Autozygosity mapping, first suggest by Lander and Botstein, is the method of choice for the discovery of autosomal recessive gene loci.2 The methodology seeks homozygous regions in consanguineous families. The greater the number of affected individuals who have a shared homozygous region and the greater the size of the region, the more likely it is to harbour the mutation that causes the disease. Mueller and Bishop modelled the use of a single multi-affected family and suggested that this was the most efficient strategy to determine a disease locus, particularly given the complexities of genetic heterogeneity.3 Autozygosity mapping became practical with the discovery of multiple highly polymorphic microsatellite repeat markers spread throughout the genome.4 Most researchers currently use optimised panels of approximately 400 markers for an initial genome-wide screen for linkage, giving 10–12 cM coverage of the autosomal genome; a process that has lead to the discovery of many recessive loci.5