ly ▁pack ed ▁internal ▁environment ▁of ▁sur fact ant ▁lip ids ▁and ▁sur fact ant ▁prote ins . ▁Mut ations ▁in ▁ABC A 3 ▁cause ▁failure ▁in ▁l am ell ar ▁body ▁synth esis ▁and ▁result ▁in ▁decre ased ▁production ▁of ▁sur fact ant , ▁along ▁with ▁def ic iency ▁of ▁SP - B ▁and ▁SP - C . ▁▁ ▁Sur fact ant ▁met abol ism ▁d ys function ▁is ▁a ▁condition ▁where ▁pul mon ary ▁sur fact ant ▁is ▁ins u fficient ▁for ▁ade qu ate ▁resp iration . ▁ ▁C ause ▁Sur fact ant ▁met abol ism ▁d ys function ▁describes ▁a ▁group ▁of ▁d ys functions ▁caused ▁by ▁different ▁mut ations ▁in ▁sur fact ant ▁related ▁gen es . S ever e ▁def ic iency ▁of ▁pul mon ary ▁sur fact ant ▁due ▁to ▁dist urbed ▁met abol ism ▁of ▁any ▁of ▁these ▁prote ins ▁can ▁lead ▁to ▁some ▁form ▁of ▁inter st it ial ▁lung ▁disease ▁in ▁new born s ▁and ▁adult s . ▁These ▁conditions ▁share ▁similar ▁path oph ys i ology ▁and ▁over la pping ▁phen ot ypes ▁because ▁sur fact ant ▁gene ▁products ▁interact ively ▁communicate ▁and ▁control ▁one ▁another . ▁Thus , ▁d ys function ▁of ▁a ▁sur fact ant ▁protein , ▁or ▁rel ating ▁protein , ▁generates ▁def ic ien cies ▁of ▁others . ▁ ▁SF TP B ▁mut ations ▁ ▁Most ▁disease - ca using ▁mut ations ▁in ▁SF TP B ▁result ▁in ▁a ▁complete ▁lack ▁of ▁m ature ▁SP - B ▁protein