Complex sentence: As advances in genetic technology have enabled a precise delineation of the various chromosome 18 abnormalities, the phrase "de Grouchy syndrome" has fallen out of favor because it not adequately describe the full spectrum of chromosome 18 deletions.
Split into simpler sentences: As advances in genetic technology have enabled a better delineation of chromosome 18 abnormalities, the phrase "de Grouchy syndrome" has fallen out of favor. The phrase "de Grouchy syndrome" does not adequately describe the full spectrum of chromosome 18 deletions.