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.

[Review of infectious prophylaxis in splenectomized patients in the island of Menorca]. / Revisión de la profilaxis infecciosa en pacientes esplenectomizados en la isla de Menorca.

BACKGROUND: Splenectomized patients are at higher risk of severe infection. PATIENTS AND METHOD: This retrospective study was performed to evaluate compliance with guidelines in patients who underwent a splenectomy between 1978 and 2000. Seventy-five patients were identified and their hospital records were reviewed. RESULTS: 62.7% of patients who had a splenectomy received a pneumococcal vaccine and were aware of the infectious risks related to an asplenic status. CONCLUSIONS: Rapidly lethal overwhelming sepsis in some asplenic patients demands greater prevention efforts by physicians.

[Campaign for the detection of minor beta-thalassemia and prevention of major beta-thalassemia in the isle of Menorca. 10-year experience]. / Campaña para la detección de la betatalasemia minor y prevención de la major en la isla de Menorca. Experiencia de 10 años.

BACKGROUND: The high prevalence of betathalassemia minor and the presence of several cases of thalassemia major in Menorca (Spain) led us, ten years ago, to set up a population based prevention campaign, following the basic schedule of those already taking place in other areas, specially in Italy. PATIENTS AND METHODS: The target population was the children in the last year of mandatory school, when they are 13 to 14 years old. The campaign started in the school year 1986-1987 and in the 1995-1996 course we reached the tenth yearly campaign. The campaign was structured in three stages: the first one included all information and educational aspects; the second step corresponded to blood sampling and detection of carriers; finally, results were reported to the individuals and genetic counseling was given. For evaluation purposes, we have monitored participation rates, the proportion of detected carriers which present to haematology visit and the trend in the proportion of carriers which previously knew their status. RESULTS: A total of 8,591 children were screened, accounting for a 83.8% participation rate. The observed prevalence was 26.7/1000 (95% CI, 23.5-29.9/1000). We also detected 9 cases of alfathalassemia and 4 cases of deltabetathalassemia. CONCLUSIONS: Our results show that participation rates may be reached through school screening campaigns for thalassemia. After ten years of campaign, the number of not previously known cases has become small, indicating that the campaign screening to relatives of detected carriers and a higher consciousness level in the general population have given the expected effect. In the last 14 years, not a single homozigote case has been born, although we cannot conclude that this has been only due to the campaign.

[Prevalence of glucose-6-phosphate dehydrogenase deficiency in a student population on the island of Menorca]. / Prevalencia del déficit de glucosa-6-fosfato deshidrogenasa (G6PD) en la población escolar de la isla de Menorca.

BACKGROUND: The G6PD deficiency is a red cell enzymopathy very frequent in certain Mediterranean countries. In Menorca (Balearic Islands), a relatively high incidence of favism carried us to study the prevalence of this alteration, taking advantage of the "Campaign for detection of heterozygous beta-thalassaemia to prevent the homozygous beta-thalassaemia" that we make annually. METHODS: We studied a total of 1139 school boys between 13-14 years old for three consecutive school years. We used the methylene blue as screening test and the deficiency of G6PD was confirmed with enzymatic quantification in the haemolysate. We also analysed the clinical manifestations and studied the relatives. RESULTS: We have confirmed 11 cases of G6PD deficiency (prevalence of 9.7/1000), all of them native of the island. The clinical manifestations were: in 6 cases (54.5%) no clinical manifestations were found, 5 cases (45.4%) had presented neonatal jaundice and 2 cases (18.2%) had suffered a favism crisis. The study of relatives permitted us to analyse 26 additional samples (17 women and 9 men), detecting in 8 of them (4 women and 4 men) the enzymopathy . CONCLUSIONS: The prevalence of G6PD deficiency in Menorca is one of the highest in Spain. Most of the carriers are asymptomatic, the most important clinical manifestations being the neonatal jaundice and favism. The screening test used is efficient for unmistakable hemizygotes detection.

[A campaign for detection of beta-thalassemia minor and prevention of beta-thalassemia major in the island of Minorca. 2 years' experience]. / Campaña para la detección de la betatalasemia minor y prevención de la major en la isla de Menorca. Experiencia de dos años.

The high prevalence of beta-thalassemia minor and the occurrence of thalassemia major in Minorca prompted us to develop a prevention campaign. The selected population consisted of primary school students. The campaign was operative during the terms 1986-87 and 1987-88 and had three stages: 1.) informative; 2.) analytical study and diagnosis of carriers; 3.) report of the results and genetic counselling. We studied overall 1862 schoolchildren. The prevalence of beta-thalassemia minor was 3.38%. We discuss the methodology, the results and the effectiveness of the campaign.