Phenotypic female lacking one X chromosome, the genotype being designated XO.
Note: This results in a number of developmental abnormalities including short stature, webbed neck, sexual immaturity, and sterility.
Source: PAC, 2016, 88, 713. (Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)) on page 816 [Terms] [Paper]