TLDR  Mutations in hKAP1 genes may cause hereditary hair disorders.   
  The study characterized the human keratin-associated protein 1 (hKAP1) family, identifying eight hKAP1 genes with unique pentapeptide repeat structures in the repetitive I domain, which likely defined their functional characteristics. These genes were thought to have arisen through gene duplication and mutations. Expression studies showed that hKAP1 mRNAs were predominantly expressed in the cortical layer of human scalp hair. The research suggested that mutations in hKAP genes could be linked to hereditary hair disorders, similar to known mutations in hair keratin genes causing monilethrix. The findings emphasized the importance of further analysis of hKAP genes to understand hair characteristics and disorders.
            98 citations
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  June 2001   in “Journal of biological chemistry/The Journal of biological chemistry”
           98 citations
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  June 2001   in “Journal of biological chemistry/The Journal of biological chemistry”    A cluster of sulfur-rich hair protein genes was found on chromosome 17.  
               22 citations
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  August 1999   in “Mechanisms of Development”    Pmg-1 and Pmg-2 are new genes important for skin and mammary gland development.  
      12 citations
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  February 1998   in “Gene”
           12 citations
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  February 1998   in “Gene”    The B2 genes are crucial for hair growth in rats.  
      25 citations
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  May 1994   in “Journal of Investigative Dermatology”
           25 citations
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  May 1994   in “Journal of Investigative Dermatology”    Researchers found a new gene, hacl-1, that is active in mouse hair follicles during hair growth and may be important for hair biology.  
      48 citations
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  July 1993   in “The journal of investigative dermatology/Journal of investigative dermatology”
           48 citations
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  July 1993   in “The journal of investigative dermatology/Journal of investigative dermatology”    Hair growth is controlled by specific gene clusters and proteins, and cysteine affects hair gene expression in sheep.  
               67 citations
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  December 1990   in “The journal of cell biology/The Journal of cell biology”    Researchers found genes for cysteine-rich proteins that form the protective layer of hair in humans and sheep.  
    
  
        
        71 citations
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  August 2005   in “The journal of investigative dermatology. Symposium proceedings/The Journal of investigative dermatology symposium proceedings”
           71 citations
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  August 2005   in “The journal of investigative dermatology. Symposium proceedings/The Journal of investigative dermatology symposium proceedings”    Hair keratin-associated proteins are essential for strong hair, with over 80 genes showing specific patterns and variations among people.  
               48 citations
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  November 2002   in “Journal of biological chemistry/The Journal of biological chemistry”    Genetic variations in hair keratin proteins exist but don't significantly affect hair structure.  
               53 citations
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  June 2005   in “The journal of investigative dermatology/Journal of investigative dermatology”    KAP genes show significant genetic variability, but its impact on hair traits is unclear.  
      98 citations
,
  June 2001   in “Journal of biological chemistry/The Journal of biological chemistry”
           98 citations
,
  June 2001   in “Journal of biological chemistry/The Journal of biological chemistry”    A cluster of sulfur-rich hair protein genes was found on chromosome 17.  
      27 citations
,
  June 2005   in “The journal of investigative dermatology/Journal of investigative dermatology”
           27 citations
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  June 2005   in “The journal of investigative dermatology/Journal of investigative dermatology”    The study found that variations in hair protein genes are likely due to evolutionary deletions or duplications.