Autosomal recessive disorders are genetic disorders in which the trait is controlled by a recessive allele on the autosome. If the causative gene for the disease is recessive and located on the autosomes, the disease does not develop in the heterozygous state due to the normal dominant gene, and only develops when the causative gene is pure. In autosomal recessive disorders, the traits expressed in the offspring may not be expressed in the parents, i.e. the child has symptoms that the parents do not necessarily have. Heterozygotes who do not exhibit clinical symptoms but carry the disease-causing gene are called carriers, and their disease-causing gene can be passed on to offspring. The onset of the disease is characterized by an equal chance of disease in men and women, with both parents often being disease-free but carriers of the recessive gene. One quarter of the siblings are affected, one quarter are normal, and one half are carriers. The children of patients do not usually develop the disease. Therefore, transmission from one generation to another is not seen in the family line and cases tend to be disseminated. However, after consanguineous marriage, the risk of recessive disease in the offspring is significantly higher than in random marriages.