A comprehensive clinical and genetic study of a large Mexican population with spinocerebellar ataxia type 7.

Spinocerebellar ataxia type 7 (SCA7) is an inherited neurodegenerative disorder characterized by progressive cerebellar ataxia associated with macular degeneration. We recently described one of the largest series of patients with SCA7 that originated from a founder effect in a Mexican population, which allowed us to perform herein the first comprehensive clinical, neurophysiological, and genetic characterization of Mexican patients with SCA7. In this study, 50 patients, categorized into adult or early phenotype, were clinically assessed using standard neurological exams and genotyped using fluorescent PCR and capillary electrophoresis. Patients with SCA7 exhibited the classical phenotype of the disease characterized by cerebellar ataxia and visual loss; however, we reported, for the first time, frontal-executive disorders and altered sensory-motor peripheral neuropathy in these patients. Semiquantitative analysis of ataxia-associated symptoms was performed using Scale for the Assessment and Rating of Ataxia (SARA) and the Brief Ataxia Rating Scale (BARS) scores, while extracerebellar features were measured employing the Inventory of Non-ataxia Symptoms (INAS) scale. Ataxia rating scales confirmed the critical role size of cytosine-adenine-guanine (CAG) repeat size on age at onset and disease severity, while analysis of CAG repeat instability showed that paternal rather than maternal transmission led to greater instability.

Analysis of CAG repeats in five SCA loci in Mexican population: epidemiological evidence of a SCA7 founder effect.

Spinocerebellar ataxias (SCA) are a heterogeneous group of neurodegenerative disorders. CAG (cytosine-adenine-guanine) trinucleotide repeat expansions in the causative genes have been identified as the cause of different SCA. In this study, we simultaneously genotyped SCA1, SCA2, SCA3, SCA6, and SCA7 applying a fluorescent multiplex polymerase chain reaction assay. We analyzed 10 families with SCA (64 patients) from five different communities of Veracruz, a Mexican southeastern state, and identified 55 patients for SCA7 and 9 for SCA2, but none for SCA1, SCA3, or SCA6. To our knowledge, this sample represents one of the largest series of SCA7 cases reported worldwide. Genotyping of 300 healthy individuals from Mexican population and compiled data from different ethnicities showed discordant results concerning the hypothesis that SCA disease alleles arise by expansion of large normal alleles.

[Characterization of Cryptococcus neoformans strains isolated from patients with acquired immunodeficiency syndrome (AIDS)]. / Caracterización de cepas de Cryptococcus neoformans aisladas de pacientes con síndrome de inmunodeficiencia adquirida (SIDA).

In Mexico cryptococosis ranks third in frequency among the mycoses ocurring as complications in AIDS patients. Neither the prevalence of the two varieties of C. neoformans in these patients nor the morphological and physiological changes suffered by these strains in AIDS patients are known. A total of 60 isolates were obtained from patients with AIDS from the Hospital de Infectología, Centro Médico "La Raza" IMSS. The identity of each isolate was established by: growth at 37 degrees C, colony and microscopic characteristics, urease and phenoloxidase activity, carbon sources assimilation. The canavanine glycine-bromothymol blue agar was used to distinguish C. neoformans var. neoformans and C. neoformans var. gattii. Pathogenicity in mice was also tested. Fifty one isolates of C. neoformans var. neoformans and nine of C. neoformans var. gattii were identified. All strains grew well at 37 degrees C, urease and phenoloxidase were positive, the morphology and the auxanographic profile were variable. C. neoformans var. neoformans was more virulent in mouse than C. neoformans var. gattii. This study has confirmed the presence of the two varieties of C. neoformans in Mexico with 85% prevalence of var. neoformans and 15% of var. gattii in AIDS patients. This frequency was higher than in reports from other countries.