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Distribution of abnormal hemoglobins and glucose-6-phosphate dehydrogenase variants in 1200 school children of Bahia Brazil.

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AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 53509-512 (1980)
Distribution of Abnormal Hemoglobins and Glucose-6Phosphate Dehydrogenase Variants in 1200
School Children of Bahia, Brazil
ELAINE s.AZEVEDO, AURISTELA F.P. ALVES, MARIA CHRISTINA B.
OLYMPIO DA SILVA, MAlUA DAS GRACAS F. SOUZA,-ANGELA MARIA
V. MUNIZ DIAS LIMA, AND WIGBERTO CUNHA AZEVEDO
Laborakjrio de Genhtica Mhdica, Hospital Prof. Edgard Santos, Universidade
Federal da Bahia, 40.000 Salvador, Bahia, Brasil
KEY WORDS
Bahia, Brazil
Race admixture, Hemoglobin, GGPD,
ABSTRACT
School children from Bahia, Brazil were studied for hemoglobin
and glucose-6-phosphate dehydrogenase electrophoretic variants. Eighty-nine
heterozygotes Hb AS and 41 Hb AC were identified out of 1200 children. In a
subsample of 369 male children there were 38 Gd A-, 38 Gd A, and six Gd Med. An
example of Gd MG was identified and evidence is added to the suggestion that this
allele is not rare in Brazil.
Hemoglobin (Hb) and glucose-6-phosphate
dehydrogenase (G6PD)genetic systems are two
commonly studied human polymorphisms in
many parts of the world. In Bahia, however, the
frequency of G6PD alleles has never been investigated a t a population level (AzevGdo and
Azevgdo, 1974; Azevgdo et al., 1978), and the
hemoglobin variants have been studied mainly
on hospital samples (Kalmus, 1957; Machado,
1958;Peixoto et al., 1963;Ramos and Pedreira,
1970; Ramos et al., 1975).
In the present study we report the results of a
survey for abnormal Hb in 1200school children
and the findings for G6PD gene frequencies in a
subsample of 369 male children.
ORIGIN OF SAMPLE
School children from first degree public
school in Salvador, capital of the State of Bahia,
were asked to cooperate for the study. Because
all those attending public schools in Brazil pay
no fee, the children there are mainly from low
socioeconomicclasses, which represent not only
the largest classes in the city but also those
having more Black admixture.
RACIAL ADMIXTURE
To assess the proportion of Black admixture
the children were subjectively classified racially as described by Krieger et al. (1965).Skin
color, hair type, and facial features were the
variables considered for assigning a child to one
0002-9483/8015304-0509$01.10C 1980 ALAN R. LISS. INC.
of the following groups: White, light mulatto,
medium mulatto, dark mulatto, Black, light
Indian, and dark Indian.
LABORATORY PROCEDURES
Venous blood samples were drawn in the
school itself and refrigerated during transportation to the laboratory located in the same
city. Starch gel electrophoresis (Smithies,
1955) prepared with Brazilian starch (Carvalho and Azevgdo, 1976)was used for both Hb
and G6PD studies. A discontinuous buffer system pH 8.6 (Poulik, 1957) was used for Hb,
while G6PD was run in phosphate buffer pH 7.0
(Fildesand Parr, 1963).All electrophoresis was
carried out a t 4°C. The G6PD zone of activity
was developed by incubating the sliced gel with
an agar overlay containing the specific reaction
mixture (Boyer et al., 1962).
RESULTS
Out of 1200 school children 89 were
heterozygotes Hb AS and 41 heterozygotes Hb
AC giving the following gene frequencies:
0.946 forHb A, 0.037 forHb S, and 0.017 forHb
C. The overall genotype frequencies and test for
Hardy-Weinberg equilibrium are given in
Table 1.
The racial groups’ distribution and the frequency of heterozygotes Hb AS and Hb AC
Received December 3, 1979; accepted May 16, 1980
510
E.S. ME-DO
within each group are given in Table 2.
Out of 369 male children 45 (0.122) had
G6PD deficiency. The overall distribution of
G6PD genotypes by racial groups is shown in
Table 3.
ET AL.
Racial intercrosses between Blacks and
Whites in Bahia is well known in the past and
present. As a result, data from the national
census of 19501 showed that 29.6%of Bahia’s
population was White, 51.wo mulatto, and
19.Z0 Black (Salzano and Freire-Maia, 1970).
However, as shown in the present paper, the
so-called White group is the least Black. The
frequencies of H b S, H b C, Gd A, and Gd Aalleles increase from White to Black, keeping
well-balanced frequencies in the light, medium, and dark mulattoes (Tables 2 and 3). All
the presently available data on abnormal hemoglobin in Bahia are summarized in Table 4.
DISCUSSION
Black Africans constituted the major racial
group in the formation of Bahia’s population.
Allowing for many historical uncertainties a
total of 1,200,000 slaves is estimated to have
been imported to Bahia from 1678 to 1851
(Verger, 1976). However, other historians believe the slave traffic to Brazil began as early as
1530 (Boxer, 1969).
lUnfortunately, the 1960 and 1970 census did not classify for race.
TABLE 1 . Hemoglobin genotypes and gene frequencies in 1200 school children of
B a h q Brazil and expected numbers under Hardy-Weinberg equilibrium
Observed
Freq
~-
n
Genotypes
HbAA
Hb AS
Hb AC
Hbsc
Hbss
Hb
cc
Total
Expected
-~
-
~
Freq
n
1070
89
41
0
0
0
0.8916
0.0742
0.0342
0.0000
0 . m
0 . m
1073.88
84.00
38.64
1.44
1.68
0.36
1200
1.0000
1200
(p’)
(2pq)
(2pr)
(2qr)
(q2)
(4’)
Gene frequencies
0.8949
0.0700
0.0032
p = 0.946 (Hb A)
q = 0.037 (Hb S )
r = 0.017 (Hb C )
0.0012
0.0014
0.0003
1 .oooo
1.000
TABLE 2 Racial group distribution and frequency of abnormal hemoglobin within groups
in 1200 school children of Bahia, Brazil
School
children
Racial
groups
~~
HbAA
- .~
Freq
Freq
n
2
0.113
0.154
0.314
0.239
0.178
0.002
127
169
341
258
173
2
1200
1.000
1070
n
n
Hb AS
Freq
~
n
Hb AC
Freq
~-
White
Light mulatto
Medium mulatto
Dark mulatto
Black
Dark Indian
Totals
136
185
376
287
214
0.934
0.914
0.907
0.899
0.808
1.000
6
12
20
21
30
0
0.044
0.064
0.055
0.073
0.140
0.000
3
89
4
15
8
11
0.022
0.022
0.040
0.028
0.052
0
0.000
41
TABLE 3. Glucose-6-phosphate dehydrogenase (G6PD) gene frequencies by racial groups
in 369 male school children o f Bahia. Brozil
Male school
children
n
Freq.
White
Light mulatto
Medium mulatto
Dark mulatto
Black
Dark Indian
32
61
128
Totals
369
0.087
0.165
0.347
90 0.244
57 0.154
1 0.003
1.000
n
GdB
Freq.
28 0.875
52 0.852
98 0.766
66 0.733
40 0.702
1 1.OOO
285
n
Gd Med
Freq.
Gene frequencies
GdA
Gd An
Freq.
n
Freq.
1
0.031
-
-
5
0.039
5
14
-
11
7
-
-
6
‘One fully deficient and other migrating hke Gd MG (AzevOdo and Yoshida, 1969).
1
-
38
0.031
0.082
0.109
0.122
0.127
-
2
4
11
13
8
-
38
0.063
0.066
0.086
0.145
0.140
-
n
-
2’
2
Gd?
Freq.
-
0.035
-
HB S AND G6PD IN BAHIA, BRAZIL
511
The frequency of H b AS phenotype varies
around 6% in all studies but one. It is possible
that the unique finding of 16% sicklers in a
sample of 70 is biased due to the sample size.
The finding of Gd Med in the present study is
explained by European migration other than
Portuguese. For example, 1,500,000 Italians
migrated to Brazil in the period 1884-1944
(Salzano and Freire-Maia, 1970). Because
these migrations are rather recent the Gd Med
allele is more frequent in the less Black, a s
shown in Table 3.
G6PD deficiency was found in combination
with hemoglobin S in five cases. Considering
the isolated genotype frequencies the expected
number of double carriers was three, giving a n
observediexpected ratio of 1.7. This finding is in
agreement with those reported by Salzano et al.
(1968)of no evidence for interation between the
Hb and the G6PD polymorphisms.
Finally, the finding of a Gd MG-like G6PD
variant adds more evidence that this allele is
not rare in Brazil. In the first reported Gd MG,
the proposita was a female homozygote Gd
MGIGd MG, which led to some discussion as to
whether this genotype was formed due to inbreeding or to a polymorphism (Azevgdo and
Yoshida, 1969). Subsequently, another carrier
of Gd MG was identified in South Brazil (Hutz
et al., 19771, and very recently we found another example of G d MG i n t h e island of
Itaparica off the coast of Bahia.
I
I
I
I
0
m
2
ACKNOWLEDGMENTS
We are very thankful to CNPq i n Brazil and
to OEA for financial support, and to Vanilson
Silva and M.A. Machado for technical help.
d
m
8
LITERATURE CITED
m
0
2
8
N
f
bC
...
-
4
E
2
B
b
s
*g
1
F
Azevzdo, ES, and Azevedo, TFS (1974) Glucose-6-phosphate
dehydrogenase deficiency and neonatal jaundice in Bahia,
Brazil. Ci. Cult., 26:1044-1047.
Azevao, WC, Silva, MCF, Grassi, MCB, and Azevedo, ES
(1978) Deficiencia de glucose-6-fosfato desidrogenase em
pacientes de um hospital geral de Salvador, Bahia. Rev.
Bras. Pesq. Med. Biol., 11:49-52.
Azevzdo, ES, and Yoshida, A (1969) Brazilian variant of
glucose-6-phosphate dehydrogenase (Gd Minas Gerais).
Nature, 222t380-382.
Boxer, CR (1969) The Portuguese Seaborne Empire 14151825. Hazel1 Watson and Viney Ltd, Great Britain.
Boyer, SH, Porter, IH, and Weilbacher, RG (1962) Electrophoretic heterogeneity of glucose-6-phosphate dehydrogenase and its relationship to enzyme deficiency. Proc. Nat.
Acad. Sci., 48(10):1868-1876.
Carvalho, RES, and Azevgdo, ES (1976) Melhoria na separac5o eletroforetica de proteinas atraves de substituigio do
amido importado por amido brasileiro commercial. Ci.
Cult., 28t1507-1508.
Fildes, RA,andParr, CW (1963)Humanred cell phosphogluconate dehydrogenase. Nature, 2Wt890-891.
Hutz, M, Yoshida, HA, and Salzano, FM (1977) Three rare
512
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GGPD variants from Port0 Alegre, Brazil. Hum. Genet.,
39t191-197.
Kalmus, H (1957)Defective colour Vision, P.T.C. tasting and
drepanocytosis in samples from fifteen Brazilian populations. Ann. Hum. Genet., 21:313-317.
Krieger, H, Morton, NE, Mi, MP, Asevao, ES, Freire-Maia,
A, and Yasuda, N (1965) Racial admixture in north-eastern Brazil. Ann. Hum. Genet., 29.113-125.
Machado, L. (1958) Da inci&ncia de drepanocitemia em
grups de individuos da cidade do Salvador. Med. Cir.
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Peixoto, LIS, Pedreira, CM, and Lopes, KM (1963) Estudo
genetic0 de uma comunidade nordestina (Paulo Afonso,
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Poulik, MD (1957) Starch gel electrophoresis in a discontinuous system of buffers. Nature, 180.1477.
Ramos, KML, and Pedreira, CM (1470) Estimativas da frequgncia da hemoglobina C em grupos populacionais da
Bahia. XXII ReuniSo da SOC.Bras. Prog. Ci., Salvador,
Bahia, Brazil.
Ramos, ML, Nascimento, ML, Pereira, MP, and Valois, CV
(1975) Incidhcia de variantes de hemoglobina na cidade
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