Prevalence of Haemoglobin Variants in Malaria Endemic Northeast India
The present study is an attempt to evaluate the relationship
of haemoglobinopathies, particularly Hb E and Plasmodium falciparum
malaria in northeastern region of India. The diverse autochthonous inhabitant
of this part of India exhibits variable gene frequency for βE-globin
gene. The geo-climatic condition of the region supports transmission of
Plasmodium falciparum malaria in northeastern parts of India. The
study revealed that HbE is predominant with a variable gene frequencies
in ethnic groups affiliated to Tibeto-Burman linguistic families. Prevalence
of Hb E is also associated with the linguistic affiliation of various
Tibeto-Burman linguistic families inhabiting in malaria endemic northeast
India. We have also observed a positive correlation (R2 = 0.703)
of βE-globin gene frequency and mean incidence of Plasmodium
falciparum infection (Pf %) in malaria endemic zones.
Haemoglobinopathies are the worldwide prevalent monogenic genetic disorders
with variable geographic distribution (Krafft and Breymann,
2004). In Southeast Asia and the Indian subcontinent, this has been considered
as common disorders of blood posing a major genetic and public health problem
(Fucharoen and Winichagoon, 1997). Amongst variant haemoglobins,
haemoglobin E (Hb E, β26 GAG→AAG) is the most common β-thalassaemic
haemobinopathy in Asian population affecting about 30 million inhabitants of
Southeast Asian (Lukens, 1999). High gene frequency for
Hb E is prevalent in autochthonous inhabitant, having linguistic and cultural
affiliation with the population of Southeast Asian countries, of the northeastern
part of Indian (Deka et al., 1987). Sickle cell
haemoglobin (Hb S, β6 GAG→GTG) in this part of India is
restricted to the Tea garden labour communities, a group of population brought
to Assam by the British colonial tea planters as indentured labourer from central,
eastern and southern India during mid 19th century (Balgir
and Sharma, 1988). Besides, Haemoglobin D (HbD, β121 GAA→CAA)
is reported in an Ahom family, affiliated Tai-Kadai linguistic group (Sharma
et al., 2003).
The unique geo-climatic conditions of the northeastern part of India facilitate
transmission of malaria in this part of the country (Mohapatra
and others, 1998). Malaria in this region is predominantly contributed by
Plasmodium falciparum (P. falciparum) with widespread distribution
of Chloroquine resistant strains (Mohapatra et al.,
1998; Satyanarayna et al., 1991). Hence, overlapping
of haemoglobinopathies and P. falciparum malaria persists in northeast
MATERIALS AND METHODS
In the present study, seven homogenously distributed ethnic groups concentrated
in different geographical locations of northeast India with variable Plasmodium
falciparum infection (Pf %) were included (Fig. 1).
Linguistic affiliations of the ethnic groups, excluding Tea garden labour
community, are represented in Fig. 2. The Tea garden
labour community is predominantly localized in Assam. Incidence of Plasmodium
falciparum malaria (pf%) of three consecutive years, of the respective
study districts, were acquired from the district health authorities of
the respective states of Northeast India (Table 1).
Six hundred fifty two blood samples were obtained randomly from the volunteers,
in EDTA vials, affiliated to seven ethnic groups of the region after obtaining
written consent from each individual (Table 1). The
seven ethnic groups represents in the study are Tangsa and Yobin (Lisu)
from the state of Arunachal Pradesh, Mishing, Deori and Tea garden Labour
community of Assam, Mizos from Mizoram and Tripuri from Tripura
State (Table 1).
||Distribution of the study population in Northeast India
|| Linguistic affiliation of the study population
|| Detail about the study population and malaria situation of
the study area
Haemolysate of individual samples were prepared and presence of haemoglobin
variants was identified initially by electrophoresis of haemolysate on cellulose
acetate using Tris-EDTA-Borate buffer pH 8.6 (Lewis et al.,
2001). Sickleing in whole blood, in presence of buffered Sodium dithionite,
was performed simultaneously for all samples to confirm the presence of Sickle
cell haemoglobin (Lewis et al., 2001). Further,
an aliquot of 5 μL of blood was transferred to 1 mL of Hemolysis Reagent,
a component of BioRad -thalassaemia Short Program kit and stored at 4°C.
The samples were transported to the Central laboratory maintaining the cold
chain and analysed in the VariantTM Hemoglobin Testing System (BioRad)
using β-thalassaemia Short Program within ten days of sample collection
adopting standard protocol.
RESULTS AND DISCUSSION
Hb E is the most prevalent variant haemoglobin in ethnic groups affiliated
to Tibeto-Burman linguistic family. Gene frequency for βE-globin
gene in these groups ranged from 0.006-0.569 with an overall prevalence
of 0.266. In addition to malaria status of the area, βE-globin
gene frequency is also associated with the population groups affiliated
to Tibeto-Burman linguistic family tree.
The Deori and Tripuri tribes affiliated to Bodo subgroup, expressed high
gene frequency (0.569 and 0.525) for βE-globin gene. Substantially
high gene frequency (0.403) was also observed in Mishing tribe, affiliated
to Tani subgroup. The Tangsas, affiliated to Konyak subgroup of Tibeto-Burman
linguistic family, indicates considerably low (0.084) gene frequency for
βE-globin gene. Significantly lower βE-globin
gene frequency was depicted in Yobin (0.006) and Mizo (0.008), affiliated
to Lolo-Burmese and Kuki-chin-Naga subgroups of Tibeto-Burman linguistic
family tree respectively. The gene frequency for sickle cell haemoglobin
in Tea garden labour community is 0.090.
Further, the study also indicated a positive correlation (R2
= 0.703) of βE-globin gene frequency and mean incidence
of Plasmodium falciparum infection (Pf%) (Fig. 3).
βE-globin gene frequency is considerably high in Deori
(0.569), Tripuri (0.525) and Mishing (0.403) tribes in areas with high
pf%. In contrast, substantially low gene frequency for βE-globin
gene is observed in Mizo (0.008) population inhabited in a highly malaria
endemic belt (Health and Family Welfare Department, Government of Mizoram,
Similarly, in a meso to hyper endemic malarial zone, Tangsa also demonstrated
low gene frequency (0.084) for βE-globin gene. However,
in a relatively malaria free area of Vijaynagar circle of Changlang district,
the Yobins exhibits lowest gene frequency (0.006) for βE-
||Prevalence of βE-globin gene in the different
ethnic groups of northeastern region and P. falciparum status of
the study area
Variable gene frequency for βE-globin gene in autochthonous
inhabitants of malaria endemic northeast India though partially support the
malaria hypothesis, still earlier postulation on association of number of other
evolutionary factors at microgeographic levels is also indicated in the present
study (Livingstone, 1983, 1985).
Occurrence of significantly low gene frequency (0.008) for βE-globin
gene in Mizo population of a highly malaria endemic district of northeast India
is probably associated with genetic diversity of the population. Linguistically,
Mizos are affiliated to Kuki-Chin-Naga sub group of Tibeto-Burman linguistic
family (Gordon, 2005). Likewise, in hyperendemic malarial
background lower mean Hb E frequency is prevalent in Thai populations, originating
from Upper Myanmar and southwestern Yunnan, is reported (Poolsuwan,
2003). The prevalence of lower gene frequency in Tangsa population of a
meso to hyper endemic malarial zone may have similar explanation. Neighbour-joining
tree constructed on DA distance matrix depicting the genetic relationship
between the twenty three populations of Arunachal Pradesh, based on two classical
genetic markers revealed, genetic difference of Tangsa people from other tribes
(Krithika et al., 2007). Occurrence of low gene
frequency for βE-globin gene in Yobins (Lisu) having ancestral
origin from Myanmar and Yunnan also indicates linguistic or affiliation of the
population in prevalence of βE-globin gene. Hence, in addition
to a positive correlation of the βE-globin gene with Pf% as
malaria endemicity (Fig. 3), genetic affiliation of the population,
it reflects that other genetic polymorphism including thalassemia and G-6PD
deficiency may also probably associated with the distribution of HbE in malaria
endemic zones of northeast India.
Researchers are thankful to Dr. K. Narain, Dr. H.K.D as and Dr. H.K.
Chaturvadi for their kind help and support during the fieldwork at Vijoynagar
circle of Arunachal Pradesh. Thanks are also due to Mr. R. Dutta and Mr.
S. Gogoi for technical assistance.
Balgir, R.S. and S.K. Sharma, 1988. Distribution of sickle cell haemoglobin in India. Indian J. Hemato Blood Transfus, 6: 1-14.
Deka, R., B. Gogoi, J. Hundrieser and G. Flatz, 1987. Haemoglobinopathies in Northeast India. Hemoglobin, 11: 531-538.
CrossRef | PubMed |
Fucharoen, S. and P. Winichagoon, 1997. Hemoglobinopathies in Southeast Asia: Molecular biology and clinical medicine. Hemoglobin, 21: 299-319.
Gordon, R.G. Jr., 2005. Ethnologue: Languages of the World 15th Edn., Tex.: SIL International, Dallas,.
Krafft, A. and C. Breymann, 2004. Haemoglobinopathy in pregnancy: Diagnosis and treatment. Curr. Med. Chem., 11: 2903-2909.
Direct Link |
Krithika, S., S. Maji and T.S. Vasulu, 2007. Geographic contiguity, patterns of gene flow and genetic affinity among the tribes of Arunachal Pradesh. India Int. J. Hum. Genet., 7: 267-276.
Direct Link |
Lewis, S.M., B.J. Bain and I. Bates, 2001. Dacie and Lewis Practical Haematology. 9th Edn., Churchill Livingstone, London, ISBN-13: 9780443063770, Pages: 633.
Livingstone, F.B., 1983. The Malaria Hypothesis. In: Distribution and Evolution of Hemoglobin and Globin Loci, Bowman, J.E. (Ed.). Elsevier, New York, ISBN: 0444007938, pp: 15-44.
Livingstone, F.B., 1985. Frequencies of Hemoglobin Variants: Thalassemia, The Glucose-6-Phosphate Dehydrogenase Deficiency, G6PD Variants and Ovalocytosis in Human Populations. 1st Edn., Oxford University Press, Oxford, UK., ISBN: 0195036344.
Lukens, J.N., 1999. The Abnormal Hemoglobin's: General Principles. In: Wintrobe’s Clinical Haematology, Richard Lee, G., J. Foerster, J. Lukens, F. Paraskevas, J.P. Greer and G.M. Rodgers, (Eds.). Williams and Wilkins, USA, ISBN: 0683182420 pp: 1329-1345.
Mohapatra, P.K., A. Prakash, D.R. Bhattacharyya and J. Mahanta, 1998. Malaria situation in North-Eastern region of India. Icmr Bull., 28: 21-30.
Poolsuwan, S., 2003. Testing the malaria hypothesis for the case of Thailand: A genetic appraisal. Hum. Biol., 75: 585-605.
Satyanarayna, S., S.K. Sharma, P.K. Chelleng, P. Dutta, L.P. Dutta and R.N.S. Yadav, 1991. Chloroquine resistant P. falciparum malaria in Arunachal Pradesh. Indian J. Malariol., 28: 137-140.
Sharma, S.K., S. Gogoi, R. Dutta and J. Mahanta, 2003. Haemoglobin D in a Mongoloid non-tribal family: First report from northeast India. Curr. Sci., 84: 252-253.
ASCI | PubMed |