17-ketosteroids and Genetic-Diseases--Inborn

Practical and scientific aspects of prenatal detection of genetic disorders is discussed. The indications for intrauterine detection of familial biochemical and particular chromosomal disorders require assessment of the risks of transabdominal amniocentesis and of the reliability of diagnosis. A high degree of experience in cultivating amniotic fluid cells and in performing diagnostic tests is required. The obstetrician performing the amniocentesis should be responsible for referring the family to a physician who will perform the abortion. A high-risk group for which amniocentesis may be especially important includes families in which 1 parent is a carrier of a chromosomal rearrangement and in which the woman is a known carrier of an X-linked recessive disorder so that sex determination is important. A moderate-risk group includes women who become pregnant after age 40 in which the risk of having a child with a chromosomal aberration is greater than 1%. A low-risk group includes women over 35 and women who have previously borne a child with trisomic Down's syndrome. The experience gained in over 300 patients suggests that transabdominal aminocentesis carries minimal risks to mother and fetus. Analyses of amniotic fluid obtained by amniocentesis have resulted in antenatal diagnoses of Pompe's disease (deficient alpha-1, 4-glucosidase), Tay-Sachs disease (deficient hexosaminidase A), mucopolysaccharidosis (quantitative and qualitative changes in mucopolysaccharides), methylmalonic aciduria (increased methylamlonate), and adrenogenital syndrome (increase 17-ketosteroids and pregnanetriol). There is a lack of consensus on the reliability of several of these diagnoses resulting from the direct analysis of amniotic fluid. Analyses of uncultured amniotic fluid cells have resulted in diagnoses of Pompe's disease (ultrastructural changes) and Tay-Sachs disease. Analyses of cultivated amniotic fluid cells have enabled diagnoses of galactosemia (deficient galactose-1-phosphate uridyl transferase), X-linked uric aciduria (by autoradiography), lysosomal acid phosphatase deficiency, metachromatic leukodystrophy (deficientaryl sulfatase A), mucopolysaccharidosis, cystic fibrosis (metachromatic granules), and Marfan's syndrome (metachromatic granules). Methylmalonic aciduria has been detected in utero by marternal methymalonate excretion. Adrenogenital syndrome has been detected by urinary estriol.

Topics: 17-Ketosteroids; Amniocentesis; Amnion; Amniotic Fluid; Chromosome Aberrations; Chromosome Disorders; Eugenics; Female; Fetal Diseases; Genetic Diseases, Inborn; Humans; Pregnancy; Punctures