Ida Bianco

Factors regulating Hb F synthesis in thalassemic diseases

BackgroundThe thalassemic syndromes originate from mutations of the globin genes that cause, besides the characteristic clinical picture, also an increased Hb F amount. It is not yet clear if there are more factors, besides the beta globin genotype, determining the Hb F production. We have tried to find out if there are relations between total Hb and Hb F, between erythropoietin (Epo) and Hb F, between Hb F and point mutations of the gamma gene promoters.Materials and MethodsHematologic parameters, iron status, alpha/non-alpha globin ratio, Epo level, and thalassemic defects of the alpha-, beta-, and gamma-globin genes were explored using standard methods in patients affected by thalassemic diseases. Ninety-five non thalassemic individuals have been examined as controls.ResultsTwo clinical variants of beta-thalassemia intermedia referred to as beta-thal int sub-silent and evident are associated with distinct sets of mutations of the beta-globin gene. Silent beta thal mutations are invariably associated with sub-silent beta thal int; beta° or severe beta+ thal mutations are associated with evident beta thal int (88%) and almost invariably (98%) with thalassemia major. A positive correlation was observed between the severity of the disease and the Hb F level, but no correlation was found between the Hb F and erythropoietin (Epo) level. The mutation Ggamma -158 C→T was detected in 26.9% of patients affected by beta-thal int sub-silent and evident, respectively, but only in 2% of patients with thalassemia major.ConclusionsThe severity of beta-thal int and the increased Hb F level are strictly dependent from the type of beta-globin gene mutations. No relation is found between Hb F synthesis and Epo secretion. The mutation Ggamma -158 C→T, common among patients affected by beta-thal int and very rare in thal major patients, does not seem, in this study, to influence the Hb F content in beta thal int patients.

Genetic Patterns in Thalassemia Intermedia (Constitutional Microcytic Anemia)

Globin chain synthesis has been studied in 17 patients with thalassemia intermedia, and their relatives, also investigated by routine hematologic and hemoglobinic tests. The mean a/non a ratio was always around 2.20-2.30. In patients with severe thalassemia major, used as a control, the mean a/non a ratio was significantly higher, that is 3.11-3.07. Therefore, the hypothesis that the cause of the lesser severity of the thalassemia intermedia is a lesser imbalance of globin chain synthesis, is suggested. One or both the parents of patients with thalassemia intermedia have mild beta-thalassemia and normal alpha/beta ratio, whereas the parents of patients with severe thalassemia major show a marked beta-thalassemia and a mean alpha/beta ration of 1.76. These data suggest that genes for beta +-thalassemia are responsible for thalassemia intermedia, and genes for beta o-thalassemia are responsible for thalassemia major. In two patients with thalassemia intermedia, the association of an alpha-thalassemia gene with homozygous beta-thalassemia that it is well known to reduce the globin chain imbalance typical of the beta-thalassemia, has also been observed.

A screening programme for the prospective prevention of Mediterranean anaemia in Latium: results of seven years' work

Since 1975 the Rome Microcythaemia Centre has carried out every year, under the auspices of the health authorities of the Latium region, a screening of thalassaemics among intermediate schoolchildren of Latium. From these campaigns, knowledge about thalassaemias among the young adult population has grown which, in its turn, has resulted in screening of these young adults. Through screening in schools between 1975 and 1982, of 289 763 students examined, 6838 thalassaemics were identified, 6045 of whom were beta- or delta beta-thalassaemics. The total number of young thalassaemics who are identified at present in the Centre through screenings of schoolchildren and young adults is about 3300 per year. Furthermore, from January 1980 to April 1983, 110 prospective couples of child-bearing age at risk (94 of whom originated from Latium) were identified at the Centre, and five homozygous fetuses (three of which originated from Latium) were diagnosed. These data derive from an area in which the frequency of thalassaemia is only 2.4%, and they show that the programme in Latium for the prevention of Mediterranean anaemia has been successful.

Screening of thalassaemia carriers in intermediate school of Latium: results of four years' work.

From 1975 to 1979 the Rome Microcythaemia Centre carried out four health education campaigns and thalassaemia screenings among students of the intermediate schools throughout Latium, under the auspices and with the financial support of the Health Authorities of the Latium region. This project is aimed at avoiding reproduction by pairs of thalassaemia carriers and the birth of homozygous children. During the four campaigns 138 501 students were examined, that is, 70 to 76% of those enrolled. Of these 3343 were found to be thalassaemic. Thus the overall prevalence of thalassaemia in Latium is 2.41%, with minor fluctuations from one province to another and, above all, a slight, though definite, trend towards higher values in the southern part of Latium bordering on Campania. The screening was welcomed by the population and the thalassaemic families, there were no detectable negative side-effects, and it resulted in an increased awareness of the problem of the thalassaemias.

First premarital screening of thalassaemia carriers in intermediate schools in Latium.

In the 1975 to 1976 school year, under the auspices of the Health Authorities of the Latium Region, the Rome Microcythaemia Centre carried out for the first time a partial screening survey of thalassaemia carriers among the students of the compulsory intermediate school in Latium. This work was the beginning of a new preventive school health service aimed at the prophylaxis of Cooleys disease. In 23 places investigated in Latium, 17724 students were examined, 13354 of whom were in Rome and 4370 elsewhere. The mean percentage of co-operation was 70% and the mean percentage of thalassaemia 2.42%. Thalassaemic students were invited to attend the centre for a check-up along with their families: about half had already come in by the end of June 1976. All students examined, whether normal or thalassaemic, have received written results of the tests. The screening survey aroused notable interest and obtained wide approval both at school and at home. The news of being thalassaemia carriers, even if not welcome, was never the cause of family tragedy.

Detection of a Rare β-Globin Nonsense Mutation [Codon 59 (AAG→TAG)] in an Italian Family

In this study we report on the hematological and molecular findings of a family from Central Italy, whose 33-year-old male proband presented with a β0-thalassemia (thal) trait associated to a relevant Hb F level. The proband and his family (parents and a sister) were investigated by hematological analysis. The two β-thal carriers of the β-globin nonsense mutation [codon 59 (AAG→TAG)] (the proband and his father) showed the hematological picture of a β0-thal trait: the only hematological difference between the two β-thal carriers was in the Hb F level (3.3% in the proband and 1% in his father).

Heterozygous β-Thalassaemia with Normal Haemoglobin Pattern

Thalassaemia with normal levels of Hb A, and Hb F and with an α/β ratio higher than 1 is described in 4 families. 3 of these families show direct or indirect signs of the presence of the δ-thalassaemia gene along with the β-thalassaemia gene. The fourth family leaves the question as to whether there is a single mutation of the δβ tract or a β + δ-thalassaemia in coupling unanswered. The necessity of knowing of the existence of this thalassaemia which conceals the presence of a β-thalassaemia gene, is stressed, above all in view of the danger that mating between a carrier of this thalassaemia and a carrier of classical β-thalassaemia could result in the birth of children with Cooley’s disease.

The Haemoglobin Picture in Cooley's Disease

Summary The haemoglobin picture has been studied in 38 patients with Cooleys anaemia, all homozygous for β‐microcythaemia. In 10 of the patients Hb A1 was completely absent, in the remaindcr it was present on agar gel electrophoresis in amounts varying from minute traces to a rather abundant quota.

Data for the study of linkage in man: microcythaemia and the Lewis-Secretor characters.

The investigation reported in the present paper is part of a large research programme, undertaken in order to discover whether linkage relationships exist between the locus for the gene ‘M’ and any of the loci for the blood-group genes. The gene ‘ M ’ is autosomal and is responsible, in heterozygous condition (Mm) for a mild and generally asymptomatic anaemia (microcythaemia or thalassaemia minor) and, in homozygous condition (MM), for a severe disease leading to death in childhood (thalassaemia major or Cooley’s disease). The genetics of thalassaemia have been extensively studied in the la& ten years, mainly in Italy and in America. Full details and bibliographic references are given in recent reviews by Silvestroni (1949), Nee1 (1950), Bianco, Montalenti, Silvestroni & Siniscalco (1952) andMontalenti (1953). The gene ‘M’ has a distribution practically limited to the Mediterranean area, with a highest incidence in Greece and in some regions of northern Italy. In the district of Ferrara (Italy) the frequency of heterozygotes may be as high as 18 % (Silvestroni & Bianco, 1952). The samples of blood from the thalassaemic families were tested for the following blood-group systems: ABO, M N S , Rh, P, Lutheran, Duffy, Kell, Lewis and the Secretor character associated with the Lewis blood group. A full account of this material will be published later; only the results concerning the Lewis and Secretor are given here because these seem to be the only ones in which there is any likelihood of a linkage with thalassaemia. Specimens of blood from 203 families were collected during the summer of 1952 in the district around Ferrara. These families were selected by the presence of at least one microcythaemic parent. Each family was tested as completely as possible for all the above blood-group systems within 24 hr. of collection. Since, for practical reasons, it was not possible to perform all the blood-group determinations in every case, the total number of families tested was usually slightly different for each comparison. In the first instance the search for linkage was performed without paying any attentior! to the well-known relationships (Grubb, 1948; Grubb & Morgan, 1949; Race & Sanger, 1950) between Lewis and Secretor as if we were dealing with two different loci. This seemed to be convenient because-as many authors have recently pointed out, mainly Grubb (1951) and Ceppellini (1953)-there is still a great deal of controversy about the exact nature of those relationships.

Updated results of the thalassaemia prevention programme carried out in Latium.

Previous results of our programme have been published in this Journal. 1-3 Its basic concept is that both the distribution of information about the prevention of Mediterranean anaemia (thalassaemia) and the mass screening for thalassaemia carriers must be carried out much earlier than adulthood and must not be exclusively aimed at pregnant women or already established couples. Early timing of the preventive actions now available provides thalassaemia carriers with a number of options for prevention (including the choice of a non-thalassaemia carrier partner) besides making the option of selective abortion earlier, easier, and more widely adopted. Based on these grounds, the preventive programme carried out in Latium from 1975 by the Centro di Studi della Microcitemia di Roma, supported by Regional Health Authorities of Latium, consists of the following.