TLDR  Mutations in the DSG4 gene can cause a rare hair disorder similar to monilethrix.   
  Researchers identified novel compound heterozygous mutations in the DSG4 gene in a Japanese patient with congenital hypotrichosis, initially diagnosed as monilethrix due to a similar hair-shaft abnormality. The maternal allele had an S192P transition, and the paternal allele had a 2039insT mutation, leading to unstable transcripts. These findings suggested that mutations in DSG4 could cause monilethrix-like congenital hypotrichosis and proposed an overlap between localized autosomal recessive hypotrichosis (LAH) and monilethrix.
            28 citations
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  October 2004   in “Differentiation”
           28 citations
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  October 2004   in “Differentiation”    A gene deletion causes the "hairless" trait in Iffa Credo rats.  
               50 citations
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  February 2004   in “Genomics”    A gene mutation causes lanceolate hair in rats by disrupting hair shaft integrity.  
               37 citations
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  June 2000   in “Experimental dermatology”    The Lanceolate hair-J mutation in mice mimics human hair disorders like Netherton's syndrome.  
               235 citations
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  July 1999   in “Journal of biological chemistry/The Journal of biological chemistry”    Human hair is made up of different keratins, some strong and some weak, with specific types appearing at various stages of hair growth.  
      74 citations
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  October 1998   in “Journal of biological chemistry/The Journal of biological chemistry”
           74 citations
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  October 1998   in “Journal of biological chemistry/The Journal of biological chemistry”    The 190-kbp domain contains all human type I hair keratin genes, showing their organization and evolution.  
               36 citations
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  July 1996   in “The journal of investigative dermatology/Journal of investigative dermatology”    Mice with the 'lanceolate hair' mutation have abnormal hair and skin similar to human Netherton's syndrome.  
    
  
        
      19 citations
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  May 2004   in “The American Journal of Dermatopathology”
           19 citations
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  May 2004   in “The American Journal of Dermatopathology”    The research found that a specific gene mutation causes fewer hair follicles and disrupted hair growth cycles, leading to thin and short hair in people with Hypotrichosis with Juvenile Macular Dystrophy.