Defective ABCA3 causes SMDP3

ATP-binding cassette sub-family A member 3 (ABCA3) plays an important role in the formation of pulmonary surfactant, probably by transporting phospholipids such as phosphatidylcholine (PC) and phosphatidylglycerol (PG) from the ER membrane to lamellar bodies (LBs). PC and PG are the major phospholipid constituents of pulmonary surfactant. LBs are the surfactant storage organelles of type II epithelial cells from where phospholipids can be secreted together with surfactant proteins (SFTPs) into the alveolar airspace. Defects in ABCA3 can cause pulmonary surfactant metabolism dysfunction type 3 (SMDP3; MIM:610921), resulting in respiratory distress in newborns and interstitial lung disease (ILD) in children (Whitsett et al. 2015).

ATP结合盒亚家族A成员3（ABCA3）在肺泡表面活性物质的生成过程中扮演着至关重要的角色，其作用可能在于通过转运磷脂类物质，如磷脂酰胆碱（PC）和磷脂酰甘油（PG），从内质网膜运输至亚单位体（LBs）。PC和PG是肺泡表面活性物质的主要磷脂成分。亚单位体是II型上皮细胞的表面活性物质储存细胞器，其中磷脂可以与表面活性蛋白（SFTPs）一同分泌至肺泡间隙。ABCA3的缺陷可导致肺泡表面活性物质代谢障碍型3（SMDP3；MIM:610921），进而引发新生儿呼吸窘迫症以及儿童间质性肺疾病（ILD）（Whitsett等，2015年）。