tokens: While its functional role has become much clearer in the recent years , how mutations in the MBTPS2 gene lead to several human disorders with different phenotypes including Ichthyosis Follicularis , Atrichia and Photophobia syndrome ( IFAP ) with or without BRESHECK syndrome , Keratosis Follicularis Spinulosa Decalvans ( KFSD ) , Olmsted syndrome , and Osteogenesis Imperfecta type XIX remains obscure .