al ▁re cess ive ▁trait . ▁Mut ations ▁of ▁ABC A 3 ▁consist ▁of ▁miss ense , ▁n ons ense , ▁frames h ift , ▁sp lice - cite , ▁insert ion ▁or ▁delet ion . ▁These ▁mut ations ▁are ▁class ified ▁into ▁two ▁types ▁of ▁ABC A 3 ▁mut ations , ▁those ▁that ▁pre clude ▁normal ▁tra ff ick ing ▁of ▁ABC A 3 ▁from ▁ER ▁to ▁l am ell ar ▁memb rane , ▁and ▁those ▁that ▁affect ▁ATP - binding ▁ability ▁of ▁ABC A 3 ▁needed ▁for ▁ph osph ol ip id ▁transport ation . ▁Due ▁to ▁its ▁roles ▁in ▁l am ell ar ▁body ▁bi ogen esis ▁and ▁m atur ation ▁of ▁sur fact ant ▁prote ins , ▁ep ith el ial ▁type ▁II ▁cells ▁with ▁alter ed ▁ABC A 3 ▁exhib it ▁prem ature ▁l am ell ar ▁bodies ▁and ▁dam aged ▁m atur ation ▁of ▁SP - B / SP - C . ▁Sur fact ant ▁samples ▁from ▁patients ▁with ▁ABC A 3 ▁def ic iency ▁do ▁not ▁lower ▁surface ▁t ension ▁as ▁effectively . ▁A ffect ed ▁surface ▁t ension ▁ability ▁results ▁from ▁incomplete ▁formation ▁of ▁l am ell ar ▁bodies , ▁due ▁to ▁lack ▁of ▁li pid ▁infl ux ▁by ▁ABC A 3 . ▁Im mun ost aining ▁of ▁SP - B ▁in ▁ABC A 3 ▁patients ▁show ▁decre ased ▁level ▁of ▁m ature ▁SP - B ▁and ▁imp a ired ▁process ▁of ▁pro SP - B ▁to ▁SP - B , ▁thus , ▁confirm ing