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  • Abnormal: Differing from normal.
  • Accumulation: The process of acquiring more or the build-up of a substance.
  • Amino Acids: Amino acids combine to form proteins and when proteins are digested amino acids remain – amino acids are either essential (obtained through the diet) or non-essential (made by the body from the essential amino acids).
  • Ammonia: A product of protein digestion.
  • Amniocytes: Cells in the amniotic fluid surrounding the fetus before birth.
  • Amniotic Fluid: The fluid surrounding the fetus inside the uterus.
  • Analysis: Examination to discover characteristics or meanings.
  • Anorexia: Loss of appetite.
  • Arginine: Non-essential amino acid (made only by the urea cycle).
  • Argininosuccinate or Argininosuccinic Acid: A molecule made by the urea cycle.
  • Aspartate: Non-essential amino acid (made only by the urea cycle).
  • Assay: Assessment of characteristics (as weight, measure, or quality).
  • Athetosis: Repeated slow movements especially of the arms and legs due to brain dysfunction.
  • Autosomal Recessive Inherited Disorder: Two copies of an abnormal gene inherited from both parents that is capable of producing disease, specifically on one of 22 pairs of autosomes (non-sex linked).
  • Autosomes: Any of the non-sex determining chromosomes.