The use of conjunctival biopsy and enzyme analysis in tears for the diagnosis of homozygotes and heterozygotes with Fabry disease.

In most inborn errors of metabolism, the detection of heterozygotes is either impossible, or is feasible only on a statistical basis, so that some uncertainty always remains in that diagnosis. Heterozygote detection is by far more imperative in sex-linked diseases than in autosomal recessive disorders. Indeed, female carriers are at risk of having affected children whatever is the genome of their husband. The method we describe realizes the secure detection of heterozygotes in Fabry disease. It combines the ultrastructural examination of conjunctival biopsies and the assay of thermolabile alpha-galactosidase in tears. The technique is harmless and relatively simple: Both biopsy and tear collection were performed at home in most of the subjects.