Fig. 2.

Cardiac phenotype is likely the cause of the premature death of Burgheron mutants. Echocardiography was performed longitudinally from 25 to 120 d of age on mutants (n = 17) and wild-type (n = 14) mice. At the time of the analysis, mutants were separated into “short-lived” (n = 7) and long-lived (n = 10) cohorts depending on whether they had died before or after 89 d of age. (A) Heart rate. (B) Left ventricle mass normalized to BW. (C) EF (A–C, Dunnett’s multiple comparison tests to the wild-type group). (D) Representative ultrasound images of the left ventricle of a mutant (Bottom) and control littermate (Top) at P35. (E) Representative hematoxylin/eosin staining of sagittal cross-sections of the heart of control (Left) and mutant (Right) mice at P35. The heart of the mutant mice was observed on animals euthanized for humane reasons, within less than a day before anticipated spontaneous death. [Scale bar, (D and E) 1 mm.]