P011: Marked phenotypic heterogeneity associated with a heterozygous pathogenic variant in the acetyl-CoA acyltransferase 2 gene

Conclusion:This study utilized a large dataset to evaluate associations between IEMs, GA, and BW, and suggests that LCHAD/MTP deficiency is most strongly associated with preterm birth and lower BW.These associations were not observed in other FAO disorders, suggesting an underlying disease mechanism specific to LCHAD/MTP deficiency.The association with preterm birth and lower BW in LCHAD/MTP deficiency may be secondary to the pathophysiology of maternal HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome and maternal acute fatty liver of pregnancy (AFLP), which are also unique features of this FAO disorder.This study more clearly delineates the incidence and degree of prematurity and LBW in LCHAD/MTP deficiency, which will inform future prenatal counseling efforts for at-risk patients and families.The data analyzed in this study did not include gestational nor maternal history data that potentially contributes to these findings; future work is needed to determine if prematurity and LBW are independent findings in LCHAD/MTP deficiency or more commonly observed in cases with significant pregnancy complications, such as HELLP syndrome and/or AFLP.