Congenital baldness caused by an abnormality of the hairless gene.
Note: It may include loss of hair in early childhood, which never regrows.
Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 728 (https://doi.org/10.1515/pac-2015-1202)