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Phenotypes Associated with This Genotype
Genotype
MGI:2676545
Allelic
Composition
Chrdtm1Emdr/Chrdtm1Emdr
Genetic
Background
either: B6SJL.129-Chrdtm1Emdr or (involves: 129S1/Sv * 129X1/SvJ * C57BL/6J * SJL/J)
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Chrdtm1Emdr mutation (1 available); any Chrd mutation (33 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
mortality/aging
• 86% of homozygotes are still alive at E14.5; however, a sharp increase in lethality is noted after E14.5
• only 49% (95 out of 194) of homozygotes are recovered at birth
• a few attempt, unsuccessfully, to inflate their lungs
• most are still born due to cardio-respiratory failure
• 12% of homozygous mutant embryos are resorbed at E8.5 (50 out of 57 expected)
• no homozygotes with an abnormal allantois survive past E8.5

embryo
• at E10.5, homozygotes show absence of neural crest cell migration through the peripharyngeal region into the proximity of the heart, resulting in lack of outflow tract septation
• at E8.5, 4 of 50 homozygotes show early ventralization of the mesoderm, with increased extraembryonic mesodermal cells noted in the allantois
• at E8.5, 4 of 50 homozygotes display a reduced body size
• at E8.5, 4 of 50 homozygotes display a reduced embryonic region, while the remaining 46 appear morphologically normal
• at E9.0, the second (hyoid) pharyngeal arch is absent
• in addition, pharyngeal arches three to six fail to form
• at E8.5, 4 of 50 homozygotes display absence of trunk mesoderm
• at E8.5, 4 of 50 homozygotes exhibit a significantly hypoplastic and poorly differentiated neural plate
• at E8.5, 4 of 50 homozygotes display absence of a notochord
• homozygotes that die perinatally show absence of an anterior notochord at E14.5
• at E9.5, the pharyngeal pouches are reduced to a single swelling in the anterior-most region
• at E8.5, 4 of 50 homozygotes display absence of somites
• at E8.5, 4 of 50 homozygotes display an enlarged allantois with an abundance of extraembryonic mesodermal cells

craniofacial
• newborn homozygotes display fused basioccipital and basisphenoid bones while the alisphenoid appears normal
• at E14.5, the basioccipital and basisphenoid cartilages are fused; the ossification centre of the basioccipital is narrower and extends into the basisphenoid
• newborn homozygotes display a hypoplastic presphenoid bone
• newborn homozygotes lack the squama temporalis
• newborn homozygotes a smaller temporal bone
• newborn homozygotes display a shorter zygomatic arch
• newborn homozygotes exhibit hyoid bone hypoplasia
• newborn homozygotes lack the coronoid, condylar and angular processes
• newborn homozygotes lack the angular process
• newborn homozygotes lack the condylar process
• newborn homozygotes lack the coronoid process
• newborn homozygotes display an abnormally small jaw
• newborn homozygotes lack a secondary palate
• at E9.0, the second (hyoid) pharyngeal arch is absent
• in addition, pharyngeal arches three to six fail to form
• the palatal shelves fail to extend medially to form the secondary palate
• newborn homozygotes have external ears that are set abnormally close to the eyes
• newborn homozygotes exhibit small external ears

cardiovascular system
• at E14.5, homozygotes exhibit an enlarged anterior spinal artery
• in newborns, the pulmonary arteries originate directly from the proximal truncus arteriosus, resulting in the absence of a common pulmonary trunk
• at birth, part of the aortic arch is absent
• depending of the laterality of the descending aorta, the right or left subclavian arteries adopt an abnormal retrooesophageal position
• 40% of newborn homozygotes display an abnormal right-turning aortic arch; the descending aorta is placed on the right side of the esophagus and the left subclavian runs posterior to it
• absence of the brachiocephalic artery
• in newborns, the common carotid arteries directly join the truncus arteriosus, resulting in the absence of the brachiocephalic artery and part of the aortic arch
• at E14.5, homozygotes exhibit persistent truncus arteriosus
• at E14.5, homozygotes exhibit severe hemorrhage

skeleton
• newborn homozygotes display fused basioccipital and basisphenoid bones while the alisphenoid appears normal
• at E14.5, the basioccipital and basisphenoid cartilages are fused; the ossification centre of the basioccipital is narrower and extends into the basisphenoid
• newborn homozygotes display a hypoplastic presphenoid bone
• newborn homozygotes lack the squama temporalis
• newborn homozygotes a smaller temporal bone
• newborn homozygotes display a shorter zygomatic arch
• newborn homozygotes exhibit hyoid bone hypoplasia
• newborn homozygotes lack the coronoid, condylar and angular processes
• newborn homozygotes lack the angular process
• newborn homozygotes lack the condylar process
• newborn homozygotes lack the coronoid process
• newborn homozygotes display an abnormally small jaw
• newborn homozygotes display reduced laryngeal cartilages
• newborn homozygotes exhibit cricoid cartilage hypoplasia
• newborn homozygotes exhibit thyroid cartilage hypoplasia
• newborn homozygotes lack the anterior arch of the atlas
• at E14.5, homozygotes display underdeveloped vertebral neural arches
• newborn homozygotes exhibit reduced vertebral bodies, with delayed ossification and occasional loss of other elements of the vertebrae e.g. spinous processes, neural arches and the anterior arch of the atlas

hearing/vestibular/ear
• newborn homozygotes have external ears that are set abnormally close to the eyes
• newborn homozygotes exhibit small external ears
• at E9.0, otic vesicles are reduced to half their normal diameter
• a conspicuous indentation is noted in the neck region
• newborn homozygotes display a malformed and reduced otic capsule
• newborn homozygotes exhibit hypoplasia/absence of the inner ear
• at E14.5, homozygotes exhibit absence of the Eustachian tube
• newborn homozygotes display a malformed tympanic ring
• newborn homozygotes display a reduced tympanic ring

endocrine/exocrine glands
• newborn homozygotes lack parathyroid glands (derivatives of pharyngeal pouches 3 and 4)
• newborn homozygotes lack a thymus (a derivative of the third pharyngeal pouch)
• newborn homozygotes exhibit a thyroid gland of irregular shape
• newborn homozygotes display thyroid hypoplasia

nervous system
• at E8.5, 4 of 50 homozygotes exhibit a significantly hypoplastic and poorly differentiated neural plate
• at E9.5, homozygotes display severe cranial sensory ganglia abnormalities, including loss of epibranchial placode-derived ganglia
• at E9.5, the vestibulocochlear ganglia are deformed and displaced
• at E9.5, the geniculate ganglion is either extremely reduced or entirely absent
• at E9.5, the petrosal ganglion is either extremely reduced or entirely absent
• at E9.5, the petrosal ganglion is either extremely reduced or entirely absent
• at E9.5, the trigeminal ganglia are deformed and displaced
• at E9.5, the nodose ganglion is either extremely reduced or entirely absent
• at E9.5, the nodose ganglion is either extremely reduced or entirely absent

respiratory system
• newborn homozygotes display reduced laryngeal cartilages
• newborn homozygotes exhibit cricoid cartilage hypoplasia
• newborn homozygotes exhibit thyroid cartilage hypoplasia
• newborn homozygotes exhibit malformations in the oropharynx region
• at E14.5, homozygotes exhibit a significantly reduced pharynx
• at E9.5, homozygotes display a reduction of pharyngeal endoderm
• newborn homozygotes display a reduced tracheal size

hematopoietic system
• newborn homozygotes lack a thymus (a derivative of the third pharyngeal pouch)

homeostasis/metabolism
• newborn homozygotes appear cyanotic
• at E14.5, homozygotes exhibit severe edema

digestive/alimentary system
• newborn homozygotes lack a secondary palate
• the palatal shelves fail to extend medially to form the secondary palate
• newborn homozygotes lack an esophagus

growth/size/body
• newborn homozygotes lack a secondary palate
• the palatal shelves fail to extend medially to form the secondary palate
• newborn homozygotes have external ears that are set abnormally close to the eyes
• newborn homozygotes exhibit small external ears
• at E8.5, 4 of 50 homozygotes display a reduced body size
• newborn homozygotes display microcephaly
• newborn homozygotes are slightly smaller than wild-type littermates

immune system
• newborn homozygotes lack a thymus (a derivative of the third pharyngeal pouch)

muscle

cellular
• at E10.5, homozygotes show absence of neural crest cell migration through the peripharyngeal region into the proximity of the heart, resulting in lack of outflow tract septation


Contributing Projects:
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB), Gene Ontology (GO)
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last database update
09/10/2019
MGI 6.14
The Jackson Laboratory