Edgar J Ahern

Haemoglobin F Jamaica (α2γ261 Lys→Glu; 136 Ala)

Summary. Two siblings of mixed Negro, East Indian and Caucasian parentage showed an abnormal haemoglobin component in infancy which had electrophoretic characteristics similar to Hb F Roma (Silvestroni & Bianco, 1963). The amino‐acid substitution responsible for the peculiar electrophoretic mobility was found to be in the gamma polypeptide chain (γ— 61(E5) Lys→Glu). The finding of an alanyl residue at position 136 of the γ‐chain of the abnormal component in the first born of these infants was repeated in the abnormal γ‐chain of the second infant. No functional abnormalities were found to be associated with this abnormal haemoglobin, which is designated Hb F Jamaica.

Haemoglobin Spanish Town alpha27 Glu replaced by Val (B8)

Abstract A new alpha chain variant Hb Spanish Town, α27 Glutamic acid - Valine, was detected in the cord blood of a Jamaican Negro infant. In the mother the adult component (α2Spanish Townβ2) has an electrophoretic mobility between haemoglobins S and F at alkaline pH and measures 11.0–12.0% of the total haemoglobin.

Further characterisation of haemoglobin F Texas I: γ5 glutamic acid → lysine; γ136 alanine

Abstract The human foetal haemoglobin consists of α and γ chains of which the latter may either have a residue of alanine or of glycine at position 136. The γ chain of the human foetal haemoglobin variant haemoglobin F Texas I, which has a substitution Glu → Lys in position 5 was found to have an alanine at position 136.

Globin synthesis in the Jamaican Negro with beta-thalassaemia.

Summary. Globin synthesis was studied in three Jamaican Negro families with 18 heterozygotes and five homozygotes for β‐thalassaemia. Synthesis of the β‐chain of Hb A in the peripheral blood of heterozygotes was equal to that of α‐chain in 10 patients and was decreased in the remainder. In one patient with Hb C β‐thalassaemia, the β/α ratio was normal. These findings were similar to those in American Negroes, but differed from those in Caucasians with β‐thalassaemia trait, in each of whom the β/α ratio was decreased. Globin synthesis was balanced in the bone marrows of Negro and Caucasian heterozygotes. Despite the milder clinical disease in Negro homozygotes as compared to Caucasian patients, the β/α synthesis ratios were similar in both groups.

Haemoglobin F Victoria Jubilee (α2 Aγ2 80 Asp → Tyr)

Abstract A new A γ chain haemoglobin variant, haemoglobin F Victoria Jubilee, with an electrophoretic mobility slightly anodal to haemoglobin F Port Royal, was found in a Jamaican infant. The amino acid residue substitution of 80 Aspartic Acid → Tyrosine was associated with alanine in position 136. Haemoglobin F Victoria Jubilee constituted about 7.0% of the total haemoglobin F.

Further characterization of haemoglobin F hull γ121 glutamic acid → lysine; γ136 alanine

Abstract Variants of human foetal haemoglobin ( α 2 γ 2 ) may have either an alanine ( A γ chain) or a glycine ( G γ chain) residue at Position 136 of the γ chain. The substitution characteristic of haemoglobin F Hull ( γ121 Glu → Lys ) was found in a A γ chain.

The Prevalence of the Rarer Inherited Haemoglobin Defects in Adult Jamaicans

Summary. The prevalence of several haemoglobin defects, including the traits for β‐thalassaemia (0.8%), hereditary persistence of foetal haemoglobin (0.2%) and the abnormal delta chain haemoglobin, Hb B2 (2.4%), were determined from the combined results of surveys conducted on adults in a suburban and a rural community. Mean Hb A2 levels of 2.6 ± 0.4%, 5.3 ± 0.5% and 2.0 ± 0.2% were found in 639 Hb A homozygotes, seven β‐thalassaemia traits and three traits for hereditary persistence of foetal haemoglobin (HPFH), respectively. Levels of alkali resistant haemoglobin (A.R. Hb) ranged from 0.6 to 7.3% in the β‐thalassaemia traits and were 21.0, 19.0 and 16.0% in the three HPFH traits; the remaining 770 subjects in whom A.R. Hb was measured had a mean value of 0.6 ± 0.6%.

Gamma Chain Variants in Jamaican Newborns

15,661 cord bloods from Jamaican infants were examined for abnormal hemoglobins using alkaline cellulose acetate electrophoresis for the initial screening, supplemented by acid agar gel electrophoresis for samples exhibiting abnormal hemoglobin bands. Of the 16 electrophoretic variants which were detected, six were fully characterized and found to be: four Hb F Port Royal (alpha2 Ggamma2 125 Glu replaced by Ala) and two Hb F Victoria Jubilee (alpha2Agamma2 80 Asp replaced by Tyr). The Hb F Port Royal samples each constituted about one eighth of the total Hb F as did seven additional samples presumed to be Hb F Port Royal. The infants with this variant exhibited no special hematological characteristics or other consistent associations. Both Hb F Victoria Jubilee samples occurred in somewhat lower proportions of the total Hb F compared with Hb F Port Royal and exhibited an apparent increase of free alpha chains in the whole hemolysate. The data available on detectable gamma chain variants suggest that a specific point mutation may occur in either a HbGgamma or a HbAgamma locus.

A second example of haemoglobin F Texas I (α2Aγ25Glu→Lys) in a Jamaican infant

Abstract A second example of Hb F Texas I, Aγ5Glu→Lys, which constituted approximately 1 8 of the total Hb F, was found in a Jamaican infant.