Phenotypes associated with this allele

• Allele Symbol: Ntrk1^tm1Bbd
• Allele Name: targeted mutation 1, Mariano Barbacid
• Allele ID: MGI:1888374
• Summary: 2 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Ntrk1^tm1Bbd/Ntrk1^tm1Bbd	involves: 129S2/SvPas	MGI:2175185
hm2	Ntrk1^tm1Bbd/Ntrk1^tm1Bbd	involves: 129S2/SvPas * C57BL/6	MGI:3704860

Genotype
MGI:2175185

hm1

• Allelic Composition: Ntrk1^tm1Bbd/Ntrk1^tm1Bbd
• Genetic Background: involves: 129S2/SvPas

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

mortality/aging

premature death ( J:17194 )

• no homozygotes survive beyond P55

postnatal lethality, incomplete penetrance ( J:17194 )

• although normal at birth, about 50% of homozygotes die by P20

growth/size/body

decreased body size ( J:17194 )

• at P10, homozygotes are noticeably smaller than wild-type mice

behavior/neurological

unresponsive to tactile stimuli ( J:17194 )

• at p10, homozygotes fail to react to deep pinpricks in the their whisker pads and rear paws

abnormal vibrissae reflex ( J:17194 )

• at P10, homozygotes fail to orient in response to vibrissal stimulation

increased thermal nociceptive threshold ( J:17194 )

• at P10, homozygotes remain on a hot plate at 60 degrees Celsius for at least 10 sec, whereas wild-type and heterozygous mice jump off within 1-2 sec

nervous system

abnormal sympathetic ganglion morphology ( J:17194 )

• at P0, a number of sympathetic ganglia display neuronal loss

small superior cervical ganglion ( J:17194 )

• at P0, superior cervical ganglia (SCG) show neuronal loss as well as pyknotic nuclei, suggesting cellular degeneration

• by P10, the SGC is severely shrunken

abnormal cholinergic neuron morphology ( J:17194 )

• adult homozygotes display a reduction in the cholinergic basal forebrain projections to the hippocampus and cerebral cortex

small trigeminal ganglion ( J:17194 )

• at P0, trigeminal ganglia are significantly smaller and the number of trigeminal neurons is reduced by 70-90%

• other cranial ganglia appear normal

small dorsal root ganglion ( J:17194 )

• at P0, dorsal root ganglia show a 70-90% loss of neurons; small-sized neurons are preferentially lost

abnormal sympathetic nervous system physiology ( J:17194 )

• upon eye illumination, the iris constricts without efficient redilation, indicating that the parasympathetic component of the oculomotor nerve is intact but the sympathetic innervation from the superior cervical ganglion is defective

• in contrast, the facial, acoustic and glossopharyngeal nerves function normally

pigmentation

mottled coat ( J:17194 )

• at >3-4 weeks of age, homozygotes display a mottled fur

vision/eye

miotic pupil ( J:17194 )

• by P20, surviving homozygotes have myotic pupils

corneal opacity ( J:17194 )

• at >3-4 weeks, corneal opacities are observed

blepharoptosis ( J:17194 )

• by P20, surviving homozygotes exhibit slight ptosis

limbs/digits/tail

abnormal digit morphology ( J:17194 )

• at >3-4 weeks, digits are missing, probably due to self-mutilation

ulcerated autopod ( J:17194 )

• at >3-4 weeks, homozygotes display ulcerated paws

integument

mottled coat ( J:17194 )

• at >3-4 weeks of age, homozygotes display a mottled fur

skin lesions ( J:17194 )

• at >3-4 weeks of age, homozygotes develop multiple scabs all over their body

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
hereditary sensory neuropathy		DOID:0050548	OMIM:PS162400	J:17194

Genotype
MGI:3704860

hm2

• Allelic Composition: Ntrk1^tm1Bbd/Ntrk1^tm1Bbd
• Genetic Background: involves: 129S2/SvPas * C57BL/6

hearing/vestibular/ear

hearing/vestibular/ear phenotype ( J:41896 )

N • at P1, newborn homozygotes exhibit normal neuron numbers in cochlear and vestibular ganglia as well as normal innervation patterns of cochlear and vestibular sensory epithelia relative to wild-type mice