Primordial dwarfism (PD) is characterized by global growth failure,both during embryogenesis and postnatally.Loss-of-function germline mutations in La ribonucleoprotein domain family,member 7 (LAPR7) have recently been linked to PD.Paradoxically,LARP7 deficiency was previously assumed to be associated with increased cell growth and proliferation via activation of positive transcription elongation factor b (P-TEFb).Here,we show that Larp7 deficiency likely does not significantly increase P-TEFb activity.