Phenotypic and quantitative relationship of red cell

Transcription

1 Jurnal f Medical Genetics, 1981, 18, Phentypic and quantitative relatinship f red cell acid phsphatase with haemglbin, haptglbin, and G6PD phentypes N SAHA AND N PATGNARAJAH Frm the Faculty fmedicine, niversity fkhartum, Khartum, Sudan SMMARY The phentypic and quantitative relatinship f red cell acid phsphatase with haemglbin, haptglbin, and G6PD phentypes was investigated in three ppulatins in the Sudan and ne ppulatin in Nilgiris, ndia. N significant cnsistent assciatin f red cell acid phsphatase phentypes was bserved with these plymrphisms. Hwever, there was a lack f acid phsphatase AB in G6PD deficient subjects frm Nilgiris. The relative quantitative expressin f red cell acid phsphatase genes pa, pb, and pc was 1, 1 2, and 1 3, respectively, The red cell acid phsphatase - activity was higher (15%) in the presence f raised haemglbin A2 and in sickle cell anaemia (21 %). Thse with Hp2 had 18% higher level f acid phsphatase than thse with Hp'. G6PD deficient subjects had a lwer level f acid phsphatase activity (2%) than thse with nrmal G6PD activity. t has been pstulated that the prevalence f certain genes, like the sickle cell, thalassaemia, and glucse- 6-phsphate dehydrgenase (G6PD) genes, is f selective imprtance in human ppulatins.1 2 This suggests that the deleterius r lethal effects f these genes in a hmzygus state are balanced by sme advantage ffered by the heterzygus state. There may be sme reginal variatins in the type and extent f these selective factrs in different ppulatins.3 Red cell acid phsphatase, which is cntrlled by three cmmn c-dminant alleles pa, p,b and pc at an autsmal lcus, has been reprted t be plymrphic in man.4 The enzyme activity f the gene dsage f these three alleles is in the increasing rder pa, <pb, <pc.5 6 Recently, an interesting assciatin f red cell acid phsphatase, G6PD deficiency with favism, and past incidence f malaria has been reprted in Sardinians and Rmans.7-9 The data suggested that the susceptibility f the subjects t haemlytic manifestatins was highest in thse carrying the acid phsphatase genes pc and pa. Hwever, Mdian et al' reprted a lack f assciatin f red cell acid phsphatase phentypes with past malarial mrbidity in the same ppulatins. The precise functinal significance f red cell acid phsphatase is nt knwn. G6PD deficient Caucasian subjects f the Mediterranean type have been Received fr publicatin 11 September 198 reprted t have decreased red cell acid phsphatase activity."1-13 Hwever, later studies in Sardinians did nt cnfirm this thalassaemia can be respnsible fr an increased red cell activity.6 Negr G6PD deficient subjects had nrmal levels f acid phsphatase.11 Material and methds n the curse f ppulatin genetic studies in the Sudan and Nilgiris, ndia, data were cllected n the phentypic distributin f red cell acid phsphatase, haemglbin, haptglbin, and G6PD phentypes. The material cmprised 237 samples frm the Nuba muntains, 33 samples frm the Gabel Merah muntains, 41 samples frm Khartum, and 234 samples frm Nilgiris, ndia. A subsample f 296 male subjects frm the Sudan was quantified fr bth red cell acid phsphatase and G6PD activities. The methds f qualitative typing by starch-gel electrphresis fr acid phsphatase, haemglbin, haptglbin, and G6PD have been described earlier.15 The prcedure fr red cell G6PD assay has been described elsewhere.'6 Red cell acid phsphatase activity was determined by a standard prcedure using p-nitrphenyl phsphate as the substrate and expressed in,uml p-nitrphenl liberated in half an hur per g haemglbin at 37C. 271 J Med Genet: first published as /jmg n 1 August Dwnladed frm n 2 September 218 by guest. Prtected by

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3 Phentypic and quantitative relatinship f red cell acid phsphatase Results and discussin ACD PHOSPHATASE TYPES N RELATON TO HAEMOGLOBN TYPES The phentypic distributin f red cell acid phsphatase in subjects with different types f haemglbin (AA, AS, SS) in three grups frm the Sudan and ne grup frm Nilgiris, ndia, is presented in table 1. There was n significant difference in the distributin f red cell acid phsphatase types accrding t the type f haemglbin in a ttal sample f 122. T ur knwledge there has been n study reprted which has examined the assciatin f acid phsphatase types with different haemglbin types. The assciatin f the sickle cell gene with malaria is well-dcumented,' whereas that f red cell acid phsphatase plymrphism is disputed9 1 Therefre the lack f assciatin f red cell acid phsphatase plymrphism with the sickle cell gene in the present investigatin is cmpatible with the abve. ACD PHOSPHATASE PHENOTYPES N RELATON TO HAPTOGLOBN TYPES The distributin f red cell acid phsphatase phentypes in subjects with different haptglbin types in ppulatins frm three lcalities in the Sudan and frm Nilgiris in ndia is presented in table 2. The gene frequencies f haptglbins vary in different ppulatins and the Hp 'O' phentype has been reprted with a high frequency in African ppulatins. Hp 'O' phentype has been claimed t have an acquired rigin and is related t the haemlytic diseases. n general, the frequency f Hp' is higher in ppulatins where the incidence f malaria was high in the past. The present study shws that the distributin f red cell acid phsphatase types is similar in relatin t the haptglbin phentypes in all the fur ppulatin grups. TABLE 3 ACD PHOSPHATASE TYPES N RELATON TO G6PD TYPES The distributin f red cell acid phsphatase types in relatin t G6PD types in male subjects frm the Sudan and Nilgiris is presented in table 3. Females have been excluded because f the difficulty in determining the G6PD phentypes. Owing t the small number f uncmmn variants in the three ppulatin grups f the Sudan, they have been cmbined. N significant difference in the distributin f red cell acid phsphatase types was bserved in subjects with different G6PD types in the Sudanese sample, whereas there was a lack f AB phentypes f acid phsphatase (x2=3 *9) and lack f pb in GdB in the Nilgiris ppulatin. Such an assciatin in ne ppulatin may be a chance ccurrence. This bservatin is in agreement with the reprted assciatin f pa and favism.7 8 The frequency f pc was very lw in the present ppulatins, s a large sample needs t be investigated t find any assciatin. Furthermre, the mst cmmn G6PD deficiency is GdA- rather than GdB in African ppulatins and favism is uncmmn in GdAsubjects. Bttini et a17 8 bserved this assciatin f red cell acid phsphatase and G6PD nly in the deficient subjects with favism. Mrever, the ppulatin f the Sudan has a high degree f inbreeding which may cmplicate the expressin f these genes, as reprted in the Sardinian ppulatin.'7 RED CELL ACD PHOSPHATASE ACTVTY N DFFERENT ACD PHOSPHATASE, HAEMOGLOBN, HAPTOGLOBN, AND G6PD PHENOTYPES The activity f red cell acid phsphatase in different phentypes in 296 subjects frm the Sudan is presented in table 4 and the figure. The levels f acid phsphatase activity in /g haemglbin in Distributin f red cell acid phsphatase phentypes in relatin t G6PD types (males nly) Acid G6PD phentypes phsphatase phentypes Sudan All Nilgiris A+ B+ A+&B+ A- B- Gd- Gdlnt deficients B+ B- A (2-3) (5.5) (5-2) (6-6) (2-8) (14-8) AB (14-) (13-6) (13-6) (17-9) (29-9) (11 1) B (81.4) (73-9) (74.5) (72-6) (67.3) (74-1) CB, CA, C (2-3) (6-6) (6-2) (2-8) Ttal * *includes ne each f DB and RB Figures in parentheses dente percentages 273 J Med Genet: first published as /jmg n 1 August Dwnladed frm n 2 September 218 by guest. Prtected by

4 274 TABLE 4 Enzyme activity* f red cell acid phsphatase phentypes Phentypes n Enzyme activity A ±54-14 AB *83±75*67 B ±75-67 CB ±96-55 C 1 7 RB 1 23 DB 1 1 Ttal ±93-6 *lml p-nitrphenl released in - 5 h per g haemglbin different phentypes are cmparable with thse in English and talian ppulatins.56 The frequency distributin f the enzyme activity in the mst cmmn phentype (B) is slightly psitively skewed (figure). The red cell acid phsphatase activity in different haemglbin, haptglbin, and G6PD phentypes is presented in table 5. The enzyme activity is raised in the presence f a raised level f haemglbin A2 and in sickle cell anaemia, but the difference is nt significant in either case because f the small size f the sample. The presence f sickle cell trait did nt alter the level f acid phsphatase. The results suggest that the change in activity f acid phsphatase is nt because f the presence f thalassaemia. The red cell acid phsphatase activity in subjects with different haptglbin phentypes shwed an insignificant higher level f enzyme activity in Hp2. Hp had a lwer level f acid phsphatase activity, which suggests a prbable rle f acid phsphatase in the maintenance f the structural integrity f the red cell membrane, thereby preventing haemlysis. G6PD deficient male Sudanese had a lwer level f red cell acid phsphatase activity cmpared with nrmal subjects, but the difference is nt statistically a a. 2 N Saha and N Patgunarajah TABLE 5 Red cell acid phsphatase activity* in relatin t haemglbin, haptglbin, and G6PD types Phentypes n Acid phsphatase Hb AA ±76-43 Hb AA ±66-45 Hb AS ±65.3 Hb SS 7 158*43 ±54-65 Hb AF HbAO Hp ±63-72 Hp ±61-38 Hp ±57-97 Hp ±69-63 GdA ±69-58 GdB ±76-68 GdB int *48±79*4 GdB Khartum 3 139*33±95*27 Gd ±6.2 Crrelatin f AP and G6PD activities: r = *pml p- nitrphenl released in - 5 h per g haemglbin significant. This is in agreement with earlier reprts f decreased activity in G6PD deficient Caucasians and Greeks."1-14 Hwever, it is cntrary t the reprted raised levels f acid phsphatase in 3-thalassaemia and G6PD deficient Rmans and Sardinians.814 n the talian ppulatin, a raised level f the enzyme activity was present in G6PD deficient subjects when it was assciated with 3-thalassaemia. This suggests that the effect is the result f the presence f thalassaemia rather than the G6PD deficiency in the talians. The level f the acid phsphatase was higher in the presence f a raised level f Hb A2 in this ppulatin als. This apparent discrepancy may be because G6PD deficiency in African ppulatins and in the Sudan is mstly f the Negr type (GdA-), whereas the deficiency in the Mediterranean is the result f GdB, r the differential expressin in different ppulatins. Furthermre, the phentypic assciatin f acid phsphatase was bserved nly in cases f G6PD deficiency with favism in the talian sample. There was a pr psitive crrelatin f red cell acid phsphatase and G6PD activities (r=o 13). This differential selective adaptability f different genes in different ppulatins f the wrld in respnse t different envirnmental cnditins such as temperature, humidity, radiatin, infective diseases, etc, may be respnsible fr the cnflicting results f the assciatin f G6PD deficiency and ther abnrmal haemglbins with past malarial mrtality and mrbidity '4 References Enzyme activity 'Allisn AC. Plymrphism and natural selectin in human ppulatins. Quant Bil 1964; FGRE Frequency distributin 29: f the enzyme activity 2 Haldene JBS. Natural selectin in man. Acta Genet 1956; in B phentype f acid phsphatase. 6: J Med Genet: first published as /jmg n 1 August Dwnladed frm n 2 September 218 by guest. Prtected by

5 Phentypic and quantitative relatinship f red cell acid phsphatase 3 Saha N, Benerjee B. Erythrcyte G6PD deficiency in Chinese and Malays f Singapre. Trp Gegr Med 1971; 23: Hpkinsn DA, Spencer N, Harris H. Red cell acid phsphatase variants: a new human plymrphism. Nature 1963;199: Spencer N, Hpkinsn DA, Harris H. Quantitative differences and genes dsage in the human red cell acid phsphatase plymrphism. Nature 1964 ;21 : Mdian G, Filippi G, Brunelli F, et al. Red cell acid phsphatase activity in carriers f,3-thalassaemia and glucse-6-phsphatase dehydrgenase deficiency. sr J Med Sci 1968;4: Bttini E, Lucarelli P, Agstin R, et al. Favism: assciatin with erythrcyte acid phsphatase phentypes. Science 1971; 171: Bttini E, Lucarelli P, Bastiann V, Glria F. Erythrcyte acid phsphatase plymrphism and haemlysis. J Med Genet 1972;9: Palmarin R, Agstin R, Glria F, et al. Red cell acid phsphatase: anther plymrphism crrelated with malaria? Am JPhys Anthrpl 1975; 43: Mdian G, Filippi G, Brunelli F, et al. Studies n red cell acid phsphatase in Sardinia and Rme. Absence f crrelatin with past malarial mrbidity. Acta Genet 1967; 17: Oski FA, Shahidi NT, Diamnd LK. Erthyrcyte acid 275 phsphmnesterase in glucse-6-phsphate dehydrgenase deficiency in Caucasians. Science 1963 ;139: Chremis C, Kattamis C, Zanns-Marilea L. Erythrcyte acid phsphmnesterase in G6PD-deficient Greeks. Lancet 1964;i: Kattamis C, Zanns-Marilea L. Acid phsphatase activity in G6PD-deficient Greeks. Prc 1th Cngr nt Sc Bld Transf, Stckhlm, 1965: Schettini F, Melni T, Mela C, Fanciulli G. Red cell acid phsphatase in nrmal and G6PD-deficient Sardinian subjects. Acta Haematl 1965; 33: `5 Saha N, Samuel APW, Omer A, et al. A study f sme genetic characteristics f the ppulatin f the Sudan. Ann Hum Bil 1978; 5: Samuel APW, Saha N, Omer A, Hffbrand AV. Quantitative expressin f G6PD activity in different G6PD and haemglbin types in a Sudanese ppulatin. Hum Hered (in press). 17 Wrkman PL, Lucarelli P, Agstin R, et al. Genetic differentiatin amng Sardinian villages. Am J Phys Anthrpl 1975; 43: Requests fr reprints t Prfessr N Saha, Department f Medical Genetics, niversity f mea, S me'a, Sweden. J Med Genet: first published as /jmg n 1 August Dwnladed frm n 2 September 218 by guest. Prtected by