They're used by the cells of our body for many different types of processes and many different types of reactions. Now, there are many examples of different types of diseases that are a result of abnormalities that exist on either the genes of the chromosomes or the chromosomes themselves. So in this lecture, we're going to focus on a specific type of genetic disease, genetic disorder known as autosomal recessive disease. Now, before we examine four specific examples of human autosomal recessive diseases, let's actually recall and define what we mean by an autosomal recessive disease in the first place. Well, recall that in every single somatic cell of the human body, we have 23 pairs of homologous chromosomes. One of these pairs is known as the sex chromosomes.