Balearic archipelago: three islands, three beta-thalassemia population patterns.

The mutation spectrum of 175 ß-thalassemia (ß-thal) carriers, identified in pilot carrier screening on 22,713 individuals from Balearic Islands (Spain), is reported. The ß(0) CD39 (C>T) mutation is the most frequent (61.1%), followed by ß(+) IVS-I-110 (G>A) (12.0%), ß(+) IVS-I-6 (T>C) and ß(0) IVS-1-1 (G>A) (3.4% both) and eight other rare mutations (2.9-0.6%); with a distinct prevalence and distribution between islands. Minorca shows the highest prevalence in Iberian populations, with a single mutation, CD39 (C>T), present in most ß-thal carriers. Ibiza is the only Western Mediterranean population where the most frequent ß-thal mutation is IVS-I-110 (G>A). These results can be explained by a combination of historical-demographic characteristics together with evolutionary forces such as founder effect, genetic drift and probably selection by malaria. Knowledge of the mutational spectrum in the Balearic Islands will enable to optimize mutation detection strategy for genetic diagnosis of ß-thal in these islands.

Prevalence of HFE C282Y and H63D in Jewish populations and clinical implications of H63D homozygosity.

The frequencies of C282Y and H63D mutations of the HFE gene vary between different populations. A previous study showed an unexpectedly high H63D frequency in Chuetas (a population of Jewish descent). The present study addressed the question of the distribution of these mutations in Jewish populations from different origins and studied the possible causes of the high H63D frequency in Chuetas. Moreover, to improve the understanding of the controversial relationship between H63D homozygosity and iron overload, a group of patients with altered iron metabolism were studied. The high frequency of H63D mutation in Chuetas is not due to a high prevalence of this mutation in Sephardic Jews. Jewish populations have low C282Y and moderate H63D frequencies, suggesting slight gene flow from their surrounding populations. In accordance with historical and demographic data, genetic drift is the most probable cause for the singular H63D frequency in Chuetas. Clinically, this study of H63D homozygotes supports the conclusion that this genotype must be taken into account, because it confers an increased risk of iron overload and therefore genetic susceptibility to developing hereditary hemochromatosis or to aggravating other diseases.

Pre-exercise antioxidant enzyme activities determine the antioxidant enzyme erythrocyte response to exercise.

Free radical production increases during exercise and oxidative damage occurs in several tissues. We examined the effects of three different exercise tests on the pattern of change of erythrocyte enzyme antioxidant activities. The tests were a short maximal exercise test, a submaximal prolonged exercise test and a cycling stage during competition. The participants were amateur and professional cyclists with different training statuses and different basal erythrocyte antioxidant enzyme activities. The maximal test produced no changes in the erythrocyte antioxidant enzyme activities of amateur sportsmen. The submaximal test, performed at 80% of maximal oxygen uptake, decreased erythrocyte catalase (12%), glutathione peroxidase determined with H2O2 (14%) and glutathione reductase (16%); superoxide dismutase activity increased by about 25%. The cycling stage performed by professional cyclists increased erythrocyte catalase (29%) and glutathione reductase (10%) activities. The in vivo changes in glutathione reductase activity were confirmed by in vitro measurements: hydrogen peroxide decreased and the presence of catalase increased the activity of this enzyme. In conclusion, we suggest that the different erythrocyte antioxidant enzyme responses to diverse exercise tests can be explained by the effects of hydrogen peroxide and the superoxide anion on the antioxidant enzyme activities in erythrocytes.

Distribution of HFE C282Y and H63D mutations in the Balearic Islands (NE Spain).

The HFE gene contains two main missense mutations: C282Y and H63D. Individuals with these mutations carry a risk of developing hereditary haemochromatosis (HH). The common form of this disease is due to homozygosity for the C282Y mutation. Population studies have shown the variation of the prevalence of these mutations in different countries and ethnic groups. The purposes of this current study were to determine the prevalence of the C282Y and H63D mutations in the Balearic Islands and the genotypic characterization of patients diagnosed with HH, as well as those with iron overload and liver diseases. A total of 1330 Balearic chromosomes were analyzed. The results showed that the populations of the Balearic Islands were not homogeneous. No C282Y carriers were observed in a group of descendants of Majorcan Jews (Chuetas) and the frequency was very low in Minorca (1.2%) in comparison with the other islands of Majorca (4.7%) and Ibiza (6.5%). The carrier frequency of the H63D mutation was similar in the three islands and very high (43.1%) in the descendants of Majorcan Jews. The study of patients was carried out in 129 individuals. The homozygous C282Y genotype was the principal one involved in hereditary haemochromatosis (90%), whereas the other HH patients were C282Y/H63D compound heterozygous and H63D homozygous.

Prevalence of the C282Y mutation for haemochromatosis on the Island of Majorca.

The C282Y mutation of the HFE gene has been reported to be present in most of the patients with hereditary haemochromatosis (HH) of Northern European ancestry. HH affects approximately 1/300 individuals, but it is not evenly distributed in the different European countries. In the present study, polymerase chain reaction (PCR) and restriction-enzyme digestion were used to analyse the frequency of the most important mutation in haemochromatosis (C282Y) in subjects from Majorca (Balearic Islands, Spain) and patients with haemochromatosis. The results were compared with other studies from Spain and Europe. A total of 420 Majorcan chromosomes were analysed and the C282Y mutation was observed at a frequency of 2.62%+/-0.8 (11 heterozygotes: eight men and three women). In the group of hereditary haemochromatosis probands, 13 out of 14 were homozygous for the C282Y mutation. In the distribution of the C282Y mutation, a north-west to south-east cline was detected, supporting the Celtic origin of this mutation.

[Comparative study of the analyzers L-9100 (Merck-Hitachi) and HA-8121 (Menarini) for the determination of glycosylated hemoglobin]. / Estudio comparativo de los analizadores L-9100 (Merck-Hitachi) y HA-8121 (Menarini) para la determinación de hemoglobina glucosilada.

A comparison study about the determination of HbA1c by L-9100 (Merck Hitachi) and HA-8121 (Menarini) was made. HbA1c was measured by high pressure liquid chromatography (HPLC). The within-run imprecision was CV < 3% (for HA-8121) and CV < 4.9% (for L-9100). The between-run imprecision was CV < 1% (for L-9100) and CV < 2% (for HA-121). Analysis of means (Student test) showed that both instruments were statistically different for HbA1Ac measurements (p < 0.001). The results of regression analysis (Passsing-Bablock test) were as follows: y = 0.88x + 0.58 (y = L-9100, r = 0.982, p = 0.005). In conclusion, the results showed that there are statistical differences between both instruments. Regression and correlation was good, but the data also showed that there is a constant and proportional error. We must make a new reference range values.