Despite mitochondrial morphologic imbalances in both β-Mfn1+/−Mfn2KO and β-Mfn1KOMfn2+/− mice, only β-Mfn1+/−Mfn2KO mice developed glucose intolerance and impaired GSIS similar to that of β-Mfn1/2DKO mice (Fig. 4c, d). The gene discussed is MFN1; the disease is Glucose intolerance.