Four categories of gamma-globin gene triplications: DNA sequence comparison of low G gamma and high G gamma triplications.

The human fetal gamma chains are produced by closely linked G gamma and A gamma genes, and unequal crossing over between them leads to gamma gene deletions and triplications. Nine gamma gene triplications from seven ethnic groups were analyzed for G gamma and hemoglobin F (Hb F) values of heterozygotes and for the presence of polymorphic XmnI restriction sites 5' to the gamma genes. Four categories of triplication were found: I had low G gamma and low Hb F values and lacked XmnI sites 5' to the three gamma genes [---]. II had high G gamma and slightly elevated Hb F values but was also [---]. III was similar to II, except that XmnI was [+--]. IV had very high G gamma and slightly elevated Hb F values, and XmnI was [++-]. One case each of triplications I and IV were cloned into Charon 35. For both, the two 5' gamma gene code for G gamma chain, while the 3' gamma gene codes for A gamma chain. DNA sequencing showed that the unequal crossover occurred between 472 and 398 base pairs (bp) 5' to the gamma gene Cap sites (-472 and -398) for the type IV triplication and between -271 and codon 136 for the type I triplication. In addition, type I had a 4-bp deletion of AGCA from -225 to -222. The high G gamma values of the type IV triplication are explained by its -G gamma-G gamma-A gamma-gene arrangement and the XmnI sites 5' to the G gamma genes. We hypothesize that the low G gamma value of the type I triplication, which is also -G gamma-G gamma-A gamma-, is due to inactivation of the middle G gamma gene by the AGCA deletion at -225 to -222.

The 18- to 23-kb deletion of the Macedonian delta beta-thalassemia includes the entire delta and beta globin genes.

Restriction endonuclease mapping analyses were made of DNA from a few members of a Macedonian family with hematological characteristics of delta beta-thalassemia, ie, microcytosis, normal HbA2 levels, and elevated levels of HbF (7% to 14%) with G gamma (average 40.5%) and A gamma T chains (average 59.5%). A large deletion of 18 to 23 kb was present with a 5' breakpoint within a 670-bp segment of DNA between the HpaI and NcoI restriction sites 5' to the delta globin gene, and a 3' breakpoint between the BamHI and HpaI restriction sites located some 9 to 13 kb 3' to the beta globin gene. This deletion is different from those present in other types of G gamma A gamma(delta beta)zero-thalassemia. The similarity of the hematological expression of these delta beta-thalassemic conditions which have somewhat comparable 5' breakpoints supports the idea that an important fetal hemoglobin-controlling region lies between the psi beta and delta globin genes.

Sickle cell anaemia among Eti-Turks: haematological, clinical and genetic observations.

Haematological and genetic observations have been made on 71 SS Eti-Turk patients and their relatives from Cukurova (southern Turkey) and of immigrant families in The Netherlands. Similar data were collected for 25 Black patients and their relatives from Surinam, Netherlands Antilles, and Kenya. Haematological and clinical results were the same for both groups; the haemolytic anaemia in the Turkish patients was as severe as in the others. Haplotyping, involving nine restriction sites, identified haplotype 19 (Antonarakis et al, 1984) as the major type among the Eti-Turks; this chromosome has previously primarily been observed among SS patients from West Africa. The suggestion that the beta S-chromosome among Eti-Turks originates from that area is supported by a relatively high incidence of alpha-thalassaemia-2 (the 3.7 kb deletion), also frequently present in the Black population of West Africa, and by the absence of other major haplotypes, such as types 20 and 3, characteristic for the beta S-chromosome in the population of Central Africa and Kenya, and in Senegal, respectively. The Saudi Arabian type of beta S chromosome in association with the haplotype 19 beta S chromosome was present in only one Eti-Turk patient; this 30-year-old female was mildly affected and exhibited a high level of fetal haemoglobin.

G gamma A gamma(delta beta)zero-thalassaemia and a new form of gamma globin gene triplication identified in the Yugoslavian population.

Among several hundred apparently healthy Yugoslavian adults with slightly elevated levels of fetal haemoglobin, we have identified two distinct abnormalities. (a) A G gamma A gamma(delta beta)0-thalassaemia heterozygosity with an approximately 15 kb deletion which involves part of the delta globin gene and the beta globin gene. This deletion is probably the same as that seen among Italians (Ottolenghi et al, 1982; Carè et al, 1984). (b) A nondeletion form of hereditary persistence of Hb F which is caused by a gamma globin gene triplication of the (+)G gamma.(+)G gamma.A gamma type. It is characterized by the presence of some 5% Hb F in the heterozygote containing nearly 100% G gamma chains. The C----T mutation at position--158 5' to the G gamma chain [(+)G gamma], identified through analyses of Xmn I digests, was present at both G gamma globin genes. This mutation is known to be associated with increased G gamma chain production (Gilman & Huisman, 1985), and thus is responsible for the increased G gamma chain production in these heterozygotes. The condition is different from the (+)G gamma.(+)G gamma nondeletion type of HPFH which has been observed in heterozygotes of two Black families, and is associated with the presence of 3-4% Hb F (with mainly G gamma chains) in heterozygotes.

Five adults with mild sickle cell anemia share a beta S chromosome with the same haplotype.

Five adult SS patients from Qatar, Turkey, and South Africa with mild disease, had greatly elevated Hb F and specific patterns of polymorphic sites on their beta S chromosomes. One subject had an alpha-thalassemia (-alpha/-alpha). The haplotypes were the common type #19, associated with severe disease, and type #31, not seen thus far in an SS patient (numbering system of Antonarakis et al). The data suggest that modifications in the DNA of the beta S #31 chromosome promotes the synthesis of gamma chains.

Hematological observations on Arabian SS patients with a homozygosity or heterozygosity for a beta S chromosome with haplotype #31.

Hematological and hemoglobin composition data are presented for seven Arabian SS patients with mild disease and with high Hb F levels varying between 21 and 34%. Four patients were homozygous for a beta S chromosome with a specific haplotype (#31). The data for these four patients were similar to those for three other SS patients (and for five patients reported earlier, Ref. 2) who were heterozygous for the same beta S chromosome (#31) and for a beta S chromosome with another haplotype (mainly #19). These data offer additional evidence indicating that the increased gamma chain production is specific for the beta S chromosome with haplotype #31. The similarities in hematological data and Hb F levels between these two groups of SS patients and the normal Hb F value in Hb S heterozygotes with beta S chromosome (#31) support the suggestion that the increased Hb F production mainly occurs in response to the anemia of the sickle cell disease.

Aplastic anemia due to chemicals and drugs: a study of 108 patients.

To illustrate the etiologic role of drugs and chemicals in the development of aplastic anemia, we analyzed 108 cases of aplastic anemia among 3,715 hematologic patients during a ten-year period at the hematology section of Istanbul Medical School. Among these 3,715 patients, 695 had leukemia, a result indicating the relative rarity of aplastic anemia as compared with leukemia. Of the 108 patients, 58.3% were male and 41.7% were female. Their ages ranged from six months to 82 years. Pancytopenia was severe in 42.6% of the patients, and moderate or mild in 57.4%. Bone marrow was hypocellular in 84 patients, normocellular in 16, and hypercellular in eight. In 52 (48.1%) of the patients with aplastic anemia, the following etiologic factors were implicated: benzene (25 patients), antirheumatic drugs (ten), chloramphenicol (four), chloramphenicol plus hepatitis or chromosome anomalies (two), thiamphenicol plus sulfonamide (one), antituberculous drugs (three), daraprim (three), insecticides (two), hepatitis (one), and sulfonamide (one). Data indicate that the degree of bone-marrow cellularity is not always related to functional capacity, and numerous agents may have etiologic roles in the development of aplastic anemia.

A comparison of two procedures useful for the isolation of Hb F from adult red blood cells and for the quantitation of the types of gamma chain by high-performance liquid chromatography.

Two methods have been used to isolate Hb F from red cells with low levels of Hb F (less than 2% FAD), namely an alkali denaturation procedure, as described by Tsuchiya et al. [Dokkyo J. Med. Sci., 10 (1983) 13], and anion-exchange chromatography. Analyses of these Hb F enriched hemoglobin solutions by high-performance liquid chromatography allowed quantitation of the different gamma chains in the Hb F. Although the data showed considerable variation, particularly for samples with low levels of Hb F, the final results obtained with the two approaches were comparable, suggesting that the much simpler and more economical alkali denaturation procedure can be used for this purpose.

Clinical observations showing the role of some factors in the etiology of multiple myeloma. A study in 7 patients.

7 cases of multiple myeloma with a history of exposure to benzene, radioactive iodine, chemotherapy for Hodgkin's disease and of repeated injections of autovaccine to Staphylococcus albus hemolyticus are described. The relationship between the development of multiple myeloma and possible etiologic factors is discussed.

Endometrial cancer due to busulfan therapy. Report of two cases.

Two patients with CML who developed endometrial cancer following 2 years of busulfan treatment are reported. The possibility of a causal relationship between the cytotoxic drug and the development of this malignancy is discussed.