mortality/aging
• Background Sensitivity: only about 2.6% of homozygotes are born alive on an outbred genetic background; in contrast, no born homozygotes are identified out of 129/Sv inbred offspring
• all naturally born homozygotes (about 2.6%) die within 4 weeks, with most deaths occurring by P21
• similarly, all rescued homozygotes die within 5 weeks, with no survivors identified at P35
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• only 5% of homozygotes are recovered at E15.5; only 2.6% of pups born are homozygous
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• ~90% of homozygotes die between E11.5 and E15.5, apparently of cardiovascular failure
• treatment of pregnant females at stage E8.5 of pregnancy with 0.25 mg/ml of L-DOPA rescues ~50% of homozygotes to E17.5 or birth, whereas 1 mg/ml of L-DOPA rescues all homozygotes to birth
• treatment of pregnant females with 1 mg/ml of L-DOPA from E10.5 to E13.5, results in only partial rescue in utero, suggesting a continuous requirement for catecholamines
• treatment of pregnant females with 0.5 mg/ml of DOPS only partially rescues homozygotes to birth, suggesting a requirement for dopamine in addition to noradrenaline
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cardiovascular system
• at E12.5-E15.5, 6 of 14 homozygotes display congestion of blood in the liver and major blood vessels
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• at E12.5-E15.5 in 6 of 14 homozygotes
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• at E12.5, ventricular cardiomyocytes appear less organized
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• at E12.5, ventricular cardiomyocytes appear more vacuolated
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• at E12.5, homozygotes with dilated atria exhibit thinning of the atrial wall
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• at E12.5, 2 of 3 homozygotes display significantly dilated atria
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• at E12.5, homozygotes display slight bradycardia relative to wild-type embryos (37.9 7.5 bpm vs 44.7 9.0 bpm, respectively)
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growth/size/body
• all homozygotes that survive to term display normal birth weights but become severely runted by P7; similar runting in noted in rescued homozygotes
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• by P15, surviving homozygotes weigh ~40% of wild-type littermates
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behavior/neurological
• at P15, surviving homozygotes fail to balance on a rotating pencil or walk up an incline
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liver/biliary system
• at E12.5-E15.5 in 6 of 14 homozygotes
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