The gamma-chain in a Ghanain homozygous for hereditary persistence of fetal haemoglobin was considered to be of the Ggamma type on the basis of the amino acid analysis of gammaTp XIV (gamma133-144) of the Hb F of this subject [1]. Recently, the sequence of residues gamma134-137 of the gamma-chain of this subject was determined and found to contain some alanine at position gamma136. It is therefore of the Ggamma + Agamma type. A rapid technique for the isolation of gammaCB-3 (gamma134-146) peptides in human fetal haemoglobin for Ggamma:Agamma ratio determination is described.

Three Negro kindreds with hereditary persistence of fetal hemoglobin (HPFH) alone and in combination with various other hemoglobin abnormalities including beta thalassemia are presented. Among 11 offspring of two women heterozygous for both HPFH and the delta chain mutation Hb B2, five inherited the HPFH gene and six inherited the Hb B2 gene. In another kindred, a man inferred to be heterozygous for both HPFH and Hb C had six children; three offsprivg obtained the Hb C gene and three the HPFH gene. Similarly, a woman heterozygous for both Hb S and HPFH transmitted the Hb S gene to one of her two children and the HPFH gene to the other. Thus among 19 offspring, no crossovers between the HPFH locus or the Hb delta-beta locus were observed. These and earlier data are compatible with deletion of the Hb beta and delta loci as the primary event to explain the genetic origin of HPFH. Genetic considerations indicate that the finding of a single person with a hematologically normal phenotype among offspring of heterozygotes for both the African type of HPFH and a Hb beta or Hb delta structural abnormality would invalidate the deletion model.

Two dimensional gel analysis of skeletal muscles from normal pigs and from pigs which were homozygous for halothane sensitivity showed no obvious differences in the patterns of spots attributed to the major contractile proteins and glycolytic enzymes. In muscle from a sensitive pig which died of heat shock under anaesthesia there was a selective loss of glyceraldehyde-3-phosphate dehydrogenase and aldolase, presumably owing to proteolytic activity. The progressive loss of these enzymes under anaesthesia could contribute to the mechanism of heat production by diverting fructose 1,6 diphosphate into a futile cycle.

Malignant hyperthermia occurs in man and pigs as a hereditary disorder notably as a complication of halothane-induced anaesthesia. It involves an abnormality in the metabolism of Ca2+. A search was made for abnormalities of calcium-binding proteins. Troponin C from normal pig muscle was found to differ in 2 of 159 amino acids from rabbit Tn C and 3 from man. No differences between normal and abnormal pig muscle were found. Two-dimensional electrophoresis of red cell calmodulin from normal and abnormal pigs also failed to demonstrate a difference.

Hereditary Persistence of Fetal Hemoglobin (HPFH) is a benign clinical condition characterized by the synthesis of HbF and which continues without hematological alterations during adult life. Since the function of HPFH in many hemoglobinopathies is that of a severity modulator, it is important to learn its frequency. To obtain this information, a study was conducted on 1,846 blood donors from Bragança Paulista, São Paulo State. Hemoglobin was qualitatively analyzed by hemolytic electrophoresis on agarose gel. Qualitative analysis of gammaG and gammaA chains was performed by electrophoresis in polyacrylamide-triton-urea. Two individuals were found to have a high fetal index (0.1%). The percentage of FHb in one individual was 17% and in the other 18%. The gamma G chain was missing in both electrophoretic chains. Cases screened according to laboratory characteristics were of the pancellular hereditary persistence type due to mutation. The frequency in this sample was thus 1/1,000 individuals.

Nd-HPFH are haematological conditions which are natural models to aid understanding of the haemoglobin (Hb) switch. In this paper we describe a new non-deletional hereditary persistence of fetal haemoglobin (nd-HPFH) associated with the highest Hb F level observed to date (up to 49% without haemopoietic stress). Sequence of the G gamma promoter revealed a cytidine insertion within a stretch of four cytidines, located between -200 and -203 bp with respect to the cap site. This insertion is situated within a polypyrimidine-polypurine region which can adopt a triple helix structure, and is therefore of particular interest with respect to the Hb switch mechanism.

Hereditary persistence of fetal hemoglobin (HPFH) has typically been ascribed to mutations in the beta-globin gene cluster. Pharmacologic agents, including the short-chain fatty acid butyrate, have been shown to upregulate fetal and embryonic globin gene expression. In this report we investigate the possibility that metabolic derangements characterized by an inability to metabolize another short-chain fatty acid, propionate, could be associated with a persistence of fetal hemoglobin unrelated to alterations in the beta-globin cluster. Embryonic globin gene upregulation in a murine adult erythroid cell culture was shown by RNase protection after induction with three short-chain fatty acids (C2-C5). Chart reviews and measurement of fetal hemoglobin in five patients with abnormalities in propionate (C3) metabolism were undertaken; SSCP/dideoxy fingerprint analysis of the gamma-globin gene promoters was done in three of these five patients. Twelve patients with other metabolic derangements served as controls. Only the four patients with clinically severe abnormalities in propionate metabolism (ages 2 to 11), but without anemia, showed a sustained elevation in fetal hemoglobin (3% to 10%). The level of elevation of fetal hemoglobin in these patients, who lack erythropoietic stress, suggests that propionic acid and/or its metabolites are potent stimulators of fetal hemoglobin expression. Study of this group of patients should allow unique insights into the long-term effects of sustained exposure to elevations of short-chain fatty acid levels.

During human development there is a switch from fetal to adult haemoglobin formation, reflecting the differential expression of fetal (G gamma and A gamma) and adult (beta and delta) globin genes. Mutations that inhibit this switch produce variants of the syndrome of hereditary persistence of fetal haemoglobin (HPFH). Adult heterozygotes for these mutants produce 15-30% fetal haemoglobin (HbF) in their red cells. The general assumption is that the mutations result in a permanent switching on of gamma-globin genes. Here, however, we show that fetal globin expression can be turned off in cultures of HPFH cells by an uncharacterized factor in fetal sheep serum. This is the first demonstration that mutations affecting the developmental expression of globin genes can be modulated by exogenous factors. The findings raise the possibility that the phenotype of HPFH is not simply the direct result of mutations in or around globin genes but the consequence of the mutations on the interaction of globin genes with trans-acting regulatory factors.

This paper reports a Sicilian family in which beta-thalassaemia, haemoglobin Lepore Boston-Washington and heterotocellular hereditary persistence of fetal haemoglobin (HPFH) were present in various combinations. The most interesting combination was that of Hb Lepore and heterocellular HPFH, which has not been previously reported. This subject was clinically normal, with the haematological picture of Hb Lepore trait and an unusually high level of HbF due to an increased number of circulating F cells.

The interaction between beta(0) thalassemia and an heterocellular form of hereditary persistence of fetal haemoglobin (HPFH), presumably of the Swiss type, has been studied in three generations of a family in which both traits occur. The haematological parameters and the segregation of the two characters in the family suggest that the propositus, a 52-year-old male from southern Sardinia, is homozygous for beta(0) thalassemia and carrier of the HPFH. In spite of the complete suppression of adult haemoglobin synthesis, the patient is not anaemic and shows only morphological abnormalities of the red cells associated with a moderate decrease of the erythrocyte life span. Studies of the synthesis of haemoglobin chains in vitro have revealed only a mild degree of unbalance in the propositus, with a gamma/alpha ratio of 0.67, and a very slight unbalance in a 3-year-old child heterozygous for beta thalassaemia and HPFH. Preliminary analysis of the linkage between this kind of heterocellular HPFH and the beta Hb locus has been performed, utilizing all the suitable families reported in the literature. Although positive lod scores (1.535) have been obtained at a recombination fraction of 0.20, the data available are not sufficient to conclude in favour or against the linkage between the beta Hb locus and the heterocellular type of HPFH.

The gamma-chain structure of a homozygote for HPFH Negro type, previously described by Acquaye and co-workers, and of 3 heterozygotes of the same family has been evaluated. G gamma and A gamma chains were present in a ratio of fetal type (7/3) in the homozygote and in ratios of 2/3 and 1/1 in the heterozygotes, in agreement with data of the literature. T gamma chains were absent in all the cases. Our results, compared with those previously reported for Negro and Greek HPFH, suggest that the T gamma gene is never linked with the HPFH determinant.