A family study of lymphedema of the leg in a lymphatic filariasis-endemic area.

The risk of filarial lymphedema may not be equivalent for all members of filaria-exposed populations. While evidence for a genetic factor that influences acquisition of infection has been growing, very little work has addressed whether there is a genetic basis to the development of disease due to lymphatic filariasis. We designed a family study of lymphedema in a rural community in Haiti to assess disease aggregation. Three hundred sixty-eight female patients sixteen years of age or older were enrolled at a lymphedema treatment clinic between June 1995 and December 1999. After applying additional eligibility criteria, 172 probands were enrolled into the family study for detailed pedigree collection between September 1998 and December 1999. Fifty-three lymphedema cases were identified among the probands' parents, full-siblings, children, half-siblings, and mating partners of the parents. Twelve of the 53 cases were among males. The proportion of cases occurring in a biologic parent of the proband was higher than in unrelated individuals married into the proband's family (P = 0.0010). This is the first large family study based on pedigrees to assess the familial aggregation of lymphedema due to filariasis. This family study will be useful to investigate the role of genes and environment in the development of filarial-related lymphedema.