• homozygotes die prior to E10.5; at this stage, 44% of mutant embryos are resorbed

• litter size from heterozygous breeding pairs averages 6.2 2.0 relative to 10.8 2.0 for heterozygous male wild-type female crosses

• heterozygotes show no significant differences in body weight, plasma insulin, glucose levels during fasting or after a glucose challenge, insulin-stimulated glucose uptake in soleus muscle and adipocytes, and insulin-inhibited lipolysis in adipocytes relative to wild-type mice

• fewer mutants than predicted are seen at P10, however observe no deaths between P1 and P10, indicating embryonic lethality or death soon after birth

• develop myocardial hypertrophy

• exhibit semilunar valve enlargement resulting from over-abundant mesenchymal cells, however atrioventricular valves and interventricular septum are unaffected

• valve abnormalities persist into adulthood causing mild to moderate aortic stenosis

• aortic valve is thickened

• pulmonary valve is thickened

• valve abnormalities persist into adulthood causing moderate to severe regurgitation

• elevation in left-ventricular-end-diastolic pressures, reflecting diastolic dysfunction and possibly incipient heart failure

• higher peak left ventricular systolic pressure and a trend towards increased +dP/dT

• severe conduction system abnormalities

• slightly prolonged QRS

• prolonged ST interval

• occasionally show cardiac dilation characteristic of congestive heart failure

• display defective eyelid closure