▁causes ▁both ▁beta - g lo bin ▁sub un its ▁of ▁hem og lo bin ▁to ▁change ▁into ▁hem og lo bin S ▁( H b S ). ▁ ▁S ick le ▁cell ▁an emia ▁is ▁a ▁ple iot rop ic ▁disease ▁because ▁the ▁expression ▁of ▁a ▁single ▁mut ated ▁H BB ▁gene ▁produces ▁numerous ▁consequences ▁throughout ▁the ▁body . ▁The ▁mut ated ▁hem og lo bin ▁forms ▁polym ers ▁and ▁cl umps ▁together ▁causing ▁the ▁de ox y gen ated ▁sick le ▁red ▁blood ▁cells ▁to ▁assume ▁the ▁dis fig ured ▁sick le ▁shape . ▁As ▁a ▁result , ▁the ▁cells ▁are ▁inf lex ible ▁and ▁cannot ▁easily ▁flow ▁through ▁blood ▁vessels , ▁increasing ▁the ▁risk ▁of ▁blood ▁cl ots ▁and ▁possibly ▁dep riv ing ▁vital ▁org ans ▁of ▁o xygen . ▁Some ▁comp lications ▁associated ▁with ▁sick le ▁cell ▁an emia ▁include ▁pain , ▁dam aged ▁org ans , ▁stro kes , ▁high ▁blood ▁pressure , ▁and ▁loss ▁of ▁vision . ▁S ick le ▁red ▁blood ▁cells ▁also ▁have ▁a ▁short ened ▁lif es pan ▁and ▁die ▁prem ature ly . ▁ ▁Mar fan ▁synd rome ▁▁ ▁Mar fan ▁synd rome ▁( M FS ) ▁is ▁an ▁aut os om al ▁dominant ▁dis order ▁which ▁affect s ▁ 1 ▁in ▁ 5 – 1 0 , 0 0 0 ▁people . ▁M FS ▁ar ises ▁from ▁a ▁mut ation ▁in ▁the ▁FB N 1 ▁gene , ▁which ▁enc odes ▁for ▁the ▁g ly cop rote in ▁f ibr ill in -