Annals of Human Biology, March–April 2005; 32(2): 113–116

EDITORIAL

Genetics and Population Health

A. H. BITTLES1 & W. N. ERBER2

1Centre for Human Genetics, Edith Cowan University, Perth, Australia, and 2Department of

Haematology, Addenbrookes Hospital, Cambridge, UK

There has been a widespread belief that genetic disorders are of little importance in

low income countries, an opinion that is perhaps understandable given the often daunting

prevalence of infectious diseases and nutritional problems faced by these populations.

The failure to recognize genetic disorders as significant contributors to the overall disease

profile of low income countries is, however, a serious error. For example, an estimated

7.6 million children are born per year with a severe congenital or genetic disorder (Alwan

and Modell 2003), and one in seven of the world’s population are carriers of a haemoglobin

disorder (WHO 2002). In both cases a large majority of those affected are resident in

low income countries, which currently comprise over 80% of the global population

(PRB 2004). There is also convincing preliminary evidence that some sub-populations are

genetically predisposed to contract serious infectious diseases, including tuberculosis and

leprosy (Pitchappan 2002). Further, because of the requirement to treat �-thalassaemia

major individuals with regular blood transfusions, in 2003 Thalassaemia International

Federation estimated that 30–80% of all cases worldwide were infected with hepatitis B

and/or hepatitis C, a testament to the lack of adequate blood screening facilities

in low income countries. Thus the contribution of genetic disorders to global population

disease profiles, directly and indirectly, is of major significance.

The aim of the conference Genetics and Population Health, from which the present

collection of papers was selected, was to review the current global prevalence

and distribution patterns of genetic disease. The 17 invited papers are presented in five

sections:

(1) Haemoglobin disorders as a paradigm of genetic disease;

(2) Population genetic structure as affected by migration, marriage preference and

subdivision;

(3) Medical and community genetics in countries with different resource bases and

religious influences;

Correspondence: Professor A. H. Bittles, Centre for Human Genetics, Edith Cowan University, 100 Joondalup Drive, Perth,

Western Australia 6027, Australia. E-mail: a.bittles@ecu.edu.au

ISSN 0301–4460 print/ISSN 1464–5033 online/05/020113–116 # 2005 Taylor & Francis Group Ltd

DOI: 10.1080/03014460500089432

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(4) Health care delivery for genetic disorders in multi-ethnic, multi-cultural developed

societies; and,

(5) Bioinformatics in the diagnosis and care of patients with genetic disorders.

Genetic disorders of haemoglobin were used as a model to examine the adverse impact

of inherited disorders at individual, family, community and population levels, and to

consider how this impact might be ameliorated. These approaches are illustrated in the lead

paper by Weatherall on the attitudes of the World Health Organization and national health

agencies to genetic disease, and by Chui who discusses changing clinical and public

health attitudes to �-thalassaemia, a disorder which increasingly is accepted as a major

health problem. The studies by Firdous and Garewal et al. describe the establishment

of population-based screening and prenatal diagnosis programmes for �-thalassaemia in

The Maldives, an island nation recently devastated by the Indian Ocean tsunami, and

North India, respectively.

The three papers by Hussain, McElreavey and Quintana-Murci, and Patton deal

primarily with the roles of subdivision, migration and marriage preferences on popula-

tion genetic structure. In Western societies Islam is often portrayed as a monolithic

religion. Hussain describes the multiple population subdivisions that exist in Pakistan,

variously based on religious principles and beliefs, ethnicity and geographical location.

Using Y-chromosome and mtDNA analyses, McElreavey and Quintana-Murci

demonstrate how the historical movements of populations, some community- and

sex-specific, can influence the present-day genetic structure of populations. Their

data also cast light on the genetic origins of different South Asian minorities. The

paper by Patton provides a very useful background to the origins and beliefs of

the Amish, and indicates how their religious principles have influenced development

of the patterns of diagnosis and care for specific genetic disorders prevalent within the

community.

The series of papers by Meyer, Lund, Thong et al., Guhadasan and Pises, and Dave

et al. deal with aspects of medical and community genetics in Saudi Arabia, South

Africa, Malaysia, Cambodia and India. Saudi society is still largely characterized

by clan and tribal loyalties, with marriage usually conducted within the boundaries

of these traditional groupings and consanguineous marriage strongly favoured. Given

the oil wealth of the country, excellent diagnostic and treatment facilities are widely

available, but prenatal testing for the prevention of affected births is precluded by the

conservative interpretation of Islam that prevails within the country. Therefore premarital

screening and genetic counselling are the methods of choice in reducing the incidence of

inherited disorders. Oculocutaneous albinism in the Black populations of Southern Africa

presents a quite different social and medical genetic problem. As outlined by Lund,

improved community education is a major requirement to its solution, not least in

explaining to a couple and their respective families how an albino baby could have

been born to non-affected parents. In economic terms Malaysia does not qualify as a

low income country, but it shares with low income nations a lack of representative

data on the prevalence of genetic diseases. The population-based study of birth defects

conducted by Thong et al. can therefore be seen as the first step in establishing a

Birth Defects Register for Malaysia, and given the ethnic profile of that country it

may also serve as an appropriate interim model for other Asian nations. In contrast,

Cambodia is one of the poorest countries in Asia and diagnostic laboratory facilities

are generally restricted. The paper by Guhadasan and Pises indicates how clinical

acumen is the mainstay for the diagnosis of genetic disorders in a children’s

114 A. H. Bittles & W. N. Erber

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hospital because of the lack of resources and ancillary investigative facilities. However,

even this approach is limited due to the paucity of teaching of genetics in the medical

curriculum. Consequently, in this resource-poor country, major improvements are

needed if awareness of genetic disorders is to be raised. This is an especially urgent

task as within the Southeast Asian region 30–40% of the population are carriers of one

or more haemoglobinopathies. The final paper in this section by Dave et al. provides an

excellent example of primary health care provision in a low income setting, with a

study of mental retardation conducted by trained primary health centre doctors, nurses

and community health volunteers on some 550 000 people living in semi-urban and

slum settlements in Mumbai. As indicated by the authors, their testing protocol could

provide a starting point for comparable programmes in other low income countries,

and it further illustrates the potential importance of non-governmental agencies in

health maintenance in low income countries.

Issues involved in health care provision for genetic disorders in multi-ethnic,

multi-cultural developed societies are considered by Mehta and Saggar in the UK,

and by Saleh et al. in Australia. Recent UK legislation requires that all public authorities

should promote ‘race’ equality and provide fair and accessible patient services within

the National Health Service. But as pointed out by Mehta and Saggar, over 300

languages are now spoken in London alone, which makes the delivery of appropriate

information and genetic counselling in a patient’s mother tongue a near-impossible

task. The scale of the problem may be less acute in Sydney. However, the practical

experience gained by Saleh et al. in devising educational materials on medical genetics

to meet the needs of culturally and linguistically diverse communities should serve

as a valuable and precautionary guide for workers in other countries. Particular

requirements identified as necessary for success include a willingness to respond to

community concerns, and due respect for community contributions in the creation of

educational strategies.

In the last group of three papers, by Emery, Moore et al., and Petterson et al.,

bioinformatics systems are described that assist in the diagnosis of inherited cancers,

and for the compilation of international and state-based disease registers for genetic

disorders. Emery discusses computer decision support initiatives for the assessment

of cancer genetic risks in primary health care, through the provision of a simple

pedigree-drawing software program. This has been applied to the implementation of

clinical guidelines for familial breast and colorectal cancer, and presents individualized

information on breast cancer risks. The paper by Moore et al. describes a database

for the neurodevelopmental disorder Rett syndrome, for use by both health professionals

and the families of affected children, and illustrates the potential for global cooperation.

Although the principal aim of the database is improved clinical understanding of the

disorder, because of the statistical power generated through the large numbers of

cases recruited internationally, more rigorous disease genotype–phenotype correlations

also can be derived. Prevalence estimates for intellectual disability in developed countries

range from 0.5% to 3%, but may be as high as 8% in some low income populations,

yet as indicated by Petterson et al. the cause is unknown in over 50% of cases. The

authors utilized a network of linked databases in Western Australia to help meet

the health and social needs of people with intellectual disability, and the outcomes to

date include identification of the major role of birth defects as comorbidities,

and the challenges presented by the rapidly increasing life expectancy of affected

individuals.

Genetics and Population Health 115

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Given the very diverse nature of the constituent papers in this special issue of Annals, any

attempt to compile a concise summary of the overall content is inappropriate. What does,

however, consistently emerge is the need to investigate, comprehend and appreciate

the unique social, ethnic and religious underpinnings of populations if, in turn,

their demography, their population genetic structure, and hence their burden of genetic

disease is to be better understood. Clearly, it will be some time before most low income

countries can hope to attain the levels of health maintenance and disease prevention

enjoyed by the populations of developed countries. However, some specific, inexpensive

measures that could be readily introduced were identified by the participants of a

recent international Workshop on Genomics and Community Genetics held in PR China

(McElreavey et al. 2005).

It is also probable that the gap in health expectations between developed and

low income countries could, in part, be bridged through the sharing of expertise in

population-wide and community-specific education programmes, and via the dissemina-

tion of data on the prevalence and profiles of genetic disorders. In organizational terms

these programmes could be established as ‘north–south’ initiatives (Weatherall 2005)

with, for example, the two-way transfer of health-based information between the UK

with its large, well-established and well-studied South Asian communities and India,

Pakistan, Bangladesh and Sri Lanka, to the benefit of both sides. Equally, regional

networks, as suggested by Chui (2005) for �-thalassaemia in Southeast Asia, could

provide significant mutual benefits in terms of public education, training and treatment.

For both types of exchange, web-based programmes would be of particular value,

especially given the high level of expertise in information technology that already exists

in many low income countries.

In conclusion, as co-organizers of Genetics and Population Health and co-editors of this

special issue of Annals it is our pleasure to record our sincere thanks to the contributing

authors, and to the major supporters of the Conference who, in alphabetical order,

were: AusAID, BankWest, the Birth Defects Foundation (UK), Edith Cowan University,

Genzyme, Novartis Oncology, the Perth Convention Bureau, the Wellcome Trust, the

Western Australian Centre for Pathology and Medical Research, and our co-sponsors

the World Health Organization. It also is a particular pleasure to express our appreciation

to the Editors of Annals of Human Biology and to Taylor & Francis for the opportunity

to collaborate in the preparation of this special issue.

References

Alwan A, Modell B. 2003. Recommendations for introducing genetic services in developing countries.

Nat Rev Genet 4:1–8.

Chui DHK. 2005. Alpha-thalassaemia and population health in Southeast Asia. Ann Hum Biol 32:123–130,

this issue.

McElreavey K, Wang W, Bittles AH. 2005. First Asian Workshop on Genomics and Community Genetics.

Community Genet, in press.

Pitchappan RM. 2002. Castes, migration, immunogenetics and infectious diseases in South India. Community

Genet 5:157–161.

PRB. 2004. World population data sheet. Washington, DC: Population Reference Bureau.

Weatherall DJ. 2005. The global problem of genetic disease. Ann Hum Biol 32:117–122, this issue.

WHO. 2002. Genomics and world health. Geneva: World Health Organization.

116 A. H. Bittles & W. N. Erber

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