Phenotypes associated with this allele

• Allele Symbol: Npr2^slw
• Allele Name: short-limbed dwarfism
• Allele ID: MGI:3774275
• Summary: 2 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Npr2^slw/Npr2^slw	involves: C57BL/6 * DDY	MGI:3806086
ht2	Npr2^cn/Npr2^slw	involves: AKR/J * C57BL/6 * DDY	MGI:3806088

Genotype
MGI:3806086

hm1

• Allelic Composition: Npr2^slw/Npr2^slw
• Genetic Background: involves: C57BL/6 * DDY

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

mortality/aging

postnatal lethality, incomplete penetrance ( J:163374 )

• most mice die before weaning

embryonic lethality, incomplete penetrance ( J:129973 )

• lower than expected number of affected individuals are found in litters of heterozygote parents suggesting that some affected individuals die in utero or after birth

growth/size/body

small nasal bone ( J:129973 )

• nasal length is slightly reduced

meteorism ( J:163374 )

• intestine becomes distended with gas

decreased body length ( J:129973 )

• mice are significantly shorter starting at 3 days of age

• differences become more obvious as the mice get older

• the average length of adult mice is 70-80% of age-matched wild-type controls

disproportionate dwarf ( J:129973 )

• abnormal endochondral ossification leads to a short-limbed dwarfism phenotype

skeleton

enlarged interparietal bone ( J:129973 )

• interparietal bone is slightly larger than wild-type mice

small supraoccipital bone ( J:129973 )

• occurs in adult mice

enlarged parietal bone ( J:129973 )

• parietal bone is slightly larger than wild-type mice

small nasal bone ( J:129973 )

• nasal length is slightly reduced

domed cranium ( J:129973 )

• mice have a slightly domed head by 7 days of age

• the skulls of adult mice are reduced in size along the anterior-posterior axis but are slightly longer along the other two axes

chondrodystrophy ( J:129973 )

• the femur and humerus are severely shortened due to improper ossification

• the tibia, fibula, radius and ulna are slightly affected

• at P7, the epiphyseal growth plate is slightly lower with decreased numbers of proliferating and hypertrophic chondrocytes

• the hypertrophic chondrocytes present are smaller in length

• at P21, the growth plate is further reduced in size

abnormal endochondral bone ossification ( J:129973 )

• all skeletal bones formed by endochondral ossification are smaller

limbs/digits/tail

short tail ( J:129973 )

• found in mice by 7 days of age

craniofacial

enlarged interparietal bone ( J:129973 )

• interparietal bone is slightly larger than wild-type mice

small supraoccipital bone ( J:129973 )

• occurs in adult mice

enlarged parietal bone ( J:129973 )

• parietal bone is slightly larger than wild-type mice

small nasal bone ( J:129973 )

• nasal length is slightly reduced

domed cranium ( J:129973 )

• mice have a slightly domed head by 7 days of age

• the skulls of adult mice are reduced in size along the anterior-posterior axis but are slightly longer along the other two axes

digestive/alimentary system

abnormal pyloric sphincter morphology ( J:163374 )

• pylorus is markedly narrowed

• random smooth muscle alignment unlike controls where smooth muscle fibers align in one direction.

abnormal digestive system physiology ( J:163374 )

impaired gastric peristalsis ( J:163374 )

• milk is retained in the stomach

abnormal intestine physiology ( J:163374 )

• intestine becomes distended with gas

meteorism ( J:163374 )

• intestine becomes distended with gas

muscle

abnormal pyloric sphincter morphology ( J:163374 )

• pylorus is markedly narrowed

• random smooth muscle alignment unlike controls where smooth muscle fibers align in one direction.

impaired muscle relaxation ( J:163374 )

• pylorus and large intestine fail to relax in response to the application oc C-type natriuretic factor (CNP)

respiratory system

small nasal bone ( J:129973 )

• nasal length is slightly reduced

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
acromesomelic dysplasia, Maroteaux type		DOID:0080050	OMIM:602875	J:129973

Genotype
MGI:3806088

ht2

• Allelic Composition: Npr2^cn/Npr2^slw
• Genetic Background: involves: AKR/J * C57BL/6 * DDY

growth/size/body

disproportionate dwarf ( J:129973 )

• abnormal endochondral ossification leads to a short-limbed dwarfism in mice confirming the "slw" mutation is an allele of the Npr2 gene locus