MMP9 and Stillbirth: Missense actin mutations in FLNB leading to atelosteogenesis type I [37] and lethal skeletal dysplasia or inhibition of ERK/MMP-2 and MMP-9 pathways that are critical for trophoblast invasion [38], may be possible mechanisms of potentially lethal de novo FLNB SNVs in stillbirth etiology [39].