

One locus, SNCA, achieved genome-wide significance (p-value <5 × 10^-8 ); rs356182 achieved genome-wide significance in both the discovery and the replication cohorts (discovery, G allele: 1.58 OR, 95% CI 1.35-1.86, p-value 2.48 × 10^-8 ; 23andMe, G allele: 1.26 OR, 95% CI 1.16-1.37, p-value 4.55 × 10^-8 ). In our admixture mapping analysis, a locus on chromosome 14, containing the gene STXBP6, achieved significance in a joint test of ancestries and in the Native American single-ancestry test (p-value <5 × 10^-5 ). A second locus on chromosome 6, containing the gene RPS6KA2, achieved significance in the African single-ancestry test (p-value <5 × 10^-5 ).

INTERPRETATION

This study demonstrated the importance of the SNCA locus for the etiology of PD in Latinos. By leveraging the demographic history of our cohort via admixture mapping, we identified two potential PD risk loci that merit further study. ANN NEUROL 2021.

Genome-Wide Analysis of Copy Number Variation in Latin American Parkinson's Disease Patients

BACKGROUND

Parkinson's disease is the second most common neurodegenerative disorder and affects people from all ethnic backgrounds, yet little is known about the genetics of Parkinson's disease in non-European populations. In addition, the overall identification of copy number variants at a genome-wide level has been understudied in Parkinson's patients. The objective of this study was to understand the genome-wide burden of copy number variants in Latinos and its association with Parkinson's disease.

METHODS

We used genome-wide genotyping data from 747 Parkinson's disease patients and 632 controls from the Latin American Research Consortium on the Genetics of Parkinson's disease.

RESULTS

Genome-wide copy number burden analysis showed that patients were significantly enriched for copy number variants overlapping known Parkinson's disease genes compared with controls (odds ratio, 3.97; 95%CI, 1.69-10.5; P = 0.018). PRKN showed the strongest copy number burden, with 20 copy number variant carriers. These patients presented an earlier age of disease onset compared with patients with other copy number variants (median age at onset, 31 vs 57 years, respectively; P = 7.46 × 10-7 ).

CONCLUSIONS

We found that although overall genome-wide copy number variant burden was not significantly different, Parkinson's disease patients were significantly enriched with copy number variants affecting known Parkinson's disease genes. We also identified that of 250 patients with early-onset disease, 5.6% carried a copy number variant on PRKN in our cohort. Our study is the first to analyze genome-wide copy number variant association in Latino Parkinson's disease patients and provides insights about this complex disease in this understudied population. © 2020 International Parkinson and Movement Disorder Society.

Two clusters of Toscana virus meningo-encephalitis in Livorno Province and Elba Island, July-September 2018

BACKGROUND

Toscana virus (TOSV) is an arbovirus transmitted to humans by Phlebotomus spp sandflies. It causes aseptic meningitis and meningoencephalitis with marked seasonality. Here we describe the clinical, microbiological and epidemiological features of two clusters of cases occurred in Tuscany in 2018.

METHODS

A confirmed case was defined as the detection of anti-TOSV IgM and IgG in serum sample, in presence of typical clinical manifestations. We consulted hospital records of hospitalized patients to collect clinical information and obtained epidemiological information from the local health authority investigation report. We telephonically interviewed patients using a standard questionnaire for a 6 months follow-up.

RESULTS

A total of 12 cases of TOSV meningo-encephalitis with onset between 4th of July and 12th of September accessed health care services in the province of Livorno. Eight cases were males with median age 41,5 and four were not resident in the area. Serological investigations confirmed a recent TOSV infection. Eight cases reported visiting Elba Island and four had a possible occupational-related exposure.

CONCLUSIONS

This surge of infection emphasizes the need of information campaigns coupled with adequate surveillance and control interventions against TOSV that, among other arboviruses, is a growing issue of concern in Italy.

Correction to: Genetic Analysis of Hereditary Ataxias in Peru Identifies SCA10 Families with Incomplete Penetrance

The original version of this article unfortunately contained some mistakes in Table 2. The additional row (just above SCA2) with the following information "SCA1, 1(1), 1, 50, 74, 24, 46 and 0/1" should be inserted.

Genetic Analysis of Hereditary Ataxias in Peru Identifies SCA10 Families with Incomplete Penetrance

Relative frequency of hereditary ataxias remains unknown in many regions of Latin America. We described the relative frequency in spinocerebellar ataxias (SCA) due to (CAG)n and to (ATTCT)n expansions, as well as Friedreich ataxia (FRDA), among cases series of ataxic individuals from Peru. Among ataxic index cases from 104 families (38 of them with and 66 without autosomal dominant pattern of inheritance), we identified 22 SCA10, 8 SCA2, 3 SCA6, 2 SCA3, 2 SCA7, 1 SCA1, and 9 FRDA cases (or families). SCA10 was by far the most frequent one. Findings in SCA10 and FRDA families were of note. Affected genitors were not detected in 7 out of 22 SCA10 nuclear families; then overall maximal penetrance of SCA10 was estimated as 85%; in multiplex families, penetrance was 94%. Two out of nine FRDA cases carried only one allele with a GAA expansion. SCA10 was the most frequent hereditary ataxia in Peru. Our data suggested that ATTCT expansions at ATXN10 might not be fully penetrant and/or instability between generations might frequently cross the limits between non-penetrant and penetrant lengths. A unique distribution of inherited ataxias in Peru requires specific screening panels, considering SCA10 as first line of local diagnosis guidelines.

Guillain-Barre syndrome outbreak in Peru: Association with polymorphisms in IL-17, ICAM1, and CD1

Background

Guillain–Barre Syndrome (GBS) is considered a complex disorder with significant environmental effect and genetic susceptibility. Genetic polymorphisms in CD1E, CD1A, IL‐17, and/or ICAM1 had been proposed as susceptibility genetic variants for GBS mainly in Caucasian population. This study explores the association between selected polymorphisms in these genes and GBS susceptibility in confirmed GBS cases reported in mestizo population from northern Peru during the most recent GBS outbreak of May 2018.

Methods

A total of nine nonrelated cases and 11 controls were sequenced for the polymorphic regions of CD1A, CD1E, IL‐17, and ICAM1.

Results

We found a significant protective association between heterozygous GA genotype in ICAM1 (241Gly/Arg) and GBS (p < .047). IL‐17 was monomorphic in both controls and patients. No significant differences were found in the frequency of SNPs in CD1A and CD1E between the group with GBS patients and healthy controls.

Conclusion

ICAM1 polymorphisms might be considered as potential genetic markers of GBS susceptibility. Further studies with larger sample size will be required to validate these findings.

The distribution and risk effect of GBA variants in a large cohort of PD patients from Colombia and Peru

BACKGROUND

Mutations in the glucocerebrosidase (GBA) gene are an important risk factor for Parkinson's disease (PD). However, most GBA genetic studies in PD have been performed in patients of European origin and very few data are available in other populations.

METHODS

We sequenced the entire GBA coding region in 602 PD patients and 319 controls from Colombia and Peru enrolled as part of the Latin American Research Consortium on the Genetics of Parkinson's disease (LARGE-PD).

RESULTS

We observed a significantly higher proportion of GBA mutation carriers in patients compared to healthy controls (5.5% vs 1.6%; OR = 4.3, p = 0.004). Interestingly, the frequency of mutations in Colombian patients (9.9%) was more than two-fold greater than in Peruvian patients (4.2%) and other European-derived populations reported in the literature (4-5%). This was primarily due to the presence of a population-specific mutation (p.K198E) found only in the Colombian cohort. We also observed that the age at onset was significantly earlier in GBA carriers when compared to non-carriers (47.1 ± 14.2 y vs. 55.9 ± 14.2 y; p = 0.0004).

CONCLUSION

These findings suggest that GBA mutations are strongly associated with PD risk and earlier age at onset in Peru and Colombia. The high frequency of GBA carriers among Colombian PD patients (∼10%) makes this population especially well-suited for novel therapeutic approaches that target GBA-related PD.

Genetics and genomics in Peru: Clinical and research perspective

Peruvians currently preserve in their DNA the history of 2.5 million years of human evolution and 150,000 years of migration from Africa to Peru or the Americas. The development of Genetics and Genomics in the clinical and academic field is shown in this review.

Huntington's disease-like disorders in Latin America and the Caribbean

Diseases with a choreic phenotype can be due to a variety of genetic etiologies. As testing for Huntington's disease (HD) becomes more available in previously resource-limited regions, it is becoming apparent that there are patients in these areas with other rare genetic conditions which cause an HD-like phenotype. Documentation of the presence of these conditions is important in order to provide appropriate diagnostic and clinical care for these populations. Information for this article was gathered in two ways; the literature was surveyed for publications reporting a variety of genetic choreic disorders, and movement disorders specialists from countries in Latin America and the Caribbean were contacted regarding their experiences with chorea of genetic etiology. Here we discuss the availability of molecular diagnostics for HD and for other choreic disorders, along with a summary of the published reports of affected subjects, and authors' personal experiences from the regions. While rare, patients affected by non-HD genetic choreas are evidently present in Latin America and the Caribbean. HD-like 2 is particularly prevalent in countries where the population has African ancestry. The incidence of other conditions is likely determined by other variations in ethnic background and settlement patterns. As genetic resources and awareness of these disorders improve, more patients are likely to be identified, and have the potential to benefit from education, support, and ultimately molecular therapies.

Erratum: Variable frequency of LRRK2 variants in the Latin American research consortium on the genetics of Parkinson's disease (LARGE-PD), a case of ancestry

[This corrects the article DOI: 10.1038/s41531-017-0020-6.].

Graves' orbitopathy, idiopathic orbital inflammatory pseudotumor and Epstein-Barr virus infection: a serological and molecular study

OBJECTIVE

One of the hypotheses on the pathogenesis of autoimmune diseases, including Graves' disease (GD) and Graves' orbitopathy (GO), involves bacterial or viral infections. Recently, Epstein-Barr virus (EBV) has been proposed to play a role in the pathogenesis of idiopathic orbital inflammatory pseudotumor (IOIP) in Asians. The aim of the present study was to investigate the possible association of GO with EBV infection/exposure, as compared with IOIP, using serum and tissue samples, as well as primary cultures of orbital fibroblasts.

METHODS

Thirty-one patients were studied, including four with IOIP, ten with GO, nine with GD without GO and eight control patients without IOIP, GD and GO. All patients with IOIP and GO underwent orbital decompression. Control patients underwent palpebral surgery. Fibroadipose orbital tissue samples were collected. Serum anti-EBV antibodies were measured in all patients. EBV-DNA was measured in blood samples, orbital tissue samples and primary cultures of orbital fibroblasts.

RESULTS

Serum assays showed that the vast majority of patients have had a previous exposure to EBV, but no one had an acute infection. EBV-DNA was detected in ~40% of blood samples from GO, GD and control patients, but in none of the IOIP samples. EBV-DNA was not detected in any of the orbital tissue samples tested or in primary cultures of orbital fibroblasts.

CONCLUSIONS

EBV infection does not seem to be associated with GD, GO and IOIP in Caucasians. Whether EBV is involved in IOIP in Asians or other populations remains to be confirmed.

The targetable A1 Huntington disease haplotype has distinct Amerindian and European origins in Latin America

Huntington disease (HD) is a dominant neurodegenerative disorder caused by a CAG repeat expansion in the Huntingtin (HTT) gene. HD occurs worldwide, but the causative mutation is found on different HTT haplotypes in distinct ethnic groups. In Latin America, HD is thought to have European origins, but indigenous Amerindian ancestry has not been investigated. Here, we report dense HTT haplotypes in 62 mestizo Peruvian HD families, 17 HD families from across Latin America, and 42 controls of defined Peruvian Amerindian ethnicity to determine the origin of HD in populations of admixed Amerindian and European descent. HD in Peru occurs most frequently on the A1 HTT haplotype (73%), as in Europe, but on an unexpected indigenous variant also found in Amerindian controls. This Amerindian A1 HTT haplotype predominates over the European A1 variant among geographically disparate Latin American controls and in HD families from across Latin America, supporting an indigenous origin of the HD mutation in mestizo American populations. We also show that a proportion of HD mutations in Peru occur on a C1 HTT haplotype of putative Amerindian origin (14%). The majority of HD mutations in Latin America may therefore occur on haplotypes of Amerindian ancestry rather than on haplotypes resulting from European admixture. Despite the distinct ethnic ancestry of Amerindian and European A1 HTT, alleles on the parent A1 HTT haplotype allow for development of identical antisense molecules to selectively silence the HD mutation in the greatest proportion of patients in both Latin American and European populations.

[Neurogenetics in Peru, example of translational research]

Neurogenetics is an emerging discipline in Peru that links basic research with clinical practice. The Neurogenetics Research Center located in Lima, Peru is the only unit dedicated to the specialized care of neurogenetic diseases in the country. From the beginning, neurogenetics research has been closely linked to the study of Huntington’s Disease (HD), from the PCR genotyping of the HTT gene, to the current haplogroup studies in HD. Research in other monogenic diseases led to the implementation of alternative methodologies for the genotyping of Fragile X and Myotonic Dystrophy Type 1. Both, national and international collaborative efforts have facilitated the discovery of new genetic variants in complex multigenic diseases such as Parkinson’s disease and Alzheimer’s disease. Additionally, multidisciplinary education and mentoring have allowed for the training of new neurogenetics specialists, supporting the sustained growth of the discipline in the country. The promotion of research in Peru has spurred the growth of neurogenetics research, although limitations in infrastructure, technology, and education remain a challenge for the further growth of research in this field.

Clinical and Molecular Features of Late Onset Huntington Disease in a Peruvian Cohort

BACKGROUND

Late onset cases of Huntington disease (HD), with onset ≥60 years, account for up to 20% of HD cases worldwide. Clinical features include mild motor dysfunction with slow progression and cognitive impairment, frequent absence of family history and low number of CAG repeats. The clinical and molecular features of late onset HD is still understudied in Latin America.

OBJECTIVES

To describe the clinical and molecular characteristics of late onset HD in a Peruvian cohort.

METHODS

An observational study was carried out by reviewing the HD registry at the Neurogenetics Research Center-INCN from 2000 to 2014. Genotyping of HTT gene …was confirmed using standard PCR and PAGE in accordance to protocols previously established.

RESULTS

Thirty-one late onset HD cases from 27 pedigrees were identified (9.42% of total HD cases, n = 329), 51.61% were male. Mean age at onset was 64.1 ± 4.2 and CAG repeats mean was 42.5 ± 2.5. We did not find significant correlation between age at onset and CAG repeats. 33.3% of cases were traced back to Cañete valley. Twenty-two cases had a positive family history, 14 of them with paternal transmission. Choreic movements and cognitive impairment were the main existing manifestations reported in this cohort, with lower frequency of psychiatric disturbances.

CONCLUSIONS

This report of late onset HD affected individuals shows a mild phenotype expression of the disease, associated with low range of CAG repeats and up to 30% of cases with absence of clear family history. Cañete valley remains the region with more cases.

Clinical and molecular studies reveal a PSEN1 mutation (L153V) in a Peruvian family with early-onset Alzheimer's disease

Presenilin 1 (PSEN1) gene mutations are found in 30-70% of familial early-onset Alzheimer disease (EOAD) cases (onset <60 years). Prevalence of these mutations is highly variable including ethnic differences worldwide. No Peruvian kindred with familial AD (FAD) have been described. Standardized clinical evaluation and cognitive assessment were completed in a Peruvian family with severe EOAD. Clinical course was characterized by very early onset (before age 35 years), progressive cognitive impairment with early memory loss, spatial disorientation and executive dysfunction. We sequenced all exons of PSEN1 in the proband and identified a c.475C>G DNA change resulting in a p.L153V missense mutation in the transmembrane domain 2 of the gene. This mutation is also present in the three additional affected siblings but not in a non-affected family member consistent with segregation of this mutation with the disease. This is the first report of a Peruvian family affected with EOAD associated with a PSEN1 mutation. This same mutation has been reported previously in English and French families, but a novel variants very close to the mutation and ancestry informative markers analysis suggests the mutation might be of Amerindian or African origin in this Peruvian family.

Asociación entre el polimorfismo genético de la apolipoproteína E (ApoE) y la enfermedad de Parkinson

En nuestro país, con el incremento en la esperanza de vida, existe una tendencia creciente de enfermedades neurodegenerativas, por lo que se hace necesario realizar estudios sobre factores de riesgo genético en personas afectadas con la enfermedad de Parkinson (EP), entre ellos el gen de la apolipoproteína E (ApoE), ya que esta asociación es desconocida en nuestra población. Objetivo: Determinar la asociación del polimorfismo en el gen ApoE con la EP. Diseño: Estudio asociativo, observacional tipo casos y controles. Lugar: Instituto Nacional de Ciencias Neurológicas, Lima, Perú. Participantes: Personas de ambos sexos, 163 pacientes con la EP y 176 controles. Intervenciones: Extracción de ADN genómico según metodología estándar. Análisis del gen APOE mediante técnica PCR-RFLP. Principales medidas de resultados: Frecuencias genotípicas y alélicas del gen ApoE en los casos y controles, medidas de asociación y de riesgo. Resultados: No se encontró diferencias significativas entre el grupo control y los pacientes según genotipo de ApoE. La frecuencia del alelo ε4 fue similar en pacientes y en controles. El odds ratio para el alelo ε4 de la ApoE fue 1,0852 (IC 95%: 0,5812 a 2,0266). La edad de inicio de la EP no tuvo relación con los genotipos ApoE. Conclusiones: El alelo ε4 de la ApoE no podría ser considerado un factor de riesgo para la EP, y los genotipos de la ApoE no se asociaron con la edad de inicio en esta muestra evaluada.

[Kennedy disease in Peru: first cases with molecular diagnosis]

Kennedy's disease is an X-linked recessive disorder with onset in adulthood, characterized by progressive degeneration of spinal motor neurons due to a dynamic mutation in the androgen receptor gene. We report three families (five cases) characterized by progressive weakness involving both limbs and bulbar muscles, atrophy, tremor, cramps and endocrinologic disturbances; the neurophysiological studies demonstrated second motor neuron impairment. The molecular analysis identified abnormal CAG repeats expansion in the androgen receptor gene (AR) in all cases. Clinical features were consistent with other previous reports. These are the first Peruvian cases of Kennedy's disease with confirmed molecular diagnosis.

Absence of xenotropic murine leukemia virus-related virus in Italian patients affected by chronic fatigue syndrome, fibromyalgia, or rheumatoid arthritis

The xenotropic murine leukemia virus-related virus (XMRV) has been recently linked to chronic fatigue syndrome in a US cohort in whom the virus was demonstrated in 67&#x0025; patients vs 3.7&#x0025; healthy controls. Albeit this finding was not substantiated by subsequent reports and eventually considered a laboratory contamination, the matter is still the object of intense debate and scrutiny in various cohorts of patients. In this work we examined well-clinically characterized Italian patients affected by chronic fatigue syndrome, and also fibromyalgia and rheumatoid arthritis, two chronic illnesses of basically unknown etiology which show quite a few symptoms in common with chronic fatigue syndrome. Although we used recently updated procedures and controls, the XMRV was not found in 65 patients with chronic fatigue syndrome diagnosis, 55 with fibromyalgia, 25 with rheumatoid arthritis, nor in 25 healthy controls. These results add to the ever-growing number of surveys reporting the absence of XMRV in chronic fatigue syndrome patients and suggest that the virus is also absent in fibromyalgia and rheumatoid arthritis.

[Genetic polymorphism of apolipoprotein E in a Peruvian population]

OBJECTIVES

To determine the allelic and genotypic frequencies of the APOE gene in a sample of a population group in Peru.

MATERIALS AND METHODS

Cross-sectional analytic study in 189 apparently healthy volunteers, workers of the Instituto Nacional de Ciencias Neurológicas in Lima, Perú, divided into 5 groups by birth department and two generations ancestry. Genomic DNA was amplified using PCR-RFLP. The resulting fragments were detected by 12 % polyacrylamide gel electrophoresis.

RESULTS

The ε3 allele is the most frequent in all the groups (93.9 %), with low ε4 (5 %) and ε2 (1.1 %) allele frequencies. The analysis of heterozygosity (H) for each group displays intermediate diversity between 10 and 20%. Population genetic diversity (Ht) and diversity within populations (Hs) are 14.43 % and 14.31% respectively, suggesting genetic proximity between the studied groups for the ApoE polymorphism.

CONCLUSIONS

Allele frequencies of the ApoE gene found show that allele ε3 has one of the highest frequencies and ε4 allele one of the lowest compared to other population groups in the world, with possible implications in the risk of neurological, cardiovascular and other diseases in our country.

Xenotropic murine leukaemia virus-related virus is not found in peripheral blood cells from treatment-naive human immunodeficiency virus-positive patients

The human pathogen xenotropic murine leukaemia virus-related virus (XMRV) has been tentatively associated with prostate cancer and chronic fatigue syndrome. Unfortunately, subsequent studies failed to identify the virus in various clinical settings. To determine whether XMRV circulates in humans and the relationship with its host, we searched for the virus in 124 human immunodeficiency virus-infected patients who might have been exposed to XMRV, might be prone to infection as a result of progressive immunodeficiency, and had not yet been treated with antiretroviral drugs. Using nested PCR and single-step TaqMan real-time PCR, both designed on the XMRV gag gene, we could not find any positive samples. These findings add to the growing amount of scepticism regarding XMRV.

Lrrk2 p.Q1111H substitution and Parkinson's disease in Latin America

Mutations in the LRRK2 gene are the most common genetic cause of Parkinson's disease, with frequencies displaying a high degree of population-specificity. Although more than 100 coding substitutions have been identified, only seven have been proven to be highly penetrant pathogenic mutations. Studies however are lacking in non-white populations. Recently, Lrrk2 p.Q1111H (rs78365431) was identified in two affected Hispanic brothers and absent in 386 non-Hispanic white healthy controls. We therefore screened this variant in 1460 individuals (1150 PD patients and 310 healthy controls) from 4 Latin American countries (Peru, Chile, Uruguay and Argentina). In our case-control series from Peru and Chile we observed an increased frequency of Lrrk2 p.Q1111H in patients (7.9%) compared to controls (5.4%) although the difference did not reach significance (OR 1.38; p = 0.10). In addition, the frequency of Lrrk2 p.Q1111H varied greatly between populations and further screening in a set of pure Amerindian and pure Spanish controls suggested that this variant likely originated in an Amerindian population. Further studies in other Latin American populations are warranted to assess its role as a risk factor for Parkinson's disease. Screening in Parkinson's disease patients from under-represented populations will increase our understanding of the role of LRRK2 variants in disease risk worldwide.

Effects of feline immunodeficiency virus on feline monocyte-derived dendritic cells infected by spinoculation

During type 1 human immunodeficiency virus infection, not only can dendritic cells (DCs) prime T cells against the virus, but they can also infect them in trans. Feline AIDS is caused by feline immunodeficiency virus (FIV) and is considered a model for the human illness because the two diseases have many features in common. Little is known about the interaction of feline DCs with FIV; therefore, this study attempts to tackle such an issue. Infection of feline monocyte-derived DCs (MDDCs) was attempted by spinoculation with FIV strains Petaluma (FIV-Pet) and M2. FIV-Pet was released rapidly in the supernatants of both infected MDDCs and activated T cells after spinoculation. It is shown that FIV-Pet was produced by MDDCs by monitoring viral content in the supernatants of infected MDDCs, by intracellular staining for p25 and by showing its cytopathic effect. Although activated T cells were better substrates for FIV replication, leading to prolonged viral shedding, both immature MDDCs and MDDCs matured with lipopolysaccharide supported virus production, mostly during the first 2 days after infection. At later times, FIV induced syncytium formation by MDDCs. Concerning the FIV receptors, MDDCs were shown to be CD134-negative and CXCR4-positive, a phenotype compatible with permissiveness to FIV-Pet. These results also suggest that maturation is not hampered by FIV infection and that virus exposure itself does not induce MDDC maturation. It is also shown that infected MDDCs can infect activated PBMCs efficiently in trans. It is concluded that MDDCs can be infected by FIV, although infection does not appear to influence their functionality.

Evaluation of feline immunodeficiency virus ORF-A mutants as candidate attenuated vaccine

Feline immunodeficiency virus (FIV) made defective in the accessory gene ORF-A were previously shown to be greatly attenuated in its ability to replicate in lymphocytes but to grow normally or near normally in other cell types. Here, we examined whether FIV thus mutated could protect specific pathogen-free cats against challenge with ex vivo fully virulent homologous virus. No reversion of the vaccinating infections to wild type ORF-A was noted over 22 months of in vivo infection. Following challenge, 6/6 unvaccinated control cats became readily and heavily infected. In contrast, 3/9 vaccinees showed no evidence of the challenge virus over a 15-month observation period. In the other vaccinees, the challenge virus was predominant for various periods of time, but pre-existing viral loads and CD4 lymphocyte counts were either unaffected or altered only marginally and transiently. These findings show that ORF-A-defective FIV should be further examined as a candidate live attenuated vaccine.

Development of feline immunodeficiency virus ORF-A (tat) mutants: in vitro and in vivo characterization

A functional ORF-A is essential for efficient feline immunodeficiency virus replication in lymphocytes. We have characterized a series of mutants of the Petaluma strain, derived from p34TF10 and having different combinations of stop codons and increasingly long deletions in ORF-A. Six clones proved fully replicative in fibroblastoid Crandell feline kidney cells and monocyte-derived macrophage cultures but failed to replicate in T cell lines and primary lymphoblasts. Cats inoculated with three selected mutants had considerably milder infections than controls given intact ORF-A virus. In vivo, the mutants maintained growth properties similar to those in vitro for at least 7 months, except that replication in lymphoid cells was strongly reduced but not ablated. One mutant underwent extensive ORF-A changes without, however, reverting to wild-type. Antiviral immune responses were feeble in all cats, suggesting that viral loads were too low to represent a sufficiently powerful antigenic stimulus.

Densitometric analysis of Western blot assays for feline immunodeficiency virus antibodies

Western blot (WB) strips for antibodies directed to feline immunodeficiency virus (FIV) were analysed using reflectance densitometry by a semiautomatic densitometer. This method was used to quantify the antibody responses to different FIV proteins in both vaccinated and naturally or experimentally-infected cats. In order to increase reproducibility, reagents and protocols were accurately standardised and internal controls were added. In a first format, an internal control band consisting of feline IgG was added to each blot to minimise the effect of band intensity variation. In a second format, antibody concentrations were calculated from the ratio of the densities produced by test sera and by positive and negative standard sera. The sera under scrutiny were also examined by standard enzyme-linked immunosorbent assay (ELISA) and the results obtained compared with those of the corresponding WB. A statistically significant positive correlation was found between the results obtained with the two methods, and this was especially evident when ELISA titres were compared to corrected WB values (P = 0.001). Densitometric analysis of WB assays allowed to quantify the antibodies against FIV proteins and might be useful to investigate possible humoral immune correlates of protection in FIV vaccination studies and antibody production in the early phase of infection. The quantitation of antibodies to Gag and Env FIV antigens might be used to obtain further informations on the course of FIV disease, as previously demonstrated in human immunodeficiency virus-1 (HIV-1) infections.

[The transplant coordinator]

Spain was the first European country adopting a strategy of organ procurement based on a specific health professional named transplant coordinator, who was first established in Catalunya in the middle eighties. In principle, the transplant coordinator is a doctor with hospital experience who is involved full time in organ procurement. The transplant coordination activity is available without interruption, due to a team work. Transplant coordination is based on four main functions: clinical, research, training and communication, management. The principles of transplant coordination according to the Spanish model are reported in the recently approved Italian law on transplantation (law 91/1999), indicating the coordinator's specific functions: a) communication to the regional reference centre of the data concerning the possible organ donors, b) preparation of the documents needed, c) relationship with the donors' family, d) information and education of the population on transplantation issues.

Immunogenicity of an anti-clade B feline immunodeficiency fixed-cell virus vaccine in field cats

Attempts at vaccine development for feline immunodeficiency virus (FIV) have been extensive, both because this is a significant health problem for cats and because FIV may be a useful vaccine model for human immunodeficiency virus. To date, only modest success, producing only short-term protection, has been achieved for vaccine trials in controlled laboratory settings. It is unclear how relevant such experiments are to prevention of natural infection. The current study used a vaccine that employs cell-associated FIV-M2 strain fixed with paraformaldehyde. Subject cats were in a private shelter where FIV was endemic, a prevalence of 29 to 58% over an 8-year observation period. Cats roamed freely from the shelter through the surrounding countryside but returned for food and shelter. After ensuring that cats were FIV negative, they were immunized using six doses of vaccine over a 16-month period and observed for 28 months after the initiation of immunization. Twenty-six cats (12 immunized and 14 nonimmunized controls) were monitored for a minimum of 22 months. Immunized cats did not experience significant adverse effects from immunization and developed both antibodies and cellular immunity to FIV, although individual responses varied greatly. At the conclusion of the study, 0 of 12 immunized cats had evidence of FIV infection, while 5 of 14 control cats were infected. Thus, the vaccine was safe and immunogenic and did not transmit infection. Furthermore, vaccinated cats did not develop FIV infection in a limited clinical trial over an extended time period. Thus, the data suggest that a fixed, FIV-infected cell vaccine has potential for preventing natural FIV infection in free-roaming cats.

AIDS vaccination studies using feline immunodeficiency virus as a model: immunisation with inactivated whole virus suppresses viraemia levels following intravaginal challenge with infected cells but not following intravenous challenge with cell-free virus

The feline immunodeficiency virus (FIV) provides an excellent model system for AIDS vaccination studies. In the present experiments we investigated the immunogenicity and the protective activity of two inactivated vaccines prepared from a primary virus isolate. One vaccine was composed of whole virus inactivated with paraformaldehyde and then purified (WIV) and the other of viral proteins extracted with Tween-ether (TEV). Both vaccines elicited robust antiviral responses, but neither conferred appreciable levels of resistance against systemic challenge with the homologous virus. In addition, we tested whether the WIV vaccine, that had appeared more immunogenic, could protect against nontraumatic intravaginal exposure to FIV-infected cells. Although the proportions of control and vaccinated animals that became infected following mucosal challenge were similar, the vaccinees had significantly lower viral burdens than the controls, thus suggesting that immunisation with the WIV vaccine had limited FIV replication following intravaginal challenge.

Polyneuropathy in autosomal dominant cerebellar ataxias: phenotype-genotype correlation

Autosomal dominant cerebellar ataxias (ADCAs) are clinically and genetically heterogeneous neurodegenerative disorders. The aim of this study was to evaluate electrophysiologically peripheral nervous system involvement in each of the groups studied and its correlation with the number of CAG repeats. Forty patients with ADCA were clinically and electrophysiologically investigated. Thirty-five patients belonged to the ADCA type I group (SCA1, 12; SCA2, 10; SCA3, 13) and five to the ADCA type II group. Axonal sensory or sensorimotor polyneuropathy was found in 42% of the SCA1 patients, 80% of the SCA2 patients, and 54% of the SCA3 patients, whereas electrophysiological studies were normal in all those with ADCA type II. The number of CAG repeats was significantly higher in SCA1 patients with polyneuropathy than in those without polyneuropathy (P = 0.01), whereas the reverse was observed in SCA3/MJD (Machado-Joseph disease) patients (P = 0.05). We conclude that axonal polyneuropathy is often associated with ADCA type I, but its frequency varies according to factors such as the locus responsible and the number of CAG repeats.

Kinetics of replication of a partially attenuated virus and of the challenge virus during a three-year intersubtype feline immunodeficiency virus superinfection experiment in cats

The effects of preinfecting cats with a partially attenuated feline immunodeficiency virus (FIV) on subsequent infection with a fully virulent FIV belonging to a different subtype were investigated. Eight specific-pathogen-free cats were preinfected with graded doses of a long-term in vitro-cultured cell-free preparation of FIV Petaluma (FIV-P, subtype A). FIV-P established a low-grade or a silent infection in the inoculated animals. Seven months later, the eight preinfected cats and two uninfected cats were challenged with in vivo-grown FIV-M2 (subtype B) and periodically monitored for immunological and virological status. FIV-P-preinfected cats were not protected from acute infection by FIV-M2, and the sustained replication of this virus was accompanied by a reduction of FIV-P viral loads in the peripheral blood mononuclear cells and plasma. However, from 2 years postchallenge (p.c.) until 3 years p.c., when the experiment was terminated, preinfected cats exhibited reduced total viral burdens, and some also exhibited a diminished decline of circulating CD4(+) T lymphocytes relative to control cats infected with FIV-M2 alone. Interestingly, most of the virus detected in challenged cats at late times p.c. was of FIV-P origin, indicating that the preinfecting, attenuated virus had become largely predominant. By the end of follow-up, two challenged cats had no FIV-M2 detectable in the tissues examined. The possible mechanisms underlying the interplay between the two viral populations are discussed.

AIDS vaccination studies using an ex vivo feline immunodeficiency virus model: detailed analysis of the humoral immune response to a protective vaccine

The feline immunodeficiency virus (FIV) cat model is extensively used to investigate possible vaccination approaches against AIDS in humans. Although consistent levels of protection have been achieved with FIV, as with other model systems, by immunizing with whole inactivated virus or fixed infected cells, the mechanisms responsible for protection are elusive. In previous studies we showed that cats immunized with a vaccine consisting of fixed infected cells were protected or unprotected against cell-free or cell-associated FIV challenge depending on the time interval between completion of vaccination and challenge. In an attempt to define possible humoral immune correlates of protection, selected sera harvested at the times of challenge from such cats were examined for anti-FIV-antibody titers and properties by using binding and functional immunological assays. Binding assays included quantitative Western blotting, enzyme-linked tests for antibodies to FIV glycoproteins and immunodominant linear epitopes, and tests for measuring conformation dependence and avidity of anti-viral-envelope antibodies. Functional assays included virus neutralization performed with two different cell substrates, complement- and antibody-dependent virolysis, blocking of reverse transcriptase, and an assay that measured the ability of sera to prevent FIV growth in cocultures of infected and uninfected cells. Despite the wide spectrum of parameters investigated, no correlation between vaccine-induced protection and the humoral parameters measured was noted.

AIDS vaccination studies using an ex vivo feline immunodeficiency virus model: homologous erythrocytes as a delivery system for preferential immunization with putative protective antigens

Feline immunodeficiency virus (FIV) is a useful model for testing of criteria for AIDS vaccine development. In the protocol we adopted, we used a primary isolate of FIV as a source of antigen and, for challenge, plasma from cats infected with the homologous virus never passaged in vitro. Cat erythrocytes (RBC) were coated with the surface components of freshly harvested and purified FIV by means of biotin-avidin-biotin bridges and used to immunize specific-pathogen-free cats (four doses at monthly intervals; total amount of FIV antigen administered per cat, approximately 14 microg). Immunized cats developed moderate levels of antibodies directed mainly to surface components of the virion and clearly evident lymphoproliferative responses. Four months after the last dose of immunogen, FIV-immunized cats and control cats immunized with bovine serum albumin-coated RBC were challenged. Judged from the results of the subsequent 12-month follow-up, FIV-immunized cats exhibited at least some degree of protection. However, following rechallenge, most of the FIV-immunized animals became virus positive in spite of a booster immunogen dose given 2 months before the second challenge.

Studies of AIDS vaccination using an ex vivo feline immunodeficiency virus model: protection conferred by a fixed-cell vaccine against cell-free and cell-associated challenge differs in duration and is not easily boosted

Cats immunized with cells infected with a primary isolate of feline immunodeficiency virus (FIV) and fixed with paraformaldehyde were challenged with cell-free or cell-associated homologous virus obtained ex vivo. Complete protection was observed in animals challenged with cell-free virus 4 months after completion of vaccination (p.v.) or with cell-associated virus 12 months p.v. In contrast, no protection was observed in cats challenged with cell-free virus 12 or 28 months p.v. or with cell-associated virus 37.5 months p.v. Prior to the 28- and 37.5-month challenges, the animals had received a booster dose of vaccine that had elicited a robust anamnestic immune response. These results show that vaccine-induced protection against ex vivo FIV is achievable but is relatively short-lived and can be difficult to boost.

Genetic diversity of feline immunodeficiency virus: dual infection, recombination, and distinct evolutionary rates among envelope sequence clades

For the rapid genetic analysis of feline immunodeficiency virus (FIV), we developed a heteroduplex mobility assay (HMA) that utilizes a PCR-amplified fragment of the FIV envelope gene spanning the third and fourth variable regions of the envelope surface protein coding sequence. Viral sequences were successfully amplified from blood specimens from 98 naturally infected cats from Australia, Canada, Germany, Italy, South Africa, and the United States. Eighty were clearly assignable to the A or B envelope sequence subtypes. Three belonged to subtype C, one was dually infected with viruses harboring the A and B env subtypes, and several were categorized as outliers to any of the established subtypes or as probable intersubtype recombinants. Some geographic clustering was evident, with subtypes A and B found in greater frequency in the western and eastern regions of the United States, respectively. Subtypes A, B, and C were found on more than one continent, and countries with more than two samples analyzed contained at least two subtypes. The broadest representation of subtypes was found in Munich, Germany, where three subtypes and one virus that was not classifiable by HMA were found. Thirteen samples were selected for DNA sequence determination over the same region of env used for HMA. Analysis of all available FIV env sequences from this and previous studies revealed the existence of recombinant viruses generated from subtype A/B, B/D, and A/C envelope gene sequences. Subtype A env sequences were less diverse than subtype B sequences, although both groups had well-supported clusters. Furthermore, the mutational pattern giving rise to diversification in the two subtypes differed, with the subtype A viruses showing half as many synonymous site mutations compared to subtype B yet showing similar levels of nonsynonymous site changes. These results are consistent with the hypothesis that FIV-B is an older virus group and is possibly more host adapted than FIV-A.

Incubation time for feline immunodeficiency virus cultures

In a recent report, Fiscus et al. (S. A. Fiscus, S. L. Welles, S. A. Spector, and J. L. Lathey, J. Clin. Microbiol. 33:246-247, 1995) have shown that qualitative human immunodeficiency virus cultures can be terminated at day 21 with minimal false-negative results. We have evaluated a large number of qualitative and quantitative feline immunodeficiency virus (FIV) isolations to determine how long FIV cultures should be incubated to obtain reasonably certain results. The rate at which FIV cultures became positive was influenced by whether the cats under study were naturally or experimentally infected, the duration of in vivo infection, and the number of infected peripheral blood mononuclear cells seeded. The results show that cultures for FIV isolation should be kept for 5 to 6 weeks.