Procedure for removing amniotic fluid surrounding the developing fetus in order to test the fluid or cells within the fluid.
Dark-staining body in the nuclei of female mammals that contains a condensed, inactive X chromosome.
Heterozygous individual who has no apparent abnormality but can pass on an allele for a recessively inherited genetic disorder.
chorionic villus sampling (CVS)
Prenatal test in which a sample of chorionic villi cells is removed for diagnostic purposes.
Variation in regard to the normal number of chromosomes inherited or in regard to the normal sequence of alleles on a chromosome.
Change in chromosome structure in which the end of a chromosome breaks off, or two simultaneous breaks lead to the loss of an internal segment.
Duchenne muscular dystrophy
Chronic progressive disease affecting the shoulder and pelvic girdles, commencing in early childhood; transmitted as an X-linked trait, and affected individuals, predominantly males, rarely survive to maturity.
Fragile X syndrome
Genetic disease that results in a constellation of abnormalities due to a trinucleotide repeat expansion.
Chromosomes arranged by pairs according to their size, shape, and general appearance in mitotic metaphase.
Alleles of different genes that are located on the same chromosome and tend to be inherited together.
Failure of homologous chromosomes or daughter chromosomes to separate during meiosis I and meiosis II, respectively.
Chromosome that determines the sex of an individual; in humans, females have two X chromosomes, and males have an X and a Y chromosome.
Allele that occurs on the sex chromosomes but may control a trait having nothing to do with the sexual characteristics of an individual.
Group of symptoms that appear together and tend to indicate the presence of a particular disorder.
Movement of a chromosomal segment from one chromosome to another, nonhomologous chromosome, leading to abnormalities.