And so what we mean by an autosomal recessive disease is that genetic abnormality exists on one of the genes or both of the genes on the autosomal homologous chromosome pair. So this is a type of abnormality that exists on autosomes and not on sex chromosomes. So let's actually define what we mean by recessive disease. So a disease is said to be recessive if only the homozygous recessive individual, the homozygous recessive genotype actually creates that particular phenotype for that particular disease. So a disease is autosomal recessive, if only the homozygous recessive individual for that particular trait expresses that phenotype for that disease. And the genetic abnormality exists on the autosome and not on the sex chromosome.