The Tay-Sachs disease was named after a British ophthalmologist, Warren Tay and New York Neurologist, Bernard Sachs (Desnick & Kaback, 2001). This paper delves into the Tay-Sachs disease, analyze the case study of peter and Rita and give genetic advice to the two in regard to the unborn baby who is infected with the disease
It is an inherited disorder and it destroys the neurons in the brain as well as the spinal cord. It mainly affects infants who look normal from birth (Freedman, 2009). Tay-Sachs disease is a genetic lipid disorder whereby harmful quantities of fatty substance (ganglioside GM2) build up in tissues as well nerve cells in the brain and it is caused by insufficient activity of beta-hexosaminidase A enzyme that basically catalyzes the biodegradation of acidic fatty materials (Tay-Sachs Disease - Genetics Home Reference, (n,d).
Tay-Sachs disease is a recessive genetic disease and a baby has to receive a defective recessive gene from both parents to develop this condition. An infant who inherits one copy of the defective gene will not have the disease but will be a carrier (Freedman, 2009).
Discussion on Peter and Rita’s case
The maternal grandparents of Rita were not affected nor were they carriers of the gene that causes Tay-Sachs disease. This is because her maternal grandparent had three children who are living, two girls and her mother is alive and well. On the other hand, the paternal grandparents were carriers. This is because their son died of an unknown disease. The other son who is living is Rita’s father and he is a carrier of Tay Sachs disease. The son who dies had two recessive genes that were inherited from both paternal grandparents. In this case, Rita inherited this defective gene from his x- chromosome from her father who inherited it from Rita’s paternal grandparents. So Rita inherited a defective gene from her father (Freedman, 2009).
On the case of Peter, both maternal and fraternal grandparents were carriers of the Tay Sachs disease. That is why peter’s mother, who is a carrier, died of pancreatic cancer that was inherited from the deceased parents who might have died of the same disease. Peter’s father is a carrier who inherited the defective gene from the paternal grandparents. The paternal grandparent had two children whereby one had both two recessive genes and hence died while the other son who is peter’s father was a carrier who inherited one defective gene and one normal gene. This defective gene was inherited by peter from his father (Freedman, 2009).
Peter and Rita are therefore carriers of the genes and this implies that the probability of them getting a normal offspring who is a carrier is one out of four and it is equivalent to that of getting an offspring who is completely affected. This offspring will die because of the recessive genes inherited from both parents while the probability of getting a carrier baby is half (Freedman, 2009).
Rita and Peter are advised not to carry out an abortion, because three quarters of his of their babies will survive while only one will die at an earlier age. They are also advised that they inherited the disease from their fathers who were carriers.