Hemophilia, Klinefelter syndrome and canavan disease are examples of genetic diseases, note Mayo Clinic, WebMD and Genetics Home Reference. Canavan disease impairs the working ability of neurons in the brain, leading to ineffective transmission of impulses, explains Genetics Home Reference. The most severe form of the disease affects children and is unnoticeable until they are about 5 months old, when symptoms begin to appear. The disease’s milder form affects juveniles and causes symptoms such as delayed motor skills or speech.
Deficiency in clotting factors, platelets or plasma proteins, causes hemophilia. Up to 70 percents of patients with the disease have a family history of the condition. Classification of the disease depends on the clotting factor that is absent in the body. Mothers pass the defective gene located on the X chromosome that causes hemophilia A or B to boys, reports Mayo Clinic. Hemophilia C occurs when either parent passes the gene an unborn boy or girl.
Klinefelter syndrome affects male children born with extra X chromosomes, which results in unusual physical traits that include wide hips and sparse hair growth or enlarged breasts. Most patients affected by the disorder are unaware of their condition, which affects one in 1,000 males, according to WebMD. Uneven splitting of the female egg or male sperm results in the syndrome.