Thalassemia cannot be prevented, but can be detected prior to birth. As the disease is caused due to mutation in genes, the DNA analysis of the fetus can be done to diagnose the disease.
Can Thalassemia Be Detected Before Birth?
The thalassemia inherits in an autosomal recessive pattern and is considered as genetic disease. The disease is caused due to mutation in the genes. Thus, the disease cannot be prevented but can be managed. Thalassemia can also be detected before birth and the counseling is provided to the patient for interruption of pregnancy in case the fetus suffers from severe form of the disease. Following are the detection techniques of thalassemia that can be used to detect thalassemia prior to birth:
Carrier Screening: Thalassemia is the disease which is caused due to the gene mutation. It is an inherited disease in which the mutant gene is present in the parents. Thus, if the symptoms are not present in the parents and the mutated gene is present in them, they are said to be the carrier of the disease. Thus, carrier screening can be done to estimate the occurrence of thalassemia in the progeny. If both the parents are carrier, the chances of having a normal baby is 25%, chances of having a carrier is 50% and chances of having baby with severe thalassemia is 25%. Thus, through carrier screening, production for thalassemia can be done.
Preimplantation Diagnosis: With the advent of new technologies such as in vitro fertilization and embryo transfer, it is possible to detect the disease prior to implantation and development of fetus. Pre-implantation genetic diagnosis can be done to detect the presence of thalassemia. The amplification of the genome of blastomere is done prior to testing the present of abnormal gene. The technique used for this purpose is Polymerase Chain Reaction (PCR). The pre-implantation diagnosis is an important, non-invasive and rapid method to detect the presence of thalassemia. This is important in reducing the cases of interruption of pregnancy coupled with moral and ethical dilemma.
Prenatal Diagnosis: The concept of prenatal diagnosis for thalassemia was originated in 1970s when the fetal blood was obtained through aspiration and the globin chain synthesis was performed. After that, the technology has taken a leap forward and through sophisticated DNA analysis, the prenatal diagnosis has significantly improved. The technique used in the diagnosis is Polymerase chain reaction (PCR). Under this technique the methods used are Reverse Oligonucleotide-probe analysis and Amplification Refractory Mutation System. The presently adopted method for taking the sample is the chorionic villi method, taken in the early weeks of pregnancy. It is generally used transabdominally due to low risk of infection.
Counseling And Interruption Of Pregnancy: When through any of the diagnostic technique it has been found that the fetus is at the risk of suffering from thalassemia or conclusively suffering from thalassemia, counseling is provided to the couples. If both the parents are carrier and they are planning to have a baby, the risks and symptoms of thalassemia are described, and they are advised to drop their plan. Further, if the diagnosis of the disease is confirmed in the prenatal diagnosis, the parents are counseled for interruption of pregnancy. The interruption of pregnancy can be done, keeping in context, the applicable law related to medical termination of pregnancy in that particular country.
The prognosis of the disease depends upon the severity of the disease, fewer the number of genes mutated, less severe the disease and more the chances of survival. The patient with thalassemia minor or trait does not have any symptom and did not require any treatment unless iron deficiency is conclusively diagnosed. The prognosis of such patients is good. The severe form of the disease, thalassemia major, causes severe form of anemia. Prognosis of such patients is poor as they develop various complications later in life.
Various methods used for diagnosis of thalassemia prior to birth are per natal diagnosis, carrier screening, and pre-implantation diagnosis. The technique used for DNA analysis is Polymerase chain reaction.
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