Incidence and prevalence of Huntington's disease in Malta : a methodological discussion

Abstract

Introduction: Huntington's disease (HD) is an autosomal dominant neurodegenerative condition with an average prevalence of between 4 and 8 per 100,000. Limited research in Malta indicates a higher prevalence. However, no formal epidemiological study has ever been done. Methods: The primary limitation at present is the lack of an adequate patient database. Various methodologies to determine incidence and prevalence are discussed. Different approaches include: making HD a notifiable condition, the snowball sampling technique and the cross-sectional approach. Prospective molecular genetic analysis of cord blood for the CAG repeat size in the Huntingtin gene may be used to give an estimate of the incidence of HD in Malta. The size of the CAG repeats in the Huntingtin gene may be studied and the mean size compared to that in other European countries in order to identify whether Malta has a higher norm for CAG repeats. This could be combined with haplotyping techniques which could confirm the presence of a founder effect. Conclusion: Estimation of the frequency of HD in Malta will require the use of multiple epidemiological and molecular genetic techniques. The advantages and limitations of each, together with a synergistic combination of techniques, will be presented in the light of various ethical and humanistic problems that will arise and which have to be overcome for such a study to be successful. Epidemiological knowledge of HD would direct public health efforts in supporting and highlighting the plight of HD sufferers.