TLDR Most Hairless gene mutations reduce its ability to work with the Vitamin D Receptor, which might explain a certain type of hair loss.
The document from August 1, 2007, investigated the interaction between the Vitamin D Receptor (VDR) and mutants of the Hairless (HR) gene, which is associated with atrichia with papular lesions (APL), a form of hair loss. The study found that most pathogenic HR mutants lost their corepressor activity on VDR, which could be due to impaired interactions with histone deacetylase 1 (HDAC1). However, one mutant, E583V, retained normal activity, suggesting it may not be pathogenic. HR variants from non-synonymous polymorphisms showed normal or partially reduced corepressor activity. All pathogenic mutants and variants increased the level of VDR protein when coexpressed, indicating that this HR function was not affected by the mutations. The study provided insight into the molecular basis of APL by showing how HR mutations impact VDR corepressor activity.
74 citations,
September 2006 in “Cell Cycle” The HR protein's role as a repressor is essential for controlling hair growth.
19 citations,
May 2006 in “Clinical and Experimental Dermatology” Researchers found a new mutation causing total hair loss from birth.
81 citations,
January 2006 in “Journal of cellular physiology” Mice without the vitamin D receptor gene lose hair due to disrupted hair follicle cycles.
78 citations,
November 2005 in “Endocrinology” Hairless protein can block vitamin D activation in skin cells.
137 citations,
September 2005 in “Proceedings of the National Academy of Sciences of the United States of America” The HR protein helps hair grow by blocking a hair growth inhibitor, aiding in hair follicle regeneration.
26 citations,
October 2002 in “Journal of Investigative Dermatology” 
57 citations,
April 2002 in “The journal of investigative dermatology/Journal of investigative dermatology” Vitamin D receptor is crucial for starting hair growth after birth.
15 citations,
April 2002 in “British Journal of Dermatology” Hairless gene not strongly linked to baldness.
139 citations,
September 2001 in “The journal of investigative dermatology/Journal of investigative dermatology” Mutations in the Vitamin D receptor gene can cause hair loss similar to mutations in the Hairless gene.
14 citations,
July 2001 in “American Journal of Human Genetics” Haplogroup X found in Altaian population supports Amerindian origin.
13 citations,
November 2013 in “Journal of Endocrinology/Journal of endocrinology” Vitamin D receptor helps control hair growth genes in skin cells.
158 citations,
August 2011 in “Reviews in endocrine and metabolic disorders” Vitamin D and its receptor regulate skin functions like cell growth, immunity, hair cycle, and tumor prevention.
76 citations,
January 2010 in “Journal of bone and mineral metabolism” 62 citations,
January 2009 in “Biochemistry” Vitamin D receptor binds similarly to natural and synthetic ligands, affecting gene regulation.
271 citations,
September 2008 in “Nutrition reviews” Vitamin D receptor interacts with certain dietary components to help prevent diseases and regulate hair growth.
42 citations,
July 2007 in “Journal of Biological Chemistry” Most Hairless gene mutations reduce its ability to work with the Vitamin D Receptor, which might explain a certain type of hair loss.
