Phenotypes Associated with This Genotype

Genotype
MGI:3044676

• Allelic Composition: Gamt^tm1Isb/Gamt^tm1Isb
• Genetic Background: involves: 129S1/Sv * 129X1/SvJ

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

mortality/aging

postnatal lethality ( J:90367 )

• fewer than expected homozygous mice are found after birth and those that died had no milk in their stomachs

adipose tissue

decreased total body fat amount ( J:90367 )

• total body fat is reduced to less than 30% of control littermates

behavior/neurological

decreased grip strength ( J:90367 )

• maximum grip force is decreased in homozygous males

limp posture ( J:90367 )

• when lifted by the tail homozygous mice display reduced body tension

cellular

oligozoospermia ( J:90367 )

♂ • mature spermatozoa are almost absent and elongated spermatid numbers are greatly reduced

multinucleated giant male germ cells ( J:90367 )

♂

abnormal mitochondrial ATP synthesis coupled electron transport ( J:90367 )

• ATP synthase activities are significantly higher in brains from homozygous mice

endocrine/exocrine glands

abnormal seminiferous tubule morphology ( J:90367 )

♂ • the seminiferous tubules are highly unordered with large numbers of resorption holes, increased lumen size, and many multinucleated giant cells

growth/size/body

increased percent water in carcass ( J:90367 )

• water content normalized to total body weight is increased 20% compared to control littermates

decreased body weight ( J:90367 )

• decreased body weight in homozygous mice is detectable during the first weeks of life and this difference compared to wild-type littermates increases over time

• this decrease in body weight is not the result of reduced food intake, altered cage activity or changes in secretion of leptin, adiponectin, or insulin

homeostasis/metabolism

decreased creatine level ( J:90367 )

• creatine concentrations are significantly reduced in serum, brain, muscle and urine samples

decreased circulating creatine level ( J:90367 )

• creatine concentrations are significantly reduced in serum

decreased urine creatine level ( J:90367 )

• creatine concentrations are significantly reduced in urine samples

abnormal amino acid level ( J:90367 )

• guanidinoacetate, a metabolite used to generate creatine, concentrations are increased in serum, brain, and urine samples

decreased circulating creatinine level ( J:90367 )

• creatinine concentrations are significantly reduced in serum, brain, muscle and urine samples

abnormal urine amino acid level ( J:90367 )

• guanidinoacetate, a metabolite used to generate creatine, concentrations are increased in urine samples

decreased urine creatinine level ( J:90367 )

• creatinine concentrations are significantly reduced in urine samples

renal/urinary system

abnormal urine amino acid level ( J:90367 )

• guanidinoacetate, a metabolite used to generate creatine, concentrations are increased in urine samples

decreased urine creatinine level ( J:90367 )

• creatinine concentrations are significantly reduced in urine samples

reproductive system

oligozoospermia ( J:90367 )

♂ • mature spermatozoa are almost absent and elongated spermatid numbers are greatly reduced

multinucleated giant male germ cells ( J:90367 )

♂

abnormal seminiferous tubule morphology ( J:90367 )

♂ • the seminiferous tubules are highly unordered with large numbers of resorption holes, increased lumen size, and many multinucleated giant cells

male infertility ( J:90367 )

♂ • many matings of homozygous males produce no litters

reduced male fertility ( J:90367 )

♂ • when males are fertile they tend to produce smaller litters

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
guanidinoacetate methyltransferase deficiency		DOID:0050799	OMIM:612736	J:90367