Phenotypes associated with this allele

• Allele Symbol: Crebbp⁺
• Allele Name: wild type
• Allele ID: MGI:2158255
• Summary: 13 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
ht1	Crebbp^tm1Reck/Crebbp^+	involves: 129P2/OlaHsd	MGI:2679423
ht2	Crebbp^tm2Pkb/Crebbp^+	involves: 129P2/OlaHsd * C57BL/6	MGI:3626195
ht3	Crebbp^tm1.1Ltz/Crebbp^+	involves: 129P2/OlaHsd * C57BL/6N	MGI:3057012
ht4	Crebbp^tm1.1Ltz/Crebbp^+	involves: 129P2/OlaHsd * C57BL/6N * CD-1	MGI:3057013
ht5	Crebbp^tm1Dli/Crebbp^+	involves: 129S6/SvEvTac * C57BL/6	MGI:2175794
ht6	Crebbp^tm1Sis/Crebbp^+	involves: BALB/cCrSlc * C57BL/6NCrlj * CBA/JNCrlj	MGI:3588514
ht7	Crebbp^Gt(U-San)112Imeg/Crebbp^+	involves: C57BL/6 * CBA	MGI:2175792
ht8	Crebbp^tm1Sis/Crebbp^+	involves: C57BL/6NCrlj * CBA/JNCrlj	MGI:2175796
ht9	Crebbp^tm1Few/Crebbp^+	Not Specified	MGI:3046632
cx10	Crebbp^tm2Pkb/Crebbp^+ Ep300^tm3Pkb/Ep300^+	involves: 129P2/OlaHsd * 129S6/SvEvTac * C57BL/6	MGI:3626197
cx11	Crebbp^tm2Pkb/Crebbp^+ Ep300^tm3Pkb/Ep300^tm3Pkb	involves: 129P2/OlaHsd * 129S6/SvEvTac * C57BL/6	MGI:3626199
cx12	Crebbp^tm2Pkb/Crebbp^+ Tg(IghMyc)22Bri/0	involves: 129P2/OlaHsd * C57BL/6 * SJL	MGI:3626200
cx13	Crebbp^tm1Dli/Crebbp^+ Ep300^tm1Dli/Ep300^+	involves: 129S4/SvJae * 129S6/SvEvTac * C57BL/6	MGI:3512279

Genotype
MGI:2679423

ht1

• Allelic Composition: Crebbp^tm1Reck/Crebbp⁺
• Genetic Background: involves: 129P2/OlaHsd

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

mortality/aging

lethality throughout fetal growth and development, incomplete penetrance ( J:85949 )

• about 10% of embryos die between E12.5 and E15.5

postnatal lethality ( J:85949 )

postnatal lethality, complete penetrance ( J:85950 )

• neonates do not survive beyond 1 or 2 days following birth

embryonic lethality during organogenesis, incomplete penetrance ( J:85949 )

• about 10% of embryos die between E12.5 and E15.5

cardiovascular system

thin ventricle myocardium compact layer ( J:85949 )

• compact layer of the ventricles is moderately thinner than in wild-type

abnormal heart development ( J:85949 )

• less severe than in Ep300^tm1Reck heterozygotes

muscle

muscle phenotype ( J:85950 )

N • mutants appear to have normal myogenesis

thin ventricle myocardium compact layer ( J:85949 )

• compact layer of the ventricles is moderately thinner than in wild-type

Genotype
MGI:3626195

ht2

• Allelic Composition: Crebbp^tm2Pkb/Crebbp⁺
• Genetic Background: involves: 129P2/OlaHsd * C57BL/6

mortality/aging

preweaning lethality, incomplete penetrance ( J:103607 )

• there is a decrease of ~30% in number of heterozygotes seen at adulthood compared to expected

Genotype
MGI:3057012

ht3

• Allelic Composition: Crebbp^tm1.1Ltz/Crebbp⁺
• Genetic Background: involves: 129P2/OlaHsd * C57BL/6N

mortality/aging

premature death ( J:93192 )

• reduced survival is seen and this allele could not be backcrossed into C57BL/6N, however backcrossing into CD-1 produces viable offspring

growth/size/body

decreased body size ( J:93192 )

• mutants are very small compared to wild-type littermates

nervous system

abnormal nervous system morphology ( J:93192 )

• neurological abnormalities are seen

Genotype
MGI:3057013

ht4

• Allelic Composition: Crebbp^tm1.1Ltz/Crebbp⁺
• Genetic Background: involves: 129P2/OlaHsd * C57BL/6N * CD-1

mortality/aging

premature death ( J:93192 )

• reduced survival is seen and this allele could not be backcrossed into C57BL/6N, however backcrossing into CD-1 produces viable offspring

Genotype
MGI:2175794

ht5

• Allelic Composition: Crebbp^tm1Dli/Crebbp⁺
• Genetic Background: involves: 129S6/SvEvTac * C57BL/6

growth/size/body

decreased body weight ( J:191503 )

postnatal growth retardation ( J:60630 )

enlarged spleen ( J:60630 , J:191503 )

• severe splenomegaly in 73% of 12-18 month old mice but not in young mice (J:60630)

• spleen contains an excess of myeloid and erythroid cells (J:60630)

• mild but significant splenomegaly in 3-4 and 9-12 month old mutants (J:191503)

craniofacial

abnormal craniofacial morphology ( J:60630 )

• craniofacial abnormalities

neoplasm

increased hemolymphoid system tumor incidence ( J:60630 )

• hematologic neoplasia in animals 1 year or older, which include histiocytic sarcomas, a tumor of hematopoietic origin, and myelogenous and lymphocytic leukemias

increased leukemia incidence ( J:60630 )

• myelogenous and lymphocytic leukemias

increased histiocytic sarcoma incidence ( J:60630 )

hematopoietic system

enlarged spleen ( J:60630 , J:191503 )

• severe splenomegaly in 73% of 12-18 month old mice but not in young mice (J:60630)

• spleen contains an excess of myeloid and erythroid cells (J:60630)

• mild but significant splenomegaly in 3-4 and 9-12 month old mutants (J:191503)

abnormal definitive hematopoiesis ( J:60630 , J:191503 )

• abundance of all hematopoietic cells types is significantly diminished in mice with splenomegaly (J:60630)

• increase in myeloid cells in mice with splenomegaly (J:60630)

• 2 of 14 mice at 3-4 months of age have small clusters of immature cells in the center of the marrow space, indicative of very early stages of myelodysplastic hematopoiesis (J:191503)

abnormal common myeloid progenitor cell morphology ( J:191503 )

• mutants show an increase in Annexin V+ cells in the lineage-depleted (Lin-) fraction of the marrow enriched for stem and progenitor cells, indicating an increase in apoptosis in marrow progenitors

decreased common myeloid progenitor cell number ( J:60630 , J:191503 )

• in mice with splenomegaly (J:60630)

• mutants have fewer total colony-forming cells in the marrow than wild-type mice, most notably the granulocytic and monocytic colony-forming cells (J:191503)

• 9-12 month old mutants show a decrease in common myeloid progenitors (J:191503)

extramedullary hematopoiesis ( J:60630 )

• in mice with splenomegaly

increased bone marrow cell number ( J:191503 )

• bone marrow is more cellular than in wild type mice when corrected for body weight at 3-4 and 9-12 months of age

abnormal megakaryocyte morphology ( J:191503 )

• more than 50% of 9-12 month old mutants exhibit either increased numbers of megakaryocytes or abnormal forms such as hyperlobulated cells or naked nuclei

increased megakaryocyte cell number ( J:191503 )

decreased hematopoietic stem cell number ( J:191503 )

• approximate 2-fold fewer long-term hematopoietic stem cells per femur at 9-12 months of age

abnormal leukocyte morphology ( J:191503 )

• 22% of 9-12 month old mutants show leukocytes with a pseudo Pelger-Huet anomaly

abnormal granulocyte morphology ( J:191503 )

• 55% of 9-12 month old mutants show hypersegemented granulocytes

increased granulocyte number ( J:191503 )

• at 9-12 months of age

decreased lymphocyte cell number ( J:191503 )

• lymphoid cell compartment is smaller at 9-12 months of age

• however, leukocyte, erythrocyte and platelet numbers are normal

decreased B cell number ( J:60630 )

• in mice with splenomegaly

absent pre-B cells ( J:60630 )

• in mice with splenomegaly

immune system

enlarged spleen ( J:60630 , J:191503 )

• severe splenomegaly in 73% of 12-18 month old mice but not in young mice (J:60630)

• spleen contains an excess of myeloid and erythroid cells (J:60630)

• mild but significant splenomegaly in 3-4 and 9-12 month old mutants (J:191503)

abnormal leukocyte morphology ( J:191503 )

• 22% of 9-12 month old mutants show leukocytes with a pseudo Pelger-Huet anomaly

abnormal granulocyte morphology ( J:191503 )

• 55% of 9-12 month old mutants show hypersegemented granulocytes

increased granulocyte number ( J:191503 )

• at 9-12 months of age

decreased lymphocyte cell number ( J:191503 )

• lymphoid cell compartment is smaller at 9-12 months of age

• however, leukocyte, erythrocyte and platelet numbers are normal

decreased B cell number ( J:60630 )

• in mice with splenomegaly

absent pre-B cells ( J:60630 )

• in mice with splenomegaly

cellular

increased cellular sensitivity to gamma-irradiation ( J:191503 )

• mutants treated with a 10-Gy split-dose total body irradiation die before wild-type mice do and none survive compared to 1/3 of wild-type mice that survive, indicating increased hypersensitivity to ionizing radiation

• a lower percentage of mutants treated with a split-dose of 11 Gy total body irradiation followed by a bone marrow graft survive compared to wild-type mice treated in the same way

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
acute myeloid leukemia		DOID:9119	OMIM:601626	J:60630
myelodysplastic syndrome		DOID:0050908	OMIM:614286	J:191503
Rubinstein-Taybi syndrome		DOID:1933	OMIM:180849 OMIM:610543 OMIM:613684	J:60630

Genotype
MGI:3588514

ht6

• Allelic Composition: Crebbp^tm1Sis/Crebbp⁺
• Genetic Background: involves: BALB/cCrSlc * C57BL/6NCrlj * CBA/JNCrlj

cardiovascular system

cardiovascular system phenotype ( J:42932 , J:63763 )

• heterozygotes do not exhibit any of the cardiac anomalies observed in Rubinstein-Taybi Syndrome (J:42932)

• heterozygotes do not exhibit any of the cardiac anomalies observed in Rubinstein-Taybi Syndrome (J:63763)

mortality/aging

prenatal lethality, incomplete penetrance ( J:42932 , J:63763 )

• a small subset of heterozygotes are embryonic lethal (J:42932)

• at 4 weeks of age, the ratio of wild-type:heterozygous genotypes is 1:1.2 (J:42932)

• a small subset of heterozygotes are embryonic lethal (J:63763)

• at 4 weeks of age, the ratio of wild-type:heterozygous genotypes is 1:1.2 (J:63763)

craniofacial

large anterior fontanelle ( J:42932 )

• Background Sensitivity: seen in 66% of heterozygotes on the mixed BALB/c, C57BL/6 and CBA background and in 25% of heterozygotes on a mixed C57BL/6 and CBA background

growth/size/body

postnatal growth retardation ( J:42932 )

• Background Sensitivity: 1/3 of heterozygotes exhibit growth retardation in the mixed BALB/c, C57BL/6, and CBA background while growth retardation is milder on the mixed C57BL/6 and CBA background

limbs/digits/tail

abnormal limb morphology ( J:42932 )

• low penetrance of limb abnormalities, however did not observe broad thumbs or broad halluces

skeleton

abnormal sternum morphology ( J:42932 )

• Background Sensitivity: 1/3 of heterozygotes exhibit various sternum abnormalities (extra, fusion, reduction, and asymmetry of the ossification with split in the sternum) on a mixed BALB/c, C57BL/6 and CBA background, while penetrance is significantly lower on the mixed C57BL/6 and CBA background

xiphoid process foramen ( J:42932 )

• Background Sensitivity: 29% of heterozygotes on the mixed BALB/c, C57BL/6, and CBA background exhibit distinct holes and fissures in the xiphoid process while 66% of heterozygotes on the mixed C57BL/6 and CBA background display xiphoid defects

abnormal rib morphology ( J:42932 )

• low frequency of rib abnormalities

scoliosis ( J:42932 )

• incomplete penetrance on the mixed BALB/c, C57BL/6, and CBA background

abnormal vertebrae morphology ( J:42932 )

• asymmetric cervical vertebrae, extra and split thoracic vertebrae, and scoliosis are observed on the mixed BALB/c, C57BL/6, and CBA background

abnormal joint morphology ( J:42932 )

• 1/3 of heterozygotes on a mixed BALB/c, C57BL/6 and CBA background have asymmetric sternocostal joints

large anterior fontanelle ( J:42932 )

• Background Sensitivity: seen in 66% of heterozygotes on the mixed BALB/c, C57BL/6 and CBA background and in 25% of heterozygotes on a mixed C57BL/6 and CBA background

delayed bone ossification ( J:42932 )

• delayed ossification of frontal bones on a mixed BALB/c, C57BL/6 and CBA background

Genotype
MGI:2175792

ht7

• Allelic Composition: Crebbp^{Gt(U-San)112Imeg}/Crebbp⁺
• Genetic Background: involves: C57BL/6 * CBA

mortality/aging

postnatal lethality ( J:53370 )

• a subset of F2 heterozygous pups die within several days after birth

growth/size/body

nasal bone hypoplasia ( J:53370 )

broad nasal bridge ( J:53370 )

short snout ( J:53370 )

decreased body weight ( J:75361 )

• at 2-14 weeks, heterozygotes show a 30% reduction in body weight relative to wild-type mice

• however, heterozygotes gain weight at a rate that is comparable to that observed in wild-type mice

decreased susceptibility to diet-induced obesity ( J:75361 )

• in contrast to wild-type mice, heterozygotes fail to show a time-dependent increase in weight on a high-fat (HF) diet

• heterozygotes appear to be protected against HF diet-induced triglyceride accumulation in WAT

abnormal embryonic growth/weight/body size ( J:53370 )

• heterozygotes exhibit significant intrauterine growth retardation in both weight and height relative to wild-type embryos

craniofacial

large anterior fontanelle ( J:53370 )

• at 19 dpc, heterozygotes exhibit a large anterior fontanel

wide frontal bone ( J:53370 )

• heterozygotes display widening of the frontal bone

short premaxilla ( J:53370 )

maxilla hypoplasia ( J:53370 )

short maxilla ( J:53370 )

nasal bone hypoplasia ( J:53370 )

broad nasal bridge ( J:53370 )

short snout ( J:53370 )

skeleton

large anterior fontanelle ( J:53370 )

• at 19 dpc, heterozygotes exhibit a large anterior fontanel

wide frontal bone ( J:53370 )

• heterozygotes display widening of the frontal bone

short premaxilla ( J:53370 )

maxilla hypoplasia ( J:53370 )

short maxilla ( J:53370 )

nasal bone hypoplasia ( J:53370 )

scoliosis ( J:53370 )

• 1 of 30 heterozygotes display severe scoliosis

delayed bone ossification ( J:53370 )

• heterozygotes exhibit delayed osseous maturation; notably, neither broad thumbs nor broad halluces are observed

cardiovascular system

abnormal heart morphology ( J:53370 )

• at 19.5 dpc, 9 of 54 heterozygous fetuses (16.6%) display non-overlapping cardiac abnormalities

atrial septal defect ( J:53370 )

• at 19.5 dpc, 1 of 54 heterozygous fetuses exhibit an atrial septal defect

perimembraneous ventricular septal defect ( J:53370 )

• at 19.5 dpc, 7 of 54 heterozygous fetuses exhibit a ventricular septal defect of the membranous type

behavior/neurological

impaired long-term object recognition memory ( J:53370 )

• heterozygotes display impaired long-term memory (LTM) in a step-through-type passive avoidance test and a cued fear-conditioning test

• in contrast, heterozygotes exhibit normal short-term memory in a Y-maze test as well as normal spatial learning in a water maze test

decreased vertical activity ( J:53370 )

• hypolocomotion in a dark environment is noted throughout the entire 60 min observation period in the vertical activity, but only in the first 5 min in the horizontal activity

decreased locomotor activity ( J:53370 )

• heterozygotes display hypolocomotion in a dark environment but not in a light environment

seizures ( J:53370 )

• at least 2 of 54 heterozygotes display seizures

nervous system

nervous system phenotype ( J:53370 )

N • heterozygotes exhibit a normal brain morphology: despite the LTM deficit, neither sensorimotor nor gross neuroanatomical anomalies are observed

seizures ( J:53370 )

• at least 2 of 54 heterozygotes display seizures

limbs/digits/tail

oligodactyly ( J:53370 )

• 1 of 30 heterozygotes exhibit oligodactyly

adipose tissue

decreased white adipose tissue amount ( J:75361 )

• at 8 months, heterozygotes show a significant reduction in WAT weight per body weight; the weight of other tissues, including brown adipose tissue, remains unchanged

• reduced WAT mass is attributed to the inhibition of triglyceride accumulation in WAT

decreased fat cell size ( J:75361 )

• at 8 months, heterozygotes fed a HC diet show a marked reduction in adipocyte size relative to similarly fed wild-type mice

decreased percent body fat/body weight ( J:75361 )

• at death, heterozygotes fed a high-carbohydrate (HC) diet display a significantly reduced fat mass relative to similarly fed wild-type mice

• however, at P3, heterozygotes contain the same amount of BAT and WAT as wild-type mice

cellular

abnormal cell differentiation ( J:75361 )

• in vitro, embryonic fibroblasts from heterozygous mice exhibit a reduced ability to differentiate into adipocytes upon induction with conventional hormonal stimuli

homeostasis/metabolism

decreased susceptibility to diet-induced obesity ( J:75361 )

• in contrast to wild-type mice, heterozygotes fail to show a time-dependent increase in weight on a high-fat (HF) diet

• heterozygotes appear to be protected against HF diet-induced triglyceride accumulation in WAT

increased circulating insulin level ( J:75361 )

• heterozygotes show higher plasma insulin levels during glucose tolerance tests suggesting increased insulin secretion; however, this rise in insulin levels does not reach statistical significance

increased circulating leptin level ( J:75361 )

• heterozygotes fed a HF diet display increased serum leptin levels relative to the severely reduced WAT mass

decreased circulating free fatty acids level ( J:75361 )

• heterozygotes fed a HF diet display reduced serum levels of free fatty acids relative to wild-type mice

increased oxygen consumption ( J:75361 )

• heterozygotes exhibit a marked increase in resting oxygen consumption relative to wild-type mice

• in contrast, food intake remains relatively unchanged on either the HC or HF diet

improved glucose tolerance ( J:75361 )

• heterozygotes display increased glucose tolerance relative to wild-type mice on both a HC and a HF diet

increased insulin sensitivity ( J:75361 )

• despite lipodystrophy, heterozygotes exhibit an enhanced glucose-lowering insulin effect relative to wild-type mice

increased circulating adiponectin level ( J:75361 )

• heterozygotes fed a HF diet show a significant increase in serum adiponectin levels, despite their markedly reduced WAT mass

decreased triglyceride level ( J:75361 )

• heterozygotes display changes in gene expression associated with decreased tissue triglyceride content in skeletal muscle and liver

abnormal tumor necrosis factor level ( J:75361 )

• heterozygotes fed a HF diet display reduced Tnfa mRNA levels in WAT relative to wild-type mice

increased response to leptin ( J:75361 )

• heterozygotes fed a HF diet exhibit increased leptin sensitivity in response to exogenous leptin

immune system

abnormal tumor necrosis factor level ( J:75361 )

• heterozygotes fed a HF diet display reduced Tnfa mRNA levels in WAT relative to wild-type mice

respiratory system

nasal bone hypoplasia ( J:53370 )

broad nasal bridge ( J:53370 )

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
Rubinstein-Taybi syndrome		DOID:1933	OMIM:180849 OMIM:610543 OMIM:613684	J:53370

Genotype
MGI:2175796

ht8

• Allelic Composition: Crebbp^tm1Sis/Crebbp⁺
• Genetic Background: involves: C57BL/6NCrlj * CBA/JNCrlj

Skeletal formation defects in Crebbp^tm1Sis/Crebbp⁺ mice

growth/size/body

postnatal growth retardation ( J:42932 )

• Background Sensitivity: growth retardation is milder than in mice on a background containing BALB/c

skeleton

large anterior fontanelle ( J:42932 )

• Background Sensitivity: in 25% of mice compared to in 66% of heterozygotes on a background containing BALB/c

abnormal sternum morphology ( J:42932 )

• Background Sensitivity: at a much lower than in mice on a background containing BALB/c

xiphoid process foramen ( J:42932 )

• Background Sensitivity: in 16 of 24 mice, more frequent than in mice on a background containing BALB/c

craniofacial

large anterior fontanelle ( J:42932 )

• Background Sensitivity: in 25% of mice compared to in 66% of heterozygotes on a background containing BALB/c

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
Rubinstein-Taybi syndrome		DOID:1933	OMIM:180849 OMIM:610543 OMIM:613684	J:42932

Genotype
MGI:3046632

ht9

• Allelic Composition: Crebbp^tm1Few/Crebbp⁺
• Genetic Background: Not Specified

endocrine/exocrine glands

abnormal pancreatic beta cell morphology ( J:91133 )

homeostasis/metabolism

abnormal glucose homeostasis ( J:91133 )

• fasting mutants show an enhanced response to glucagon indicating increased gluconeogenesis

increased circulating glucose level ( J:91133 )

• increased fasting and fed blood glucose levels are seen

• hepatic glucose output is increased

decreased circulating glucagon level ( J:91133 )

• lower basal serum glucagon levels are seen

increased circulating insulin level ( J:91133 )

• serum insulin is increased in intraperitoneal glucose tolerance tests and in fed mutants compared to wild-type mice

impaired glucose tolerance ( J:91133 )

• mutants display glucose intolerance associated with increased serum insulin

increased liver glycogen level ( J:91133 )

• liver glycogen levels are not decreased after fasting

insulin resistance ( J:91133 )

• fasting mutants show insulin resistance compared to wild-type mice

liver/biliary system

increased liver glycogen level ( J:91133 )

• liver glycogen levels are not decreased after fasting

Genotype
MGI:3626197

cx10

• Allelic Composition: Crebbp^tm2Pkb/Crebbp⁺; Ep300^tm3Pkb/Ep300⁺
• Genetic Background: involves: 129P2/OlaHsd * 129S6/SvEvTac * C57BL/6

growth/size/body

decreased body size ( J:103607 )

• compound mutants are smaller than littermates

craniofacial

abnormal craniofacial morphology ( J:103607 )

• some compound heterozygotes have craniofacial defects

Genotype
MGI:3626199

cx11

• Allelic Composition: Crebbp^tm2Pkb/Crebbp⁺; Ep300^tm3Pkb/Ep300^tm3Pkb
• Genetic Background: involves: 129P2/OlaHsd * 129S6/SvEvTac * C57BL/6

mortality/aging

embryonic lethality during organogenesis, incomplete penetrance ( J:103607 )

• viable embryos can be recovered at E14.5

Genotype
MGI:3626200

cx12

• Allelic Composition: Crebbp^tm2Pkb/Crebbp⁺; Tg(IghMyc)22Bri/0
• Genetic Background: involves: 129P2/OlaHsd * C57BL/6 * SJL

neoplasm

abnormal tumor incidence ( J:103607 )

• on a hybrid background presence of a single Crebb^tm2Pkb allele decreased the median survival time by about 8-10 weeks compared to wild-type transgenic littermates

Genotype
MGI:3512279

cx13

• Allelic Composition: Crebbp^tm1Dli/Crebbp⁺; Ep300^tm1Dli/Ep300⁺
• Genetic Background: involves: 129S4/SvJae * 129S6/SvEvTac * C57BL/6

mortality/aging

prenatal lethality, complete penetrance ( J:47301 )

• unexpectedly, compound heterozygotes die in utero

embryo

decreased embryo size ( J:47301 )

• compound heterozygotes are smaller than control embryos

open neural tube ( J:47301 )

• compound heterozygotes exhibit a severe open neural tube defect similar to that observed in Ep300^tm1Dli or Crebbp^tm1Dli homozygous mutants

growth/size/body

decreased embryo size ( J:47301 )

• compound heterozygotes are smaller than control embryos

nervous system

open neural tube ( J:47301 )

• compound heterozygotes exhibit a severe open neural tube defect similar to that observed in Ep300^tm1Dli or Crebbp^tm1Dli homozygous mutants

exencephaly ( J:47301 )

• compound heterozygotes exhibit extensive exencephaly