An Appraisal of Genetic Studies on Leprosy

Abstract

SummaryThe present paper reviews the research lines which have been explored to evaluate to what extent genetic factors are intervening on the mechanism of resistance and susceptibility to leprosy.It presents a critical discussion of the investigations on the familial association of leprosy, familial association of leprosy types, intrafamilial contagion of leprosy, concordance of leprosy in twinpairs, racial differences on leprosy prevalence and lepromatous rate, pedigree studies, association of leprosy to genetic markers, Australia antigen, and dermatoglyphic patterns. Space was also allotted to review family and twin-pair studies on the Mitsuda reaction, as well as to the investigation on the in vitro behaviour of blood macrophages against killed M. leprae.Some areas in which further research on leprosy and genetics may be considered as prioritary are outlined with some detail.

Estudo epidemiológico de 107 focos familiares de hanseníase no município de Duque de Caxias - Rio de Janeiro, Brasil

“…Beiguelman (1972) 1 observed that, in families in which the father and the mother were virchowian, relatives related by blood had a higher risk of developing the same polar type of the disease. In addition, the author noticed that the risk of contracting other forms of the disease was higher in non-consanguineous members of the household.…”

“…2 The development of methods of segregation analysis made possible the investigation about the role of hereditarianism in familial aggregation to establish the form of inheritance. 3,4 In 1979, Smith studied 91 families from the Philippines and verified that virchowian leprosy was three times more prevalent when one of the parents presented this clinical form of the disease, as compared to when none of them presented this form of the disease or presented no disease whatsoever. Nonetheless, the author argues that the multifactorial hypothesis correlates better with epidemiological data than any type of Mendelian inheritance.…”

Genetic factors in leprosy: a study of children in Uganda

“…For the children with visiting contact, the summed rate for those having only a e " -t%s-if (Beiguelman, 1972) showed that, in families in an endemic area, the recurrence of leprosy cases was non-random. He also demonstrated a familial association in the type of leprosy manifested, whether lepromatous or tuberculoid, as had previously been found by Dungal and Spickett (quoted in Spickett, 1964).…”

“…These have included studies of blood group, atypical enzymes, G6PD deficiency, taste sensitivity to phenylthiourea, and HLA antigens (Beiguelman, 1972;Vogel, 1968;Thomas & Job, 1972;De Vries et al 1976;World Health Organization, 1970). The results are in some instances controversial, but together they point towards a definite genetic influence on susceptibility to leprosy.…”

“…Since the ability to develop lepromatous leprosy may be a genetically transmitted character (Beiguelman, 1972;Newell, 1966), it would be of interest to study this in a population with a higher proportion of lepromatous cases.…”