▁delay , ▁possible ▁breath ing ▁problems ▁of ▁epis od ic ▁hyper vent ilation ▁and / or ▁breath - hold ing ▁while ▁aw ake , ▁rec urrent ▁se iz ures / ep ile ps y , ▁g astro int est inal ▁issues , ▁and ▁distinct ive ▁fa cial ▁features . ▁S tere ot yp ic ▁movements , ▁particularly ▁of ▁the ▁arms , ▁w rist s ▁and ▁fingers ▁are ▁almost ▁universal . ▁Hyp ot onia ▁is ▁common ▁( 7 5 % ), ▁as ▁is ▁an ▁un st ead y ▁g ait . ▁Other ▁features ▁include ▁a ▁single ▁( sim ian ) ▁pal mar ▁cre ase , ▁long , ▁sl ender ▁fingers , ▁flat ▁feet ▁and ▁crypt orch id ism ▁( in ▁males ). ▁The ▁presence ▁of ▁" f etal ▁finger ▁p ads " ▁is ▁common . ▁Hyper vent ilation ▁may ▁occur ▁and ▁is ▁sometimes ▁followed ▁by ▁ap nea ▁and ▁cy anos is . ▁Const ip ation ▁is ▁common . ▁Micro ce ph aly ▁and ▁se iz ures ▁may ▁occur . ▁Hyp op ig ment ed ▁skin ▁mac ules ▁have ▁occasionally ▁been ▁reported . ▁Ind ividual s ▁with ▁Pitt – H op kins ▁synd rome ▁typically ▁have ▁a ▁happy , ▁exc itable ▁de mean or ▁with ▁frequent ▁sm iling ▁and ▁laugh ter . ▁ ▁Gen et ics ▁ ▁The ▁condition ▁was ▁first ▁described ▁in ▁ 1 9 7 8 ▁by ▁Pitt ▁and ▁Hop kins ▁in ▁two ▁un related ▁patients . ▁ ▁The ▁gen etic ▁cause ▁of ▁this ▁dis order ▁was ▁described ▁in ▁ 2 0 0