Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P00492 (hypoxanthine-guanine phosphoribosyltransferase)
 2,385 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chorionic villi were sampled at 8-9 weeks' gestation in four women whose fetuses were at risk for Lesch-Nyhan syndrome. Radiochemical assay of hypoxanthine phosphoribosyl transferase activity and fetal sexing (in two fetuses by means of a Y chromosome specific cDNA probe) showed that three fetuses were affected. The biochemical findings were confirmed after therapeutic abortion in two cases and spontaneous abortion in the third. Chorion biopsy and ultramicroscale enzymology may be a suitable alternative to recombinant-DNA-based methods for first-trimester diagnosis in selected diseases where the abnormal gene product is an enzyme expressed in the chorion by the 8th week of pregnancy.
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PMID:First-trimester diagnosis of Lesch-Nyhan syndrome. 615 Feb 36

At this time a rather large number of congenital abnormalities still occur. About 2-3% of pregnancies will result in children with major congenital abnormalities that cannot be detected prenatally. Yet, with the availability of prenatal diagnosis for an ever increasing number of genetic problems and, more recently, for developmental problems as well, a new option was offered to couples at risk when they took the risk of pregnancy: finding out whether the fetus was abnormal. An early argument regarding the ethics of this option was formulated by Dan Callahan, director of the Hastings Institute for Ethics, Society and the Life Sciences, when he indicated the need to be careful about the term "option." A need exists to be careful about societal pressures in favor of the new medical options--on, for example, a pregnant woman who is over 35 and does not get a prenatal diagnosis; or on a woman carrying a Down's syndrome child identified by prenatal diagnosis not to have an abortion. This was the 1st specter raised when prenatal diagnosis was introduced. The most common indication for amniocentesis is the risk of chromosomal abnormalities. The risk of discovering a chromosomal abnormality by amniocentesis is about double the risk at birth because a number of chromosomally abnormal fetuses are lost late in the 2nd trimester by spontaneous abortion. The age cutoff at 35 raises an immediate ethical question: since the total number of births to women over age 35 seems to be increasing, and at the same time a greater and greater percentage of children with Down's syndrome are born to women under age 35, the question arises as to whether amniocentesis should be done on all pregnancies, and whether all births with Down's syndrome should be selectively aborted or avoided. Amniocentesis in all pregnancies is impractical at this time from the technological and the cost perspective, but the ethical question should be raised. Among the X-linked disorders, 1 group cannot be specifically diagnosed in utero by prenatal diagnosis. If a woman is known to be a carrier, her daughters won't have the disease, but half of them will be carriers. Regarding sex preference as a reason for amniocentesis, all the geneticist can and should do is provide a couple with a base of knowledge and understanding of the options available to them and the outcome of each option. X-linked disorders such as hemophilia and Lesch-Nyhan syndrome and the autosomal recessive biochemical disorders or inborn errors of metabolism such as Tay-Sachs disease and over 100 others can now be diagnosed prenatally. In the vast majority of cases, amniocentesis is performed because the parents already have an abnormal child. Screening programs for Tay-Sachs disease, for sickle cell anemia, and for thalassemia also detect couples at risk. A variety of tools other than amniocentesis are now available for prenatal diagnosis. Much work is being conducted in the prenatal diagnosis of sickle cell anemia and thalassemia.
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PMID:Genetics, amniocentesis, and abortion. 660 72