We have analysed the alpha-globin gene defects present in several members of a large family from Southern Turkey. One deletional alpha-thalassaemia-1 (type MED-II) was found in 10 subjects: this deletion is in excess of 26.5 kb and includes all zeta- and alpha-globin genes. Besides the common types of deletional alpha-thalassaemia-2 (-3.7 kb and -4.2 kb) we observed a nondeletional alpha-thalassaemia-2 that results from an A----G mutation (AATAAA----AATGAA) in the polyadenylation signal of the alpha 2-globin gene: the same A----G replacement is present in the psi alpha l gene. The mutation must cause a considerable alpha-chain deficiency as is evidenced by the haematological data for five members with Hb H disease due to a compound heterozygosity for alpha-thalassaemia-1 (MED-II) and the newly discovered poly A mutation. Several members had additional beta-chain abnormalities (Hb S, Hb D-Los Angeles, beta-thalassaemia); the 11 persons with a Hb S heterozygosity and various alpha-globin gene defects (-alpha/alpha alpha; alpha T alpha/alpha alpha, - -/alpha alpha, -alpha/-alpha and - -/alpha T alpha) showed a decrease in the level of Hb S that was directly related to the severity of the alpha-chain deficiency.

SUMMARY. The analytical, intra-individual, inter-individual variation and reference values were determined for red cell glucose-6-phosphate dehydrogenase (G6PD). Different procedures for the conditions for storage of red blood cells and the preparation of haemolysates were investigated.A total of 2170 samples of blood were taken from apparently healthy persons-1212 males and 958 females-from randomly selected villages and city centres in the southern part of Turkey. Analytical variation, intra-individual variation and inter-individual variation were 8· 67%, 32· 8% and 31' 8070, respectively. The mean (SD) for G6PD was 8·6 (3' 3) IU/gHb. The index of individuality, 1,03, showed that the reference intervals could be used for diagnostic purposes.Whole blood or a red cell pellet could be stored in physiological saline for one week at 4°C or -20°with little loss of activity. Two of three different procedures for the preparation of haemolysate gave data that showed no statistical difference and were equally satisfactory.

Hemoglobinopathies are the most common genetic diseases in Turkey. The incidence of sickle cell trait is 10.0% and beta-thalassemia (beta-thal) trait is 3.7% in the Cukurova region of southern Turkey. Sickle cell anemia is prevalent in the Cukurova region, but beta-thal is seen all over the country. A prenatal diagnosis center was established in 1992 at Adana, Turkey, for the prevention of sickle cell anemia and beta-thal. Fifteen hundred and seventy-five fetuses were examined at the Cukurova University Hospital, Adana, Turkey. Three hundred and eighty-six fetuses were diagnosed as homozygous or compound heterozygous for sickle cell anemia and beta-thal. A total of 15 different beta-thal mutations were characterized in the parents. The incidence of the IVS-I-110 (G > A) mutation accounted for about 50.0% of the parents with beta-thal trait. Twenty-four different genotypes were observed in this study. A total of 286 fetuses were diagnosed with homozygous sickle cell disease, 57 fetuses were beta-thal homozygotes, 25 fetuses were compound heterozygotes with Hb S [beta6(A3)Glu-->Val, GAG > GTG], and 18 of the fetuses were double heterozygotes for beta-thal mutations.

Beta-thalassemia is the most common genetic abnormality causing health problems worldwide. Cukurova, in the southern part of Turkey, being on the Mediterranean, is in the thalassemic belt. Since there is no cure for the disease at present, the frequency of the mutation types of beta-thalassemia must first be identified to aid in clinical follow-up and prenatal diagnosis. Carriers identified during a screening survey and patients referred to our laboratory were studied for this purpose. After routine hematological analysis molecular screening was performed by the amplification refractory mutation system and DNA sequencing. The frequency of the common mutations were: IVS-I-110 (G-->A) 57.3%, IVS-I-1 (G-->A) 8.3%, codon 39 (C-->T) 6.4%, IVS-I-6 (T-->C) 5.7%, frameshift codon 8 (-AA) 5.7%, -30 (T-->A) 4.7%, IVS-II-1 (G-->A) 3.4%, IVS-II-745 (G-->C) 2.8%, and frameshift codon 5 (-CT) 1.1%. Some rare mutations (1%) such as frameshift codon 44 (-C) 0.7%, frameshift codons 74/75 (-C) 0.7%, IVS-1-5 (G-->C) 0.7%, frameshift codons 8/9 (+G) 0.4%, frameshift codons 36/37 (-T) 0.4%, frameshift codons 22/23/24 (-AAGTTGG) 0.4%, IVS-1-130 (G-->C) 0.4%, IVS-1-5 (G-->T) 0.2%, -28 (A-->C) 0.2%, codon 15 (TGG-->TGA) 0.2%, and frameshift codons 82/83 (-G) 0.2%, were detected by sequence analysis. The codon 15 (TGG-->TGA) and frameshift codons 82/83 (-G) mutations were seen in Turkey for the first time.

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