Whatley Whatley SD SD Ducamp Ducamp S S Gouya Gouya L L C-terminal deletions in the ALAS2 gene lead to gain of function and cause X-linked dominant protoporphyria without anemia or iron overload C-terminal deletions in the ALAS2 gene lead to gain of function and cause X-linked dominant protoporphyria without anemia or iron overload Am J Hum Genet Am J Hum Genet 2008 2008 83 83 408 408 414 414 10.1016/j.ajhg.2008.08.003 10.1016/j.ajhg.2008.08.003 18760763 18760763. This evidence concerns the gene ALAS2 and Tangier disease.