Phenotypes associated with this allele

• Allele Symbol: Fkbp1b^tm1Syf
• Allele Name: targeted mutation 1, Sidney Fleischer
• Allele ID: MGI:2182644
• Summary: 1 genotype

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Fkbp1b^tm1Syf/Fkbp1b^tm1Syf	either: (involves: 129S/SvEv) or (involves: 129S/SvEv * C57BL/6)	MGI:3624028

Genotype
MGI:3624028

hm1

• Allelic Composition: Fkbp1b^tm1Syf/Fkbp1b^tm1Syf
• Genetic Background: either: (involves: 129S/SvEv) or (involves: 129S/SvEv * C57BL/6)

• ♀: phenotype observed in females
• ♂: phenotype observed in males
• N: normal phenotype

cardiovascular system

abnormal interventricular septum morphology ( J:75646 )

♂ • male (but not female) homozygotes display occasional focal disarray in the interventricular septum in the upper region of the heart, suggestive of hypertrophic cardiomyopathy

thick interventricular septum ( J:75646 )

♂ • at 4 months, male (but not female) homozygotes show a 44% increase in the thickness of the interventricular septum relative to wild-type males

increased heart weight ( J:75646 )

♂ • at post-mortem, adult male homozygotes display increased heart weights (30%) and heart weight/body weight ratios (29%) relative to wild-type males, whereas female homozygotes exhibit normal heart weights relative to wild-type females

cardiac hypertrophy ( J:75646 )

♂ • at 4 months, male (but not female) homozygotes exhibit a significant increase in cardiac mass relative to age- and strain-matched wild-type males, despite equivalent alterations in calcium-induced calcium release and Ca²⁺ sparks in males and females

♂ • notably, female homozygotes treated with tamoxifen, an estrogen receptor antagonist, develop cardiac hypertrophy similar to that of male homozygotes

increased heart left ventricle weight ( J:75646 )

♂ • at 4 months, male homozygotes show a 32% increase in the left ventricular mass/body weight ratio, whereas the left ventricular end-diastolic diameter remains unchanged

increased heart left ventricle posterior wall thickness ( J:75646 )

♂ • at 4 months, male (but not female) homozygotes show a 22% increase in the thickness of the left ventricular posterior wall relative to wild-type males

abnormal myocardial fiber physiology ( J:75646 )

• mutant ventricular myocytes display a significantly greater shortening relative to wild-type myocytes (21.0 0.7% vs 10.2 3.0%, respectively), indicating an increase in the net cytosolic Ca²⁺ load during excitation-contraction coupling

• notably, male and female homozygotes exhibit similar dysregulation of Ca²⁺ release, seen as increases in the amplitude, size and duration of Ca²⁺ sparks and calcium-induced calcium release gain

hypertension ( J:75646 )

♂ • at 16-18 weeks of age, male homozygotes exhibit hypertension; in contrast, age-matched female homozygotes are not hypertensive

increased systemic arterial diastolic blood pressure ( J:75646 )

♂ • at 16-18 weeks of age, male homozygotes display increased diastolic pressures relative to wild-type males (111.3 2.7 vs 92.6 4.1 mmHg, respectively)

increased systemic arterial systolic blood pressure ( J:75646 )

♂ • at 16-18 weeks of age, male homozygotes display increased systolic pressures relative to wild-type males (145.1 5.0 vs 124.7 5.4 mmHg, respectively)

growth/size/body

increased heart weight ( J:75646 )

♂ • at post-mortem, adult male homozygotes display increased heart weights (30%) and heart weight/body weight ratios (29%) relative to wild-type males, whereas female homozygotes exhibit normal heart weights relative to wild-type females

cardiac hypertrophy ( J:75646 )

♂ • at 4 months, male (but not female) homozygotes exhibit a significant increase in cardiac mass relative to age- and strain-matched wild-type males, despite equivalent alterations in calcium-induced calcium release and Ca²⁺ sparks in males and females

♂ • notably, female homozygotes treated with tamoxifen, an estrogen receptor antagonist, develop cardiac hypertrophy similar to that of male homozygotes