Overexpression of β- and γ-subunits causes worsening of mucoobstructive lung phenotype. Semiquantitative histopathology scores for mice from the congenic β × γENaC-Tg cross at PND35. At all airway levels probed, i.e., hilum (A, level 1), 2 mm caudal to the hilum (B, level 2), and 4 mm caudal to the hilum (C, level 3), βγENaC-Tg mice exhibited more severe airway mucous cells, air space enlargement, and airway inflammation compared with βENaC-Tg littermates; n = 8–10 mice/genotype. ANOVA *P < 0.05 vs. WT mice; #P < 0.05 vs. βENaC-Tg mice.