▁suffering ▁from ▁ca ud al ▁regression ▁synd rome ▁can ▁experience ▁a ▁varying ▁degree ▁of ▁the ▁ab normal ity ▁r anging ▁from ▁partial ▁lack ▁of ▁the ▁tail ▁b one ▁and ▁pel vis ▁to ▁more ▁significant ▁cases ▁where ▁there ▁may ▁be ▁par al ysis ▁and , ▁as ▁a ▁result , ▁in hib ited ▁function ▁in ▁the ▁bow el ▁and ▁bl ad der . ▁ ▁This ▁ab normal ity ▁can ▁be ▁caused ▁by ▁the ▁ca ud al ▁cell ▁mass ▁not ▁developing ▁properly ▁due ▁to ▁impro per ▁different iation , ▁and ▁it ▁can ▁lead ▁to ▁sac ral ▁ag en esis , ▁which ▁is ▁one ▁of ▁the ▁hall marks ▁of ▁ca ud al ▁regression ▁synd rome . ▁ ▁Another ▁class ▁of ▁ab normal ities ▁from ▁ca ud al ▁cell ▁mass ▁development ▁includes ▁ca ud al ▁d ys gen esis , ▁which ▁refers ▁to ▁ab normal ities ▁where ▁the ▁sac rum ▁may ▁be ▁de formed ▁or ▁absent , ▁or ▁ab normal ities ▁in ▁which ▁the ▁sp inal ▁cord ▁and ▁the ▁complement ary ▁organ ▁systems ▁may ▁be ▁mal formed . ▁Some ▁of ▁the ▁ab normal ities ▁that ▁fall ▁under ▁this ▁class ▁includes ▁curr ar ino ▁synd rome ▁and ▁sir en om elia . ▁These ▁gen etic ▁defect s ▁were ▁found ▁to ▁have ▁a ▁much ▁higher ▁rate ▁of ▁inc idence ▁in ▁birth s ▁to ▁moth ers ▁with ▁gest ational ▁di ab etes . ▁This ▁tr end ▁may ▁be ▁due ▁to ▁the ▁in hib ition ▁of ▁critical ▁elements ▁of ▁morph ogen esis , ▁that ▁are ▁found ▁in ▁the ▁ext rac ell ular