A study of 240 patients with Gaucher Disease found that 12% of alleles at GBA1 were recombinant alleles, most arising from gene conversion, nonreciprocal recombination that contributes short tracts of unidirectional sequence, or reciprocal recombination producing larger structural variation (e.g., deletion events) through nonallelic homologous recombination (NAHR) (Tayebi et al., 2003). The gene discussed is GBA1; the disease is Gaucher disease.