Step 1: Phenomenon Leading to XO Abnormality.
The phenomenon that leads to an XO chromosomal abnormality is Turner Syndrome. This occurs when there is a missing or incomplete second sex chromosome (only one X chromosome is present instead of two).
Step 2: Symptoms of XO Chromosomal Abnormality.
Individuals with Turner syndrome typically have short stature, infertility, and may experience heart defects, kidney problems, and learning difficulties. They also typically lack the development of secondary sexual characteristics such as breast development.
Step 3: Karyotype.
The karyotype of individuals with Turner syndrome is 45,X, which means they have a total of 45 chromosomes instead of the normal 46, with only one X chromosome instead of two sex chromosomes.