REVIEW-ARTICLE Intermediate alleles of Huntington's disease HTT gene in different populations worldwide: a systematic review.

Huntington's disease (HD) is an autosomal dominant progressive neurodegenerative disorder caused by a dynamic mutation due to the expansion of CAG repeats in the HTT gene (4p16.3). The considered normal alleles have less than 27 CAG repeats. Intermediate alleles (IAs) show 27 to 35 CAG repeats and expanded alleles have more than 35 repeats. The IAs apparently have shown a normal phenotype. However, there are some reported associations between individuals that bear an IA and clinical HD signs, such as behavioral disturbs. The association of IAs with the presence of clinical signs gives clinical relevance to these patients. We emphasized the importance of determining the frequency of IA alleles in the general population as well as in HD families. Therefore, the aim of this study was to conduct a systematic review, in order to investigate the frequency of IAs in the overall chromosomes of different ethnic groups and of families with HD history worldwide as well as the frequency of individuals who bear the intermediate alleles. We searched indexed articles from the following electronic databases: U.S. National Library of Medicine and the National Institutes of Health (PubMed), Pubmed Central (PMC) and Virtual Health Library (VHL). Therefore, 488 articles were obtained and, of these, 33 had been published in more than one database. We accepted the article of only one database and ended up with 455 articles for this review. The frequency of IAs within the chromosomes of the general population ranged from 0.45 to 8.7% and of individuals with family history of HD ranged from 0.05 to 5.1%. The higher frequency of IAs in the general population (8.7%) was found in one Brazilian cohort.

Clinical and genetic investigation of a Brazilian family with Huntington's disease.

The aim of this study was to investigate a Brazilian family carrying full penetrance alleles for Huntington's disease (HD) in order to correlate each member's genetic and clinical features. To this end, the following scales were administered in each patient: the Beck Depression Inventory, the Mini-Mental State Examination (MMSE) and the Unified Huntington's Disease Rating Scale (UHDRS). The patterns of CAG and CCG polymorphic regions in the HTT gene were determined, the disease burden score was calculated, and genotypes were correlated with phenotypes within this family. We suggest that HD duration, the number of years of formal education, and UHDRS status variables can explain 96.6% of the MMSE variability in HD patients. A strong significant correlation was found between the disease burden score and the UHDRS (r = 0.76; p-value = 0.049) and the MMSE (r = -0.90; p-value = 0.006). The correlations between CAG allele size and the three clinical evaluations performed in the HD patients were not statistically significant.

Notification of Huntington's disease as primary cause of death in Brazil from 1984 to 2008.

The aim of this article was to conduct a retrospective observational study on reported deaths due to Huntington's disease (HD) in Brazil in the past 25 years (from 1984 to 2008). Data were obtained from the Brazilian Mortality Information System (SIM/DATASUS), the official system of Brazilian Mortality Database. The data obtained included information regarding the gender of the deceased and the number of death notifications, which we stratified by demographic regions and states. HD mortality per 100,000 was calculated and plotted in a graph. Linear regression was calculated using ordinary least square technique. We observed that the mortality due to HD recorded by SIM/DATASUS from 1984 to 2008 had increased at much higher rates than the population in the same period. Also, some Brazilian regions still show very low rates of HD mortality compared to the national average of deaths due to HD. These findings suggest that HD mortality has been underestimated. Ignorance about the disease as well as the fact that death from HD can occur as a consequence of heart disease, pneumonia, or suicide can strongly contribute to the misguided notification of HD as the cause of death in the official reports.

Mini-Review: Monosomy 1p36 syndrome: reviewing the correlation between deletion sizes and phenotypes.

The major clinical features of monosomy 1p36 deletion are developmental delay and hypotonia associated with short stature and craniofacial dysmorphisms. The objective of this study was to review the cases of 1p36 deletion that was reported between 1999 and 2014, in order to identify a possible correlation between the size of the 1p36-deleted segment and the clinical phenotype of the disease. Scientific articles published in the (National Center for Biotechnology Information; NCBI http://www.ncbi.nlm.nih.gov/pubmed) and Scientific Electronic Library Online (www.scielo.com.br) databases were searched using key word combinations, such as "1p36 deletion", "monosomy 1p36 deletion", and "1p36 deletion syndrome". Articles in English or Spanish reporting the correlation between deletion sizes and the respective clinical phenotypes were retrieved, while letters, reviews, guidelines, and studies with mouse models were excluded. Among the 746 retrieved articles, only 17 (12 case reports and 5 series of cases), comprising 29 patients (9 males and 20 females, aged 0 months (neonate) to 22 years) bearing the 1p36 deletions and whose clinical phenotypes were described, met the inclusion criteria. The genotype-phenotype correlation in monosomy 1p36 is a challenge because of the variability in the size of the deleted segment, as well as in the clinical manifestations of similar size deletions. Therefore, the severity of the clinical features was not always associated with the deletion size, possibly because of the other influences, such as stochastic factors, epigenetic events, or reduced penetration of the deleted genes.

Prader-Willi-like phenotypes: a systematic review of their chromosomal abnormalities.

Prader-Willi syndrome (PWS) is caused by the lack of expression of genes located on paternal chromosome 15q11-q13. This lack of gene expression may be due to a deletion in this chromosomal segment, to maternal uniparental disomy of chromosome 15, or to a defect in the imprinting center on 15q11-q13. PWS is characterized by hypotonia during the neonatal stage and in childhood, accompanied by a delay in neuropsychomotor development. Overeating, obesity, and mental deficiency arise later on. The syndrome has a clinical overlap with other diseases, which makes it difficult to accurately diagnose. The purpose of this article is to review the Prader-Willi-like phenotype in the scientific literature from 2000 to 2013, i.e., to review the cases of PWS caused by chromosomal abnormalities different from those found on chromosome 15. A search was carried out using the "National Center for Biotechnology Information" (www.pubmed.com) and "Scientific Electronic Library Online (www.scielo.br) databases and combinations of key words such as "Prader-Willi-like phenotype" and "Prader-Willi syndrome phenotype". Editorials, letters, reviews, and guidelines were excluded. Articles chosen contained descriptions of patients diagnosed with the PWS phenotype but who were negative for alterations on 15q11-q13. Our search found 643 articles about PWS, but only 14 of these matched with the Prader-Willi-like phenotype and with the selected years of publication (2000-2013). If two or more articles reported the same chromosomal alterations for Prader-Willi-like phenotype, the most recent was chosen. Twelve articles of 14 were case reports and 2 reported series of cases.

A systematic review of the intergenerational aspects and the diverse genetic profiles of Huntington's disease.

Huntington's disease (HD) is a rare progressive and fatal neurogenetic degenerative disease, characterized by movement and personality disorders and by progressive dementia. Its prevalence varies by ethnic origin and different genetic profiles predisposing individuals to HD in each population. The prevalence of HD is 5-10 per 100,000 individuals in Caucasian populations of North America and Western Europe. It is an autosomal dominant disease associated with the expansion of CAG-type repetitive DNA sequences in the HTT gene. This gene, located on the short arm of chromosome 4, encodes the protein huntingtin. In this study, we reviewed 17 articles about HD that report data from 2400 affected individuals from various countries around the world, including Venezuela, China, Croatia, Turkey, Germany, Italy, Brazil, Spain, Taiwan, India, the Netherlands, Russia, and the USA, with a focus on genetic profiles and intergenerational expansions or contractions of expanded alleles responsible for causing HD. We discuss the genetic characteristics of HD in different populations and any atypical cases reported in these studies.

Nylon-6 cylinders and a sponge-like derivative as supports for immobilizing trypsin

1. Two types of nylon-6 supports (small cylinders and a sponge-like derivative) were prepared for immobilizing enzymes. Nylon-6 beads were solubilized by immersion in 80 formic acid and then reprecipitated using two different types of non-solvent solutions (distilled water or a 1:1 acetone:water solution) giving rise to a sponge-like derivative and to a colloidal suspension, respectively. The latter was molded into a thin thread which was cut into small cylinders. 2. Trypsin (EC 3.4.21.4) was covalently bound to glutaraldehyde-activated nylon-6 cylinders as well as to the sponge-like derivative. The maximum (100) apparent initial enzymatic activity was found for the trypsin bound to small cylinders, while the initial activity of trypsin bound to the sponge-like material was 61 in comparison with that of trypsin-small cylinders, under the same conditions of enzyme immobilization reaction (1 g of nylon support and 5 ml of 1.3 mg/ml trypsin in 0.1 M sodium phosphate buffer, pH 8.5, at 10 degrees C for 18 h) and of enzymatic reaction (1 g of trypsin-nylon in a batch reactor, 2 ml of 0.7 w/v azocasein solution in 50 mM borate buffer, pH 8.5, at 37 degrees C, with shaking, for 1 h). However, the decrease of activity after enzyme immobilization was more conspicuous for the trypsin-small cylinders than for the trypsin-sponge. The former retained approximately 25 of its initial activity, while the latter retained approximately 67 of its initial activity, after seven cycles of utilization for 1 h, pH 8.5, at 37 degrees C and 8 days of storage, pH 8.5, at 4 degrees C in the presence of azocasein. 3. Scanning electron microscopy was performed to visualize the surface of the support after each step of the immobilization process. The electron micrographs show that the two types of nylon supports had a rough surface, which became rougher and full of craters after treatment with 5 N HCl. On the other hand, the partially hydrolyzed nylon surface acquired the appearance of Swiss cheese after treatment with 2.5 glutaraldehyde. After reaction with the enzyme molecules the surface became rougher again.