Autosomal Recessive Primary Microcephaly
Autosomal recessive primary microcephaly (MCPH) is a genetically heterogeneous group of prenatal brain-growth disorders characterized by primary microcephaly and usually intellectual or developmental impairment. The classic phenotype has a small cerebral cortex with simplified gyration and few major extracranial anomalies, but individual genetic subtypes can include cortical malformations, spasticity, epilepsy, ataxia, short stature, or other syndromic features. Biallelic variants disrupt multiple processes needed to expand the fetal neural-progenitor pool, including centrosome and spindle organization, chromosome segregation and DNA repair, cytokinesis, membrane trafficking, lipid transport, ribosome biogenesis, and ciliary dynamics. These lesions converge variably on mitotic delay, DNA damage, TP53-linked apoptosis, premature differentiation, and reduced cortical-neuron output.
Ask OpenScientist
Ask a research question about Autosomal Recessive Primary Microcephaly. OpenScientist will conduct autonomous deep research using the Disorder Mechanisms Knowledge Base and PubMed literature (typically 10-30 minutes).
Submitting...
Do not include personal health information in your question. Questions and results are cached in your browser's local storage.
Mappings
MONDO
MONDO:0016660
autosomal recessive primary microcephaly
Inheritance
1
Autosomal recessive inheritance
HP:0000007
The numbered MCPH entities in this entry are caused by biallelic pathogenic variants. For a couple who are both heterozygous for the same disease-causing gene, each pregnancy has a 25% affected recurrence risk.
Show evidence (2 references)
"ASPM-MCPH is inherited in an autosomal recessive manner."
GeneReviews explicitly states autosomal recessive inheritance for the most common MCPH subtype.
"WDR62-MCPH is inherited in an autosomal recessive manner."
GeneReviews independently confirms recessive inheritance for MCPH2.
Subtypes
28
MCPH1 (MCPH1)
MONDO:0009617
Biallelic MCPH1 variants cause the MCPH1 subtype.
Show evidence (1 reference)
"MCPH1 Microcephalin 1 MCPH1 8p23.1 607117"
The review's MCPH table maps the MCPH1 locus to MCPH1.
MCPH2 (WDR62)
MONDO:0011435
Biallelic WDR62 variants cause MCPH2, often with additional cortical malformations.
Show evidence (1 reference)
"The diagnosis of WDR62-MCPH is established in a proband with suggestive clinical findings and biallelic pathogenic variants in WDR62 identified by molecular genetic testing."
GeneReviews establishes the biallelic WDR62 basis of MCPH2.
MCPH3 (CDK5RAP2)
MONDO:0011488
Biallelic CDK5RAP2 variants cause the MCPH3 subtype.
Show evidence (1 reference)
"MCPH3 Cyclin-dependent kinase 5 regulatory subunit-associated protein 2 CDK5RAP2 9q33.2 608201"
The review's MCPH table maps MCPH3 to CDK5RAP2.
MCPH4 (KNL1)
MONDO:0011437
Biallelic KNL1 variants cause the MCPH4 subtype.
Show evidence (1 reference)
"MCPH4 Kinetochore scaffold 1 KNL1 15q15.1 609173"
The review's MCPH table maps MCPH4 to KNL1.
MCPH5 (ASPM)
MONDO:0012106
Biallelic ASPM variants cause MCPH5, the most common classic subtype.
Show evidence (1 reference)
"The diagnosis of ASPM-MCPH is established in a proband with biallelic pathogenic variants in ASPM identified by molecular genetic testing."
GeneReviews establishes the biallelic ASPM basis of MCPH5.
MCPH6 (CENPJ)
MONDO:0012029
Biallelic CENPJ variants cause the MCPH6 subtype.
Show evidence (1 reference)
"MCPH6 Centromeric protein J CENPJ 13q12.2 609279"
The review's MCPH table maps MCPH6 to CENPJ.
MCPH7 (STIL)
MONDO:0012989
Biallelic STIL variants cause the MCPH7 subtype.
Show evidence (1 reference)
"MCPH7 SCL/TAL1- interrupting locus protein STIL 1p33 181590"
The review's MCPH table maps MCPH7 to STIL.
MCPH8 (CEP135)
MONDO:0013849
Biallelic CEP135 variants cause the MCPH8 subtype.
Show evidence (1 reference)
"MCPH8 Centrosomal protein 135 kD CEP135 4q12 611423"
The review's MCPH table maps MCPH8 to CEP135.
MCPH9 (CEP152)
MONDO:0013923
Biallelic CEP152 variants cause the MCPH9 subtype.
Show evidence (1 reference)
"MCPH9 Centrosomal protein 152 kD CEP152 15q21.1 613529"
The review's MCPH table maps MCPH9 to CEP152.
MCPH10 (ZNF335)
MONDO:0014043
Biallelic ZNF335 variants cause the current MONDO child named microcephalic primordial dwarfism due to ZNF335 deficiency.
Show evidence (1 reference)
"ZNF335; MCPH10"
The review's MCPH table maps MCPH10 to ZNF335.
MCPH11 (PHC1)
MONDO:0014173
Biallelic PHC1 variants cause the MCPH11 subtype.
Show evidence (1 reference)
"MCPH11 Polyhomeotic-like 1 protein PHC1 12p13.31 602978"
The review's MCPH table maps MCPH11 to PHC1.
MCPH12 (CDK6)
MONDO:0014484
Biallelic CDK6 variants cause the MCPH12 subtype.
Show evidence (1 reference)
"MCPH12 Cyclin-dependent kinase 6 CDK6 7q21.2 603368"
The review's MCPH table maps MCPH12 to CDK6.
MCPH13 (CENPE)
MONDO:0014473
Biallelic CENPE variants cause the MCPH13 subtype.
Show evidence (1 reference)
"MCPH13 Centromeric protein E CENPE 4q24 117143"
The review's MCPH table maps MCPH13 to CENPE.
MCPH14 (SASS6)
MONDO:0014623
Biallelic SASS6 variants cause the MCPH14 subtype.
Show evidence (1 reference)
"MCPH14 SAS-6 centriolar assembly protein SASS6 1p21.2 609321"
The review's MCPH table maps MCPH14 to SASS6.
MCPH15 (MFSD2A)
MONDO:0014660
Biallelic MFSD2A variants cause the MCPH15 subtype.
Show evidence (1 reference)
"MCPH15 Major facilitator superfamily domain- containing protein 2A MFSD2A 1p34.2 614397"
The review's MCPH table maps MCPH15 to MFSD2A.
MCPH16 (ANKLE2)
MONDO:0014730
Biallelic ANKLE2 variants cause the MCPH16 subtype.
Show evidence (1 reference)
"MCPH16 ANKLE2 12q24.33 616062"
The review's MCPH table maps MCPH16 to ANKLE2.
MCPH17 (CIT)
MONDO:0014908
Biallelic CIT variants cause MCPH17 through cytokinesis dysfunction.
Show evidence (1 reference)
"Biallelic citron rho-interacting serine/threonine kinase (CIT) missense variants that disrupt kinase function (CITKI/KI) and frameshift loss-of-function variants (CITFS/FS) are the genetic basis for MCPH17"
Human genetic and functional work directly establishes CIT as the MCPH17 gene.
MCPH19 (COPB2)
MONDO:0054716
Biallelic COPB2 variants cause the MCPH19 subtype.
Show evidence (1 reference)
"MCPH19 Coatomer protein complex, subunit beta 2 (beta prime) COPB2 3q23 606990"
The review's MCPH table maps MCPH19 to COPB2.
MCPH20 (KIF14)
MONDO:0054761
Biallelic KIF14 variants cause the MCPH20 subtype.
Show evidence (1 reference)
"MCPH20 Kinesin family member 14 KIF14 1q32.1 611279"
The review's MCPH table maps MCPH20 to KIF14.
MCPH21 (NCAPD2)
MONDO:0054804
Biallelic NCAPD2 variants cause the MCPH21 subtype.
Show evidence (1 reference)
"MCPH21 Non-SMC condensin I complex, subunit D2 NCAPD2 12p13.31 615638"
The review's MCPH table maps MCPH21 to NCAPD2.
MCPH22 (NCAPD3)
MONDO:0054805
Biallelic NCAPD3 variants cause the MCPH22 subtype.
Show evidence (1 reference)
"MCPH22 Non-SMC condensin II complex subunit D3 NCAPD3 11q25 609276"
The review's MCPH table maps MCPH22 to NCAPD3.
MCPH23 (NCAPH)
MONDO:0054806
Biallelic NCAPH variants cause the MCPH23 subtype.
Show evidence (1 reference)
"MCPH23 Non-SMC condensin I complex subunit H NCAPH 2q11.2 602332"
The review's MCPH table maps MCPH23 to NCAPH.
MCPH24 (NUP37)
MONDO:0032583
Biallelic NUP37 variants cause the MCPH24 subtype.
Show evidence (1 reference)
"MCPH24 Nucleoporin 37 NUP37 12q23.2 609264"
The review's MCPH table maps MCPH24 to NUP37.
MCPH25 (TRAPPC14)
MONDO:0032694
Biallelic TRAPPC14 variants cause the MCPH25 subtype.
Show evidence (1 reference)
"TRAPPC14 mutations have been linked to MCPH25 in human"
The review's MCPH table maps MCPH25 to TRAPPC14.
MCPH28 (RRP7A)
MONDO:0030339
Biallelic RRP7A variants cause MCPH28 through ribosome, cilium, and cell-cycle dysfunction.
Show evidence (1 reference)
"We identified a homozygous missense mutation (p.W155C) in Ribosomal RNA Processing 7 Homolog A, RRP7A, segregating with MCPH in a consanguineous family with 10 affected individuals."
The discovery study establishes recessive RRP7A-associated MCPH.
MCPH29 (PDCD6IP)
MONDO:0031060
Biallelic PDCD6IP variants cause the current MCPH29 subtype.
Show evidence (1 reference)
"We report a consanguineous family with PM, intellectual disability and short stature. Using whole exome sequencing, we identified a homozygous frameshift variant in programmed cell death 6 interacting protein"
The discovery family supports biallelic PDCD6IP as a primary-microcephaly cause.
MCPH30 (BUB1)
MONDO:0859342
Biallelic BUB1 variants cause the current MCPH30 subtype; the discovery paper emphasized overlap with MCPH, aneuploidy syndromes, and cohesinopathies.
Show evidence (1 reference)
"Here, we describe the first two patients with biallelic BUB1 germline mutations, who both display microcephaly, intellectual disability, and several patient-specific features."
The discovery report establishes the recessive BUB1 neurodevelopmental phenotype.
MCPH31 (CETN3)
MONDO:0980991
Biallelic loss-of-function CETN3 variants cause the current MCPH31 subtype.
Show evidence (1 reference)
"Through whole-exome sequencing, we identified compound heterozygous loss-of-function mutations in CENTRIN 3 (CETN3) in a 5-year-old patient with primary microcephaly."
The discovery and functional study establishes biallelic CETN3-associated primary microcephaly.
Discussions and Knowledge Gaps
3Which MCPH mechanisms require gyrencephalic or human neural models because lissencephalic rodents under-reproduce the relevant progenitor biology?
Attached to
CIT kinase-dead mice fail to reproduce the human microcephaly phenotype, while human forebrain organoids reveal severe cytoarchitectural and cytokinesis-polarity defects. ASPM ferrets and human organoids also model outer-radial-glia biology that is sparse in mouse cortex. Cross-model agreement should therefore be evaluated mechanism by mechanism rather than treating a negative mouse phenotype as disproof.
Show evidence (1 reference)
"we created the CitKI/KI mouse model and found that it did not phenocopy human microcephaly, unlike biallelic CitFS/FS animals."
The CIT allelic models provide direct evidence of a human–mouse phenotype mismatch.
Can apoptosis be modulated safely enough to preserve neural progenitors without allowing genomically damaged cells to persist?
TP53-linked apoptosis is a convergence point across many MCPH models and is pharmacologically tractable in principle, but it also protects developing tissue from cells with segregation, cytokinesis, or DNA-repair defects. Rescue of size alone is therefore not an adequate safety or efficacy endpoint.
Show evidence (1 reference)
"In consideration of the potential druggability of cell apoptotic pathways, a better understanding of their role in MCPH may significantly facilitate the development of translational approaches."
The review explicitly identifies apoptosis as a potentially druggable but unresolved translational target.
How should future MCPH loci be incorporated while preserving the boundary between classic isolated MCPH, syndromic microcephaly, primordial dwarfism, and broader cortical-malformation disorders?
The numbered series is actively evolving: a 2021 review listed MCPH1-28, a 2023 mechanism review referred to MCPH1-30, and CETN3-associated disease was reported in 2025 and is now represented as MCPH31 in MONDO. Historical numbering alone cannot determine current ontology ancestry or whether a phenotype should be lumped into this umbrella.
Show evidence (2 references)
"twenty-eight MCPH-related genes"
The review supplies a dated snapshot that demonstrates evolution of the locus series.
"As CETN3 has not been previously linked to microcephaly"
The CETN3 discovery illustrates continuing expansion beyond earlier numbered snapshots.
Pathophysiology
9Heterogeneous Biallelic MCPH Gene Dysfunction
Biallelic pathogenic variants in the current MONDO MCPH subtype genes perturb several cellular systems that are essential for fetal neural-progenitor expansion. The locus set is mechanistically heterogeneous, so centrosome dysfunction is an important convergence point rather than a complete explanation for every subtype.
Downstream
Many MCPH proteins directly build or regulate centrioles, centrosomes, spindle poles, microtubules, and kinetochores.
MCPH1, PHC1, ZNF335, condensin-subunit, and related defects disrupt genome organization or surveillance.
CIT, KIF14, PDCD6IP, COPB2, and TRAPPC14 perturb cytokinesis or membrane-trafficking machinery.
RRP7A and MFSD2A illustrate noncanonical routes into impaired brain growth.
Show evidence (2 references)
"Most are caused by biallelic or, more rarely, dominant mutations in one of the likely hundreds of genes encoding PM proteins"
The contemporary review establishes the genetically heterogeneous, usually biallelic basis of primary microcephalies.
"MCPH proteins play crucial roles in microtubule dynamics, mitotic spindle formation, DNA damage responses, Wnt signaling, transcriptional regulation, and cell cycle checkpoint control"
The review documents mechanistic heterogeneity across the MCPH locus series.
Centrosome, Spindle, and Kinetochore Dysfunction
Defective centriole assembly, centrosome maturation, spindle-pole organization, kinetochore function, or spindle orientation delays mitosis and increases chromosome-segregation errors in dividing neural progenitors. Individual genes affect different structures, so this node is a mechanistic family rather than a claim of identical molecular lesions.
Experimental models
WDR62 patient-derived neural progenitor and cerebral organoid models
The system measures WDR62 localization and mitotic progression in human neural progenitors.
CETN3-knockout human cerebral organoids
The organoids test how CETN3 loss impairs centrosome assembly and progenitor cell-cycle progression.
Downstream
Mitotic errors produce DNA damage, checkpoint stress, and apoptotic loss in susceptible neural progenitors.
WDR62 dysfunction can affect cortical organization in addition to brain size.
Show evidence (2 references)
"WDR62 dysfunction impairs mitotic progression and results in alterations of the neurogenic trajectories of iPSC neuroderivatives."
Human neural models directly connect WDR62 dysfunction to mitotic and neurogenic defects.
"Both patients’ cells show prolonged mitosis duration, chromosome segregation errors, and an overall functional spindle assembly checkpoint."
Patient cells demonstrate a kinetochore-associated route to mitotic delay and segregation errors.
Chromatin, DNA Repair, and Condensin Dysfunction
MCPH1-associated premature chromosome condensation and DNA-repair failure, PHC1/ZNF335-associated chromatin regulation, and condensin-subunit defects compromise chromosome architecture and segregation. The resulting genome stress is particularly costly during rapid fetal neural-progenitor expansion.
Downstream
Genome-architecture failure activates checkpoints and apoptotic surveillance.
Show evidence (1 reference)
"premature chromosome condensation (PCC) associated with a high frequency of prophase-like cells and defective DNA damage repair"
Patient cells and models establish the canonical MCPH1 chromosome-condensation and repair phenotype.
Cytokinesis and Membrane-Trafficking Dysfunction
CIT and KIF14 participate in cytokinesis, PDCD6IP supports ESCRT-mediated abscission, and COPB2/TRAPPC14 support trafficking and spindle-associated processes. Failure of daughter-cell separation produces binucleation, genomic instability, arrest, or apoptosis.
Experimental models
CIT kinase-dead and frameshift human forebrain organoids
The organoids resolve CIT catalytic and scaffolding requirements during neural-progenitor cytokinesis.
Downstream
Cytokinesis failure produces binucleated cells, DNA damage, and apoptosis.
Show evidence (2 references)
"both CIT catalytic and scaffolding functions in NPC cytokinesis are critical for human corticogenesis."
Human forebrain organoids directly establish CIT-dependent neural-progenitor cytokinesis.
"PDCD6IP, plays an important role in the endosomal sorting complexes required for transport (ESCRT) pathway in the abscission stage of cytokinesis and apoptosis"
The discovery paper establishes the ESCRT/abscission mechanism for PDCD6IP-associated disease.
Ribosome, Cilium, and Lipid-Transport Dysfunction
Not every MCPH subtype begins with a spindle lesion. RRP7A deficiency impairs ribosomal RNA processing, cilium resorption, and cell-cycle progression; MFSD2A deficiency limits transport of essential lysophospholipid-bound fatty acids across the blood-brain barrier. These routes still reduce neural proliferation or survival.
Downstream
Ribosome/cilium dysfunction or insufficient brain lipid delivery reduces progenitor output and neuronal survival.
Show evidence (2 references)
"RRP7A localizes to centrosomes, cilia and nucleoli, and patient-derived fibroblasts display defects in ribosomal RNA processing, primary cilia resorption, and cell cycle progression."
Patient-derived cells establish a noncanonical RRP7A mechanism.
"MFSD2A (MCPH15) gene"
The review identifies the distinct MFSD2A lipid-transport mechanism.
Mitotic Stress, DNA Damage, and TP53-Linked Apoptosis
Prolonged or failed mitosis, chromosome bridges, cytokinesis failure, and repair defects generate genome stress. Across many MCPH models this activates TP53-linked apoptosis, eliminating progenitors and sometimes postmitotic neurons. TP53 activation is a convergence mechanism, not yet a proven safe therapeutic target.
Downstream
Apoptotic loss and cell-cycle arrest reduce the number of progenitors available for cortical neurogenesis.
Show evidence (1 reference)
"the molecular and cellular events produced by mutation of the majority of MCPH genes may converge on apoptotic death of NPCs and neurons, via TP53 activation."
The review synthesizes TP53-linked apoptosis as a cross-locus convergence mechanism.
Neural-Progenitor Proliferation and Survival Failure
Mitotic delay, apoptosis, and a premature shift from self-renewing to neurogenic divisions deplete apical and basal radial-glial progenitors during the period when the fetal cortex normally amplifies its founder pool.
Experimental models
WDR62 patient-derived neural progenitor and cerebral organoid models
Cerebral organoids model altered division choice and premature neurogenesis.
CDK5RAP2 patient-derived high-quantity brain organoids
The platform models the patient-specific developmental defect at reproducible scale.
Downstream
A smaller progenitor pool produces fewer cortical neurons and less tangential cortical expansion.
Show evidence (2 references)
"RG-like progenitors in Mut COs displayed asymmetric cell divisions more frequently, suggestive of premature differentiation"
Patient-derived cerebral organoids directly show a shift toward neurogenic divisions.
"CETN3 deficiency directly interferes with neuronal differentiation and reduces proliferative capacity in neural stem/progenitor cells"
CETN3 organoids independently support altered fate and reduced proliferation.
Reduced Cortical-Neuron Output and Simplified Gyration
Reduced neuron production limits fetal cerebral-cortex growth. The typical result is primary microcephaly with a reduced brain volume and simplified gyral pattern; cognitive and developmental consequences vary with the affected gene and with additional malformations.
Downstream
Reduced cortical growth produces the defining congenital small-head phenotype.
Reduced tangential cortical expansion produces fewer and shallower folds.
Reduced or malformed cortical circuitry contributes to variable intellectual disability.
The brain-growth disorder delays acquisition of developmental milestones.
Speech-language delay is a prominent functional consequence across genetic primary microcephaly cohorts.
Behavioral abnormalities occur in MCPH, but their circuit-level basis is unresolved.
Show evidence (1 reference)
"Most MCPH cases show a reduction in brain volume"
Neuroimaging synthesis establishes the core structural phenotype.
WDR62-Associated Cortical Malformation Branch
WDR62-related MCPH2 often extends beyond proportional cortical undergrowth. Altered neural-progenitor mitosis and neurogenic trajectories can coexist with pachygyria, heterotopia, schizencephaly, or microlissencephaly, increasing motor, epilepsy, and functional burden.
Downstream
Pachygyria is one of the recurrent WDR62-associated cortical malformations.
Epilepsy is a variable WDR62-MCPH manifestation.
Spasticity is a variable motor manifestation in WDR62-related disease.
Ataxia can occur and was progressive in one longitudinally observed patient.
Show evidence (1 reference)
"Brain malformations, including pachygyria, neuronal heterotopia, schizencephaly, and microlissencephaly, were present in 11 out of 15 patients."
Systematic imaging documents the subtype-specific malformation branch.
Pathograph
Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Phenotypes
10Musculoskeletal 1
Spasticity
HP:0001257
Human Phenotype Ontology (HP)
Relation: this clinical feature is this phenotype
This clinical feature is Spasticity (HP:0001257). HP:0001257 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
"Neurologic examination is usually normal except for mild spasticity."
ASPM GeneReviews directly documents mild spasticity.
Nervous System 6
Intellectual Disability
HP:0001249
Human Phenotype Ontology (HP)
Relation: this clinical feature is this phenotype
This clinical feature is Intellectual disability (HP:0001249). HP:0001249 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
"In the MCPH group, borderline to mild intellectual disability, independent of microcephaly severity"
A contemporary cohort documents intellectual impairment independent of head-size severity.
"Intellectual disability was severe in four patients, moderate in four, and mild in three."
The WDR62 cohort demonstrates the full severity range.
Global Developmental Delay
HP:0001263
Human Phenotype Ontology (HP)
Relation: this clinical feature is this phenotype
This clinical feature is Global developmental delay (HP:0001263). HP:0001263 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
"Central nervous system involvement can include delayed motor development"
WDR62 GeneReviews directly supports developmental delay within the MCPH spectrum.
Delayed Speech and Language Development
HP:0000750
Human Phenotype Ontology (HP)
Relation: this clinical feature is this phenotype
This clinical feature is Delayed speech and language development (HP:0000750). HP:0000750 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
"Most patients in both groups had speech delay."
The cohort identifies speech delay as a common functional feature.
Atypical Behavior
HP:0000708
Human Phenotype Ontology (HP)
Relation: this clinical feature is this phenotype
This clinical feature is Atypical behavior (HP:0000708). HP:0000708 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
"behavioral abnormalities were prominent"
The contemporary cohort directly documents behavioral abnormalities.
Seizure
HP:0001250
Human Phenotype Ontology (HP)
Relation: this clinical feature is this phenotype
This clinical feature is Seizure (HP:0001250). HP:0001250 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
"Central nervous system involvement can include delayed motor development, mild-to-severe intellectual disability (ID), behavior problems, epilepsy, spasticity, and ataxia."
GeneReviews includes epilepsy in the WDR62-MCPH clinical spectrum.
Ataxia
HP:0001251
Human Phenotype Ontology (HP)
Relation: this clinical feature is this phenotype
This clinical feature is Ataxia (HP:0001251). HP:0001251 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
"One patient displayed progressive ataxia."
The WDR62 cohort directly documents progressive ataxia.
Other 3
Primary Microcephaly
HP:0011451
Human Phenotype Ontology (HP)
Relation: this clinical feature is this phenotype
This clinical feature is Primary microcephaly (HP:0011451). HP:0011451 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
"usually present at birth and always present before age one year"
GeneReviews supplies the defining early head-circumference phenotype.
Simplified Gyral Pattern
HP:0009879
Human Phenotype Ontology (HP)
Relation: this clinical feature is this phenotype
This clinical feature is Simplified gyral pattern (HP:0009879). HP:0009879 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
"Most MCPH cases show a reduction in brain volume"
The review identifies simplified neocortical gyration as the typical imaging pattern.
Pachygyria
HP:0001302
Human Phenotype Ontology (HP)
Relation: this clinical feature is this phenotype
This clinical feature is Pachygyria (HP:0001302). HP:0001302 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
"Brain malformations, including pachygyria, neuronal heterotopia, schizencephaly, and microlissencephaly, were present in 11 out of 15 patients."
The WDR62 cohort directly documents pachygyria.
Genetic Associations
28
MCPH1
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"MCPH1 Microcephalin 1 MCPH1 8p23.1 607117"
The MCPH locus table maps MCPH1 to the MCPH1 gene.
WDR62
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"The diagnosis of WDR62-MCPH is established in a proband with suggestive clinical findings and biallelic pathogenic variants in WDR62 identified by molecular genetic testing."
GeneReviews establishes the biallelic WDR62 association.
CDK5RAP2
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"MCPH3 Cyclin-dependent kinase 5 regulatory subunit-associated protein 2 CDK5RAP2 9q33.2 608201"
The MCPH locus table maps MCPH3 to CDK5RAP2.
KNL1
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"MCPH4 Kinetochore scaffold 1 KNL1 15q15.1 609173"
The MCPH locus table maps MCPH4 to KNL1.
ASPM
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"The diagnosis of ASPM-MCPH is established in a proband with biallelic pathogenic variants in ASPM identified by molecular genetic testing."
GeneReviews establishes the biallelic ASPM association.
CENPJ
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"MCPH6 Centromeric protein J CENPJ 13q12.2 609279"
The MCPH locus table maps MCPH6 to CENPJ.
STIL
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"MCPH7 SCL/TAL1- interrupting locus protein STIL 1p33 181590"
The MCPH locus table maps MCPH7 to STIL.
CEP135
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"MCPH8 Centrosomal protein 135 kD CEP135 4q12 611423"
The MCPH locus table maps MCPH8 to CEP135.
CEP152
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"MCPH9 Centrosomal protein 152 kD CEP152 15q21.1 613529"
The MCPH locus table maps MCPH9 to CEP152.
ZNF335
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
PHC1
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"MCPH11 Polyhomeotic-like 1 protein PHC1 12p13.31 602978"
The MCPH locus table maps MCPH11 to PHC1.
CDK6
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"MCPH12 Cyclin-dependent kinase 6 CDK6 7q21.2 603368"
The MCPH locus table maps MCPH12 to CDK6.
CENPE
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"MCPH13 Centromeric protein E CENPE 4q24 117143"
The MCPH locus table maps MCPH13 to CENPE.
SASS6
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"MCPH14 SAS-6 centriolar assembly protein SASS6 1p21.2 609321"
The MCPH locus table maps MCPH14 to SASS6.
MFSD2A
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"MCPH15 Major facilitator superfamily domain- containing protein 2A MFSD2A 1p34.2 614397"
The MCPH locus table maps MCPH15 to MFSD2A.
ANKLE2
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"MCPH16 ANKLE2 12q24.33 616062"
The MCPH locus table maps MCPH16 to ANKLE2.
CIT
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"Biallelic citron rho-interacting serine/threonine kinase (CIT) missense variants that disrupt kinase function (CITKI/KI) and frameshift loss-of-function variants (CITFS/FS) are the genetic basis for MCPH17"
The study directly establishes biallelic CIT variants as the MCPH17 basis.
COPB2
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"mutations in COPB2 interrupt brain growth and lead to MCPH19"
The review directly links COPB2 variants to MCPH19.
KIF14
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"MCPH20 Kinesin family member 14 KIF14 1q32.1 611279"
The MCPH locus table maps MCPH20 to KIF14.
NCAPD2
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"Mutations in genes encoding condensin complex proteins NCAPD2, NCAPD3, and NCAPH have been linked to MCPH21, 22, and 23, respectively"
The review explicitly maps NCAPD2 to MCPH21.
NCAPD3
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"Mutations in genes encoding condensin complex proteins NCAPD2, NCAPD3, and NCAPH have been linked to MCPH21, 22, and 23, respectively"
The review explicitly maps NCAPD3 to MCPH22.
NCAPH
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"Mutations in genes encoding condensin complex proteins NCAPD2, NCAPD3, and NCAPH have been linked to MCPH21, 22, and 23, respectively"
The review explicitly maps NCAPH to MCPH23.
NUP37
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"MCPH24 Nucleoporin 37 NUP37 12q23.2 609264"
The MCPH locus table maps MCPH24 to NUP37.
TRAPPC14
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"TRAPPC14 mutations have been linked to MCPH25 in human"
The review directly links TRAPPC14 variants to MCPH25.
RRP7A
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"We identified a homozygous missense mutation (p.W155C) in Ribosomal RNA Processing 7 Homolog A, RRP7A, segregating with MCPH in a consanguineous family with 10 affected individuals."
The discovery family establishes recessive RRP7A-associated MCPH.
PDCD6IP
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"we identified a homozygous frameshift variant in programmed cell death 6 interacting protein (PDCD6IP, c.154_158dup; p.Val54Profs*18)."
The discovery family establishes a biallelic PDCD6IP association.
BUB1
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"Here, we describe the first two patients with biallelic BUB1 germline mutations, who both display microcephaly, intellectual disability, and several patient-specific features."
The discovery report establishes biallelic BUB1-associated microcephaly.
CETN3
(Biallelic Pathogenic Variant)
Show evidence (1 reference)
"Through whole-exome sequencing, we identified compound heterozygous loss-of-function mutations in CENTRIN 3 (CETN3) in a 5-year-old patient with primary microcephaly."
The discovery study establishes biallelic CETN3-associated primary microcephaly.
External Assertions
4ClinGen ASPM–autosomal recessive primary microcephaly validity
The ClinGen Brain Malformations Gene Curation Expert Panel classified the ASPM–autosomal recessive primary microcephaly relationship as Definitive on 2024-03-14.
Show evidence (1 reference)
"The diagnosis of ASPM-MCPH is established in a proband with biallelic pathogenic variants in ASPM identified by molecular genetic testing."
GeneReviews independently supports the curated ASPM disease relationship.
ClinGen CDK5RAP2–autosomal recessive primary microcephaly validity
The ClinGen Brain Malformations Gene Curation Expert Panel classified the CDK5RAP2–autosomal recessive primary microcephaly relationship as Definitive on 2022-01-25.
Show evidence (1 reference)
"Patient-derived Hi-Q brain organoids recapitulate distinct forms of developmental defects: primary microcephaly due to a mutation in CDK5RAP2"
Patient-derived organoids independently model the curated CDK5RAP2 disease relationship.
ClinGen WDR62–MCPH2 validity
The ClinGen Brain Malformations Gene Curation Expert Panel classified the WDR62–MCPH2 relationship as Definitive on 2020-05-26.
Show evidence (1 reference)
"The diagnosis of WDR62-MCPH is established in a proband with suggestive clinical findings and biallelic pathogenic variants in WDR62 identified by molecular genetic testing."
GeneReviews independently supports the curated WDR62 disease relationship.
ClinGen CENPJ–microcephaly 6 with or without short stature validity
The ClinGen Syndromic Disorders Gene Curation Expert Panel classified the CENPJ–microcephaly 6 with or without short stature relationship as Definitive on 2022-05-21. The asserted MONDO entity is narrower than this umbrella entry.
Show evidence (1 reference)
"MCPH6 Centromeric protein J CENPJ 13q12.2 609279"
The MCPH review independently maps MCPH6 to CENPJ.
Medical Actions
3
Multidisciplinary developmental and supportive care
Management is symptomatic and individualized. Developmental pediatrics, neurology, speech-language therapy, physical and occupational therapy, educational planning, behavioral support, and social-work services are coordinated according to functional needs. No disease-modifying therapy has established efficacy across MCPH.
Show evidence (1 reference)
"Treatment is symptomatic. Care by a multidisciplinary team (often including a pediatric neurologist, developmental pediatrician, speech-language pathologist, occupational and physical therapist, medical geneticist, and social worker) is recommended."
GeneReviews defines multidisciplinary symptomatic management for WDR62-MCPH.
Seizure and spasticity management
Epilepsy and spasticity are treated according to standard neurologic care, with surveillance for new seizures, treatment response, tone-related functional limitations, and therapy needs.
Show evidence (1 reference)
"The management of epilepsy and spasticity is per standard care."
ASPM GeneReviews directly supports standard symptom-directed management.
Genetic counseling and reproductive testing
Molecular subtype confirmation enables carrier testing for at-risk relatives, counseling about the 25% recurrence risk when both parents are carriers, targeted prenatal diagnosis, and preimplantation genetic testing.
Show evidence (1 reference)
"Once the ASPM pathogenic variants have been identified in an affected family member, carrier testing for at-risk relatives, prenatal testing for a pregnancy at increased risk, and preimplantation genetic testing are possible."
GeneReviews directly supports family testing and reproductive options.
Diagnosis
3
Head-circumference measurement and developmental phenotyping
Serial occipitofrontal-circumference measurements establish congenital or early primary microcephaly, while neurologic, developmental, behavioral, growth, and dysmorphology assessment determines whether the presentation is classic or syndromic.
Results: A markedly reduced head circumference present at birth or before age one, together with a compatible neurodevelopmental phenotype, supports primary microcephaly and prompts etiologic testing.
Show evidence (1 reference)
"usually present at birth and always present before age one year"
GeneReviews supplies a practical clinical recognition threshold and timing.
Brain magnetic resonance imaging
MRI characterizes brain volume, gyral simplification, callosal or infratentorial abnormalities, and subtype-associated malformations such as pachygyria, heterotopia, schizencephaly, or microlissencephaly.
magnetic resonance imaging procedure
NCIT:C16809
NCI Thesaurus (NCIT)
Results: A small brain with simplified gyration supports classic MCPH; major malformations refine subtype prioritization and prognosis.
Show evidence (1 reference)
"Brain malformations, including pachygyria, neuronal heterotopia, schizencephaly, and microlissencephaly, were present in 11 out of 15 patients."
Systematic MRI phenotyping identifies clinically important WDR62 malformations.
Molecular genetic testing
Because the umbrella is highly heterogeneous, a comprehensive microcephaly/neurodevelopmental panel, exome sequencing, or genome sequencing is generally more efficient than sequential single-gene testing. Copy-number analysis and segregation studies should be considered according to presentation and assay design.
molecular genetic testing
NCIT:C19770
NCI Thesaurus (NCIT)
Results: Biallelic pathogenic variants in a recognized MCPH gene establish a molecular subtype and enable recurrence-risk counseling, carrier testing, prenatal diagnosis, and preimplantation genetic testing.
Show evidence (2 references)
"Exome sequencing was performed on probands, 52 of whom had consanguineous parents. The diagnostic yield was 53.1%."
A contemporary 87-patient cohort demonstrates the utility of exome sequencing.
"The diagnosis of ASPM-MCPH is established in a proband with biallelic pathogenic variants in ASPM identified by molecular genetic testing."
GeneReviews defines molecular confirmation for the common ASPM subtype.
Progression
2Prenatal brain-growth restriction
The defining brain-growth deficit begins prenatally; microcephaly is usually apparent at birth, although WDR62-related disease can become evident during the first year.
Show evidence (1 reference)
"usually present at birth and always present before age one year"
GeneReviews defines the early course of ASPM-related MCPH.
Lifelong neurodevelopmental course
Cognitive, communication, motor, behavioral, and epilepsy needs require longitudinal surveillance. Most disease reflects a developmental deficit, but subtype-specific progression can occur.
Show evidence (1 reference)
"We identified progressive ataxia in the second decade of life in one patient, which should encourage clinicians to follow up patients in the long term."
The WDR62 cohort identifies a progressive late complication and supports long-term follow-up.
Prevalence
2General population
This is a literature estimate for MCPH as a group, not a registry-derived prevalence for every subtype.
Show evidence (1 reference)
"The prevalence of MCPH differs from 1:10,000 in populations with a high rate of consanguineous marriage to 1:250,000 in the general population"
The review provides the general-population estimate.
Populations with a high rate of consanguineous marriage
The elevated estimate reflects population structure and recessive inheritance; it should not be generalized to all populations.
Show evidence (1 reference)
"The prevalence of MCPH differs from 1:10,000 in populations with a high rate of consanguineous marriage to 1:250,000 in the general population"
The review provides the high-consanguinity population estimate.
Clinical Burden
Variable
Functional impact ranges from relatively preserved daily autonomy with borderline or mild intellectual disability to severe developmental disability, epilepsy, spasticity, ataxia, and major cortical malformations. Burden is strongly genotype- and variant-dependent.
Show evidence (2 references)
"Intellectual disability was severe in four patients, moderate in four, and mild in three."
A systematically assessed WDR62 cohort demonstrates wide variation in cognitive burden.
"In the MCPH group, borderline to mild intellectual disability, independent of microcephaly severity, and behavioral abnormalities were prominent"
A contemporary cohort documents the milder end of the MCPH functional spectrum.
Differential Diagnoses
3Conditions with similar clinical presentations that must be differentiated from Autosomal Recessive Primary Microcephaly:
Syndromic primary microcephaly
Overlapping Features
Many Mendelian syndromes cause prenatal microcephaly but have major extracranial anomalies or a broader malformation pattern and should not be automatically collapsed into classic MCPH.
Distinguishing Features
- Major congenital anomalies, disproportionate growth failure, metabolic disease, or multisystem involvement favor a syndromic diagnosis.
- Molecular testing assigns the causal disorder even when head-size severity overlaps.
Show evidence (1 reference)
"It differs from syndromic primary microcephaly (PM) by the lack of syndromic features and major brain malformations."
The cohort explicitly distinguishes classic MCPH from syndromic primary microcephaly.
Secondary or acquired microcephaly
Overlapping Features
Postnatal brain-growth deceleration or atrophy can follow infection, hypoxic-ischemic injury, teratogenic exposure, metabolic disease, or neurodegeneration and requires an exposure, imaging, and temporal workup.
Distinguishing Features
- Normal head size at birth followed by deceleration favors secondary microcephaly.
- Brain atrophy, destructive lesions, or a documented acquired insult weighs against classic MCPH.
Show evidence (1 reference)
"Microcephaly or reduced head circumference results from a multitude of abnormal developmental processes affecting brain growth and/or leading to brain atrophy."
The review frames impaired prenatal growth and brain atrophy as distinct etiologic routes.
Other genetic primary-microcephaly spectra
Overlapping Features
Dominant primary microcephalies, microcephalic primordial dwarfism, sensorineural syndromes, and broader malformations of cortical development overlap with MCPH but can have different inheritance, systemic findings, and disease boundaries.
Distinguishing Features
- Dominant or de novo inheritance argues against a numbered autosomal recessive MCPH subtype.
- Marked proportional short stature, sensory disease, or a major cortical-malformation pattern may indicate an adjacent disease spectrum.
Show evidence (1 reference)
"isolated PMs with or without malformations of cortical development and PMs associated with short stature (microcephalic dwarfism) or sensorineural disorders."
The review explicitly separates these overlapping primary-microcephaly categories.
Related Datasets
4
Distinct pathophysiological mechanisms of CEP152 variants in microcephaly and brain abnormalities
geo:GSE325064
Bulk RNA-sequencing of brains from Cep152 W105*/K897* and Q32P/Q32P patient-variant knock-in mice and matched controls, supporting analysis of variant-specific neuronal impairment.
Show evidence (1 reference)
"both Cep152W105*/K897* and Cep152Q32P/Q32P knock-in mice displayed microcephaly"
The associated publication supports the patient-variant mouse dataset.
Identifying new cellular mechanisms of MCPH5
geo:GSE244463
Developmental brain transcriptomes from Drosophila asp mutants, rescue animals, and wild-type controls across larval, pupal, and adult stages.
Show evidence (1 reference)
"we provide the neurodevelopmental transcriptional landscape for a Drosophila model for autosomal recessive primary microcephaly-5 (MCPH5)"
The associated publication defines the transcriptomic MCPH5 model.
A kinase-independent function of cyclin-dependent kinase 6 promotes outer radial glia expansion and neocortical folding
geo:GSE211990
Mouse cortical RNA-sequencing resource used to study CDK6-dependent outer-radial-glia expansion and neocortical folding.
Show evidence (1 reference)
"CDK6 loss selectively decreased oRGs and abolished neocortical folding."
The associated publication supports the CDK6 cortical model and its key phenotype.
Expression profiling analysis of mouse P4 cerebellum in CitK mutant mice proficient or knockout for P53
geo:GSE83465
Bulk RNA-sequencing of postnatal cerebellum across CitK and Trp53 genotypes, designed to distinguish TP53-dependent from TP53-independent responses to cytokinesis failure.
Show evidence (1 reference)
"transcriptional responses induced by ZIKV in human neural progenitors and those elicited by three different genetic mutations leading to severe forms of microcephaly in mice."
The associated publication describes the comparative transcriptional design that includes CitK-deficient mice.
Clinical Trials
1
NCT01565005
NOT_APPLICABLE
COMPLETED
This completed observational study compared neuroradiologic and cognitive phenotypes across genetically defined MCPH groups and Fanconi anemia. It enrolled 98 participants and was not a disease-modifying intervention. ClinicalTrials.gov was audited on 2026-07-23; no MCPH-specific interventional efficacy study was identified.
Show evidence (1 reference)
"Compare neuroradiological phenotype and cognitive functioning of MCPH patients caused by ASPM mutations already characterized and published (Passemard et al. 2009a) with other MCPH-related patients"
The registry record establishes the study's genotype-phenotype observational purpose.
Experimental Models
4
WDR62 patient-derived neural progenitor and cerebral organoid models
ORGANOID
namo:Organoid
These models resolve WDR62 movement from the Golgi to spindle poles and reproduce delayed mitosis, altered division orientation, premature differentiation, and changed neuronal trajectories.
Organism
human
NCBITaxon:9606
NCBI Taxonomy (NCBITaxon)
Relation: this experimental model is built in this organism
This experimental model is built in human, annotated with Homo sapiens (NCBITaxon:9606). NCBITaxon:9606 is an organism from the NCBI Taxonomy.
Tissue
cerebral cortex
UBERON:0000956
Uberon multi-species anatomy ontology (UBERON)
Relation: this experimental model uses this anatomical location
This experimental model uses cerebral cortex (UBERON:0000956). UBERON:0000956 is an anatomical location from the Uberon multi-species anatomy ontology.
Cell source
Patient-derived, parental, and isogenic-corrected induced pluripotent stem cells
Culture
Two-dimensional neuroepithelial cultures and three-dimensional cerebral organoids
Publication
Pathograph links
Centrosome, Spindle, and Kinetochore Dysfunction
The system measures WDR62 localization and mitotic progression in human neural progenitors.
Show evidence (1 reference)
"WDR62 localizes to the Golgi apparatus during interphase in cultured cells and human fetal brain tissue, and translocates to the mitotic spindle poles in a microtubule-dependent manner."
The patient/isogenic model directly resolves WDR62 subcellular dynamics.
Neural-Progenitor Proliferation and Survival Failure
Cerebral organoids model altered division choice and premature neurogenesis.
Show evidence (1 reference)
"RG-like progenitors in Mut COs displayed asymmetric cell divisions more frequently, suggestive of premature differentiation"
The organoid directly demonstrates altered progenitor fate.
Show evidence (1 reference)
"Using induced Pluripotent Stem Cells (iPSCs) obtained from a patient and his unaffected parent, as well as isogenic corrected lines, we generated 2D and 3D models of human neurodevelopment"
The paper defines the patient-derived and isogenic model system.
CIT kinase-dead and frameshift human forebrain organoids
ORGANOID
namo:Organoid
Both allelic organoids lose pseudostratified cytoarchitecture and show cytokinesis-polarity defects plus apoptosis, revealing a human phenotype not fully reproduced by the kinase-dead mouse.
Organism
human
NCBITaxon:9606
NCBI Taxonomy (NCBITaxon)
Relation: this experimental model is built in this organism
This experimental model is built in human, annotated with Homo sapiens (NCBITaxon:9606). NCBITaxon:9606 is an organism from the NCBI Taxonomy.
Tissue
forebrain
UBERON:0001890
Uberon multi-species anatomy ontology (UBERON)
Relation: this experimental model uses this anatomical location
This experimental model uses forebrain (UBERON:0001890). UBERON:0001890 is an anatomical location from the Uberon multi-species anatomy ontology.
Cell source
Gene-edited human pluripotent stem cells carrying CIT kinase-dead or frameshift alleles
Culture
Three-dimensional forebrain organoid
Publication
Pathograph links
Cytokinesis and Membrane-Trafficking Dysfunction
The organoids resolve CIT catalytic and scaffolding requirements during neural-progenitor cytokinesis.
Show evidence (1 reference)
"This change was associated with defects that disrupted the polarity of NPC cytokinesis, in addition to elevating apoptosis."
Human forebrain organoids directly reproduce the cytokinesis-polarity defect.
Show evidence (1 reference)
"CITKI/KI and CITFS/FS organoids lost cytoarchitectural complexity, transitioning from pseudostratified to simple neuroepithelium."
The primary study documents the organoid cytoarchitectural phenotype.
CETN3-knockout human cerebral organoids
ORGANOID
namo:Organoid
CETN3-knockout organoids are smaller and show impaired centrosome assembly, reduced progenitor proliferation, altered differentiation, apoptosis, and RNA-splicing changes.
Organism
human
NCBITaxon:9606
NCBI Taxonomy (NCBITaxon)
Relation: this experimental model is built in this organism
This experimental model is built in human, annotated with Homo sapiens (NCBITaxon:9606). NCBITaxon:9606 is an organism from the NCBI Taxonomy.
Tissue
cerebral cortex
UBERON:0000956
Uberon multi-species anatomy ontology (UBERON)
Relation: this experimental model uses this anatomical location
This experimental model uses cerebral cortex (UBERON:0000956). UBERON:0000956 is an anatomical location from the Uberon multi-species anatomy ontology.
Cell source
CETN3-knockout human pluripotent stem cells
Culture
Three-dimensional cerebral organoid
Publication
Pathograph links
Centrosome, Spindle, and Kinetochore Dysfunction
The organoids test how CETN3 loss impairs centrosome assembly and progenitor cell-cycle progression.
Show evidence (1 reference)
"CETN3 deficiency directly interferes with neuronal differentiation and reduces proliferative capacity in neural stem/progenitor cells by impairing centrosome assembly required in cell cycle progression, consequently activating apoptosis."
The organoid study directly resolves the centrosome-to-progenitor mechanism.
Show evidence (1 reference)
"CETN3-knockout (KO) organoids successfully recapitulated the microcephaly phenotype of reduced size compared to the control organoids."
The study directly documents disease-phenotype recapitulation.
CDK5RAP2 patient-derived high-quantity brain organoids
ORGANOID
namo:Organoid
The Hi-Q platform generates large numbers of reproducible, low-stress organoids and recapitulates CDK5RAP2-associated primary microcephaly, supporting scalable mechanism studies and future screening.
Organism
human
NCBITaxon:9606
NCBI Taxonomy (NCBITaxon)
Relation: this experimental model is built in this organism
This experimental model is built in human, annotated with Homo sapiens (NCBITaxon:9606). NCBITaxon:9606 is an organism from the NCBI Taxonomy.
Tissue
brain
UBERON:0000955
Uberon multi-species anatomy ontology (UBERON)
Relation: this experimental model uses this anatomical location
This experimental model uses brain (UBERON:0000955). UBERON:0000955 is an anatomical location from the Uberon multi-species anatomy ontology.
Cell source
Patient-derived human induced pluripotent stem cells with a CDK5RAP2 mutation
Culture
Scalable high-quantity brain organoid platform
Publication
Pathograph links
Neural-Progenitor Proliferation and Survival Failure
The platform models the patient-specific developmental defect at reproducible scale.
Show evidence (1 reference)
"Patient-derived Hi-Q brain organoids recapitulate distinct forms of developmental defects: primary microcephaly due to a mutation in CDK5RAP2"
The study directly demonstrates recapitulation of CDK5RAP2 microcephaly.
Show evidence (1 reference)
"These High Quantity brain organoids (Hi-Q brain organoids) exhibit reproducible cytoarchitecture, cell diversity, and functionality, are free from ectopically active cellular stress pathways, and allow cryopreservation and re-culturing."
The paper defines the platform's reproducibility and quality advantages.
Animal Models
5
Germline Aspm knockout ferret (Mustela putorius furo)
Germline loss-of-function model
The gyrencephalic ferret model develops severe microcephaly, altered neural-progenitor proportions, and increased apoptosis. Its outer subventricular zone makes it a useful bridge between lissencephalic rodents and human cortical development.
Species
ferret (Mustela putorius furo)
Genotype
Germline Aspm knockout
Genes
Show evidence (1 reference)
"Aspm germline knockout ferret 8. Severe microcephaly, displaced and altered NPC proportions, increased number of IPCs, increased apoptosis"
The MCPH review summarizes the gyrencephalic Aspm-null ferret phenotype.
Wdr62 germline loss-of-function mouse (Mus musculus)
Germline loss-of-function model
Wdr62-null mice show mild microcephaly, reduced neural-progenitor number, impaired mitosis, apoptosis, and altered cilium length, recapitulating some but not all human MCPH2 features.
Species
mouse (Mus musculus)
Genotype
Wdr62 germline loss-of-function
Genes
Show evidence (1 reference)
"Mild microcephaly, reduced NPC number, impaired mitosis, increased apoptosis, increased cilium length"
The review summarizes the Wdr62-null mouse phenotype.
Cit kinase-dead or frameshift loss-of-function knock-in mouse (Mus musculus)
Allelic knock-in models
Frameshift Cit loss phenocopies microcephaly more closely than kinase-dead Cit in mice, although both models show binucleation, DNA damage, and apoptosis. This allelic difference exposes an important species/model limitation.
Species
mouse (Mus musculus)
Genotype
Cit kinase-dead or frameshift loss-of-function knock-in
Genes
Show evidence (1 reference)
"we created the CitKI/KI mouse model and found that it did not phenocopy human microcephaly, unlike biallelic CitFS/FS animals. Nevertheless, both Cit models exhibited binucleation, DNA damage, and apoptosis."
The primary study documents allelic and species-specific model behavior.
rrp7a mutation zebrafish (Danio rerio)
Germline loss-of-function model
Mutant zebrafish show reduced brain size, impaired neurogenesis and proliferation, and defective ribosomal RNA processing.
Species
zebrafish (Danio rerio)
Genotype
rrp7a mutation
Genes
Show evidence (1 reference)
"Analysis of zebrafish embryos supported that the patient mutation in RRP7A causes reduced brain size, impaired neurogenesis and cell proliferation, and defective ribosomal RNA processing."
The discovery study directly summarizes the zebrafish phenotype.
Cep152 compound-heterozygous truncating or homozygous Q32P knock-in mouse (Mus musculus)
Patient-variant knock-in models
Both Cep152 genotypes produce microcephaly, while the Q32P model has more severe cortical defects, centrosome abnormalities, mitotic errors, and apoptosis, supporting variant-specific mechanisms and severity.
Species
mouse (Mus musculus)
Genotype
Cep152 compound-heterozygous truncating or homozygous Q32P knock-in
Genes
Show evidence (1 reference)
"both Cep152W105*/K897* and Cep152Q32P/Q32P knock-in mice displayed microcephaly; notably, Cep152Q32P/Q32P mice also exhibited severe cortical defects during brain development."
Patient-variant knock-in mice demonstrate genotype-specific severity.
Source YAML
click to showname: Autosomal Recessive Primary Microcephaly
creation_date: "2026-05-13T12:00:00Z"
category: Mendelian
description: >-
Autosomal recessive primary microcephaly (MCPH) is a genetically
heterogeneous group of prenatal brain-growth disorders characterized by
primary microcephaly and usually intellectual or developmental impairment.
The classic phenotype has a small cerebral cortex with simplified gyration
and few major extracranial anomalies, but individual genetic subtypes can
include cortical malformations, spasticity, epilepsy, ataxia, short stature,
or other syndromic features. Biallelic variants disrupt multiple processes
needed to expand the fetal neural-progenitor pool, including centrosome and
spindle organization, chromosome segregation and DNA repair, cytokinesis,
membrane trafficking, lipid transport, ribosome biogenesis, and ciliary
dynamics. These lesions converge variably on mitotic delay, DNA damage,
TP53-linked apoptosis, premature differentiation, and reduced cortical-neuron
output.
synonyms:
- MCPH
- microcephaly primary hereditary
- primary hereditary microcephaly
- autosomal recessive primary microcephaly
- microcephaly vera
parents:
- Microcephaly
- Mendelian Disorder
- Neurological Disorder
disease_term:
preferred_term: autosomal recessive primary microcephaly
term:
id: MONDO:0016660
label: autosomal recessive primary microcephaly
mappings:
mondo_mappings:
- term:
id: MONDO:0016660
label: autosomal recessive primary microcephaly
mapping_predicate: skos:exactMatch
mapping_source: MONDO
notes: >-
This entry follows the current MONDO:0016660 hierarchy rather than assuming
that every historically numbered MCPH locus remains within one disease
umbrella. The current hierarchy contains 28 descendants: MCPH1-MCPH17,
MCPH19-MCPH25, and MCPH28-MCPH31. MCPH18 (WDFY3), MCPH26 (LMNB1), and MCPH27
(LMNB2) are not current descendants and are therefore not asserted as
subtypes here. Conversely, the hierarchy includes a ZNF335-associated
microcephalic primordial-dwarfism entity, illustrating that the ontology
umbrella extends beyond the narrowest “isolated classic MCPH” phenotype.
clinical_burden:
burden_level: VARIABLE
rationale: >-
Functional impact ranges from relatively preserved daily autonomy with
borderline or mild intellectual disability to severe developmental
disability, epilepsy, spasticity, ataxia, and major cortical
malformations. Burden is strongly genotype- and variant-dependent.
evidence:
- reference: PMID:35726608
reference_title: Neurological outcome in WDR62 primary microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Intellectual disability was severe in four patients, moderate in four,
and mild in three.
explanation: A systematically assessed WDR62 cohort demonstrates wide variation in cognitive burden.
- reference: PMID:42141383
reference_title: "Elucidating the Genetic Landscape, Phenotypic Spectrum, and Pathogenic Mechanisms in a Turkish Cohort with Primary Microcephaly."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In the MCPH group, borderline to mild intellectual disability,
independent of microcephaly severity, and behavioral abnormalities were
prominent
explanation: A contemporary cohort documents the milder end of the MCPH functional spectrum.
inheritance:
- name: Autosomal recessive inheritance
description: >-
The numbered MCPH entities in this entry are caused by biallelic pathogenic
variants. For a couple who are both heterozygous for the same
disease-causing gene, each pregnancy has a 25% affected recurrence risk.
inheritance_term:
preferred_term: Autosomal recessive inheritance
term:
id: HP:0000007
label: Autosomal recessive inheritance
evidence:
- reference: PMID:32239881
reference_title: ASPM Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "ASPM-MCPH is inherited in an autosomal recessive manner."
explanation: GeneReviews explicitly states autosomal recessive inheritance for the most common MCPH subtype.
- reference: PMID:35188728
reference_title: WDR62 Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "WDR62-MCPH is inherited in an autosomal recessive manner."
explanation: GeneReviews independently confirms recessive inheritance for MCPH2.
prevalence:
- population: General population
measure_type: POINT_PREVALENCE
prevalence_class: BAND_1_9_PER_1000000
rate_per_100000: 0.4
notes: >-
This is a literature estimate for MCPH as a group, not a registry-derived
prevalence for every subtype.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The prevalence of MCPH differs from 1:10,000 in populations with a high
rate of consanguineous marriage to 1:250,000 in the general population
explanation: The review provides the general-population estimate.
- population: Populations with a high rate of consanguineous marriage
measure_type: POINT_PREVALENCE
prevalence_class: BAND_1_5_PER_10000
rate_per_100000: 10
notes: >-
The elevated estimate reflects population structure and recessive
inheritance; it should not be generalized to all populations.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The prevalence of MCPH differs from 1:10,000 in populations with a high
rate of consanguineous marriage to 1:250,000 in the general population
explanation: The review provides the high-consanguinity population estimate.
progression:
- phase: Prenatal brain-growth restriction
age_range: Prenatal to birth
notes: >-
The defining brain-growth deficit begins prenatally; microcephaly is
usually apparent at birth, although WDR62-related disease can become
evident during the first year.
evidence:
- reference: PMID:32239881
reference_title: ASPM Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "usually present at birth and always present before age one year"
explanation: GeneReviews defines the early course of ASPM-related MCPH.
- phase: Lifelong neurodevelopmental course
age_range: Childhood through adulthood
notes: >-
Cognitive, communication, motor, behavioral, and epilepsy needs require
longitudinal surveillance. Most disease reflects a developmental deficit,
but subtype-specific progression can occur.
evidence:
- reference: PMID:35726608
reference_title: Neurological outcome in WDR62 primary microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We identified progressive ataxia in the second decade of life in one
patient, which should encourage clinicians to follow up patients in the
long term.
explanation: The WDR62 cohort identifies a progressive late complication and supports long-term follow-up.
has_subtypes:
- name: MCPH1
display_name: MCPH1 (MCPH1)
description: Biallelic MCPH1 variants cause the MCPH1 subtype.
subtype_term:
preferred_term: microcephaly 1, primary, autosomal recessive
term:
id: MONDO:0009617
label: microcephaly 1, primary, autosomal recessive
genes:
- preferred_term: MCPH1
term:
id: hgnc:6954
label: MCPH1
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH1 Microcephalin 1 MCPH1 8p23.1 607117"
explanation: The review's MCPH table maps the MCPH1 locus to MCPH1.
- name: MCPH2
display_name: MCPH2 (WDR62)
description: Biallelic WDR62 variants cause MCPH2, often with additional cortical malformations.
subtype_term:
preferred_term: microcephaly 2, primary, autosomal recessive, with or without cortical malformations
term:
id: MONDO:0011435
label: microcephaly 2, primary, autosomal recessive, with or without cortical malformations
genes:
- preferred_term: WDR62
term:
id: hgnc:24502
label: WDR62
evidence:
- reference: PMID:35188728
reference_title: WDR62 Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The diagnosis of WDR62-MCPH is established in a proband with suggestive
clinical findings and biallelic pathogenic variants in WDR62 identified
by molecular genetic testing.
explanation: GeneReviews establishes the biallelic WDR62 basis of MCPH2.
- name: MCPH3
display_name: MCPH3 (CDK5RAP2)
description: Biallelic CDK5RAP2 variants cause the MCPH3 subtype.
subtype_term:
preferred_term: microcephaly 3, primary, autosomal recessive
term:
id: MONDO:0011488
label: microcephaly 3, primary, autosomal recessive
genes:
- preferred_term: CDK5RAP2
term:
id: hgnc:18672
label: CDK5RAP2
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH3 Cyclin-dependent kinase 5 regulatory subunit-associated protein 2 CDK5RAP2 9q33.2 608201"
explanation: The review's MCPH table maps MCPH3 to CDK5RAP2.
- name: MCPH4
display_name: MCPH4 (KNL1)
description: Biallelic KNL1 variants cause the MCPH4 subtype.
subtype_term:
preferred_term: microcephaly 4, primary, autosomal recessive
term:
id: MONDO:0011437
label: microcephaly 4, primary, autosomal recessive
genes:
- preferred_term: KNL1
term:
id: hgnc:24054
label: KNL1
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH4 Kinetochore scaffold 1 KNL1 15q15.1 609173"
explanation: The review's MCPH table maps MCPH4 to KNL1.
- name: MCPH5
display_name: MCPH5 (ASPM)
description: Biallelic ASPM variants cause MCPH5, the most common classic subtype.
subtype_term:
preferred_term: microcephaly 5, primary, autosomal recessive
term:
id: MONDO:0012106
label: microcephaly 5, primary, autosomal recessive
genes:
- preferred_term: ASPM
term:
id: hgnc:19048
label: ASPM
evidence:
- reference: PMID:32239881
reference_title: ASPM Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The diagnosis of ASPM-MCPH is established in a proband with biallelic
pathogenic variants in ASPM identified by molecular genetic testing.
explanation: GeneReviews establishes the biallelic ASPM basis of MCPH5.
- name: MCPH6
display_name: MCPH6 (CENPJ)
description: Biallelic CENPJ variants cause the MCPH6 subtype.
subtype_term:
preferred_term: microcephaly 6, primary, autosomal recessive
term:
id: MONDO:0012029
label: microcephaly 6, primary, autosomal recessive
genes:
- preferred_term: CENPJ
term:
id: hgnc:17272
label: CENPJ
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH6 Centromeric protein J CENPJ 13q12.2 609279"
explanation: The review's MCPH table maps MCPH6 to CENPJ.
- name: MCPH7
display_name: MCPH7 (STIL)
description: Biallelic STIL variants cause the MCPH7 subtype.
subtype_term:
preferred_term: microcephaly 7, primary, autosomal recessive
term:
id: MONDO:0012989
label: microcephaly 7, primary, autosomal recessive
genes:
- preferred_term: STIL
term:
id: hgnc:10879
label: STIL
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH7 SCL/TAL1- interrupting locus protein STIL 1p33 181590"
explanation: The review's MCPH table maps MCPH7 to STIL.
- name: MCPH8
display_name: MCPH8 (CEP135)
description: Biallelic CEP135 variants cause the MCPH8 subtype.
subtype_term:
preferred_term: microcephaly 8, primary, autosomal recessive
term:
id: MONDO:0013849
label: microcephaly 8, primary, autosomal recessive
genes:
- preferred_term: CEP135
term:
id: hgnc:29086
label: CEP135
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH8 Centrosomal protein 135 kD CEP135 4q12 611423"
explanation: The review's MCPH table maps MCPH8 to CEP135.
- name: MCPH9
display_name: MCPH9 (CEP152)
description: Biallelic CEP152 variants cause the MCPH9 subtype.
subtype_term:
preferred_term: microcephaly 9, primary, autosomal recessive
term:
id: MONDO:0013923
label: microcephaly 9, primary, autosomal recessive
genes:
- preferred_term: CEP152
term:
id: hgnc:29298
label: CEP152
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH9 Centrosomal protein 152 kD CEP152 15q21.1 613529"
explanation: The review's MCPH table maps MCPH9 to CEP152.
- name: MCPH10
display_name: MCPH10 (ZNF335)
description: >-
Biallelic ZNF335 variants cause the current MONDO child named
microcephalic primordial dwarfism due to ZNF335 deficiency.
subtype_term:
preferred_term: microcephalic primordial dwarfism due to ZNF335 deficiency
term:
id: MONDO:0014043
label: microcephalic primordial dwarfism due to ZNF335 deficiency
genes:
- preferred_term: ZNF335
term:
id: hgnc:15807
label: ZNF335
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "ZNF335; MCPH10"
explanation: The review's MCPH table maps MCPH10 to ZNF335.
- name: MCPH11
display_name: MCPH11 (PHC1)
description: Biallelic PHC1 variants cause the MCPH11 subtype.
subtype_term:
preferred_term: microcephaly 11, primary, autosomal recessive
term:
id: MONDO:0014173
label: microcephaly 11, primary, autosomal recessive
genes:
- preferred_term: PHC1
term:
id: hgnc:3182
label: PHC1
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH11 Polyhomeotic-like 1 protein PHC1 12p13.31 602978"
explanation: The review's MCPH table maps MCPH11 to PHC1.
- name: MCPH12
display_name: MCPH12 (CDK6)
description: Biallelic CDK6 variants cause the MCPH12 subtype.
subtype_term:
preferred_term: microcephaly 12, primary, autosomal recessive
term:
id: MONDO:0014484
label: microcephaly 12, primary, autosomal recessive
genes:
- preferred_term: CDK6
term:
id: hgnc:1777
label: CDK6
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH12 Cyclin-dependent kinase 6 CDK6 7q21.2 603368"
explanation: The review's MCPH table maps MCPH12 to CDK6.
- name: MCPH13
display_name: MCPH13 (CENPE)
description: Biallelic CENPE variants cause the MCPH13 subtype.
subtype_term:
preferred_term: microcephaly 13, primary, autosomal recessive
term:
id: MONDO:0014473
label: microcephaly 13, primary, autosomal recessive
genes:
- preferred_term: CENPE
term:
id: hgnc:1856
label: CENPE
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH13 Centromeric protein E CENPE 4q24 117143"
explanation: The review's MCPH table maps MCPH13 to CENPE.
- name: MCPH14
display_name: MCPH14 (SASS6)
description: Biallelic SASS6 variants cause the MCPH14 subtype.
subtype_term:
preferred_term: microcephaly 14, primary, autosomal recessive
term:
id: MONDO:0014623
label: microcephaly 14, primary, autosomal recessive
genes:
- preferred_term: SASS6
term:
id: hgnc:25403
label: SASS6
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH14 SAS-6 centriolar assembly protein SASS6 1p21.2 609321"
explanation: The review's MCPH table maps MCPH14 to SASS6.
- name: MCPH15
display_name: MCPH15 (MFSD2A)
description: Biallelic MFSD2A variants cause the MCPH15 subtype.
subtype_term:
preferred_term: microcephaly 15, primary, autosomal recessive
term:
id: MONDO:0014660
label: microcephaly 15, primary, autosomal recessive
genes:
- preferred_term: MFSD2A
term:
id: hgnc:25897
label: MFSD2A
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH15 Major facilitator superfamily domain- containing protein 2A MFSD2A 1p34.2 614397"
explanation: The review's MCPH table maps MCPH15 to MFSD2A.
- name: MCPH16
display_name: MCPH16 (ANKLE2)
description: Biallelic ANKLE2 variants cause the MCPH16 subtype.
subtype_term:
preferred_term: microcephaly 16, primary, autosomal recessive
term:
id: MONDO:0014730
label: microcephaly 16, primary, autosomal recessive
genes:
- preferred_term: ANKLE2
term:
id: hgnc:29101
label: ANKLE2
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH16 ANKLE2 12q24.33 616062"
explanation: The review's MCPH table maps MCPH16 to ANKLE2.
- name: MCPH17
display_name: MCPH17 (CIT)
description: Biallelic CIT variants cause MCPH17 through cytokinesis dysfunction.
subtype_term:
preferred_term: microcephaly 17, primary, autosomal recessive
term:
id: MONDO:0014908
label: microcephaly 17, primary, autosomal recessive
genes:
- preferred_term: CIT
term:
id: hgnc:1985
label: CIT
evidence:
- reference: PMID:39316437
reference_title: Modeling primary microcephaly with human brain organoids reveals fundamental roles of CIT kinase activity.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Biallelic citron rho-interacting serine/threonine kinase (CIT) missense
variants that disrupt kinase function (CITKI/KI) and frameshift
loss-of-function variants (CITFS/FS) are the genetic basis for MCPH17
explanation: Human genetic and functional work directly establishes CIT as the MCPH17 gene.
- name: MCPH19
display_name: MCPH19 (COPB2)
description: Biallelic COPB2 variants cause the MCPH19 subtype.
subtype_term:
preferred_term: microcephaly 19, primary, autosomal recessive
term:
id: MONDO:0054716
label: microcephaly 19, primary, autosomal recessive
genes:
- preferred_term: COPB2
term:
id: hgnc:2232
label: COPB2
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH19 Coatomer protein complex, subunit beta 2 (beta prime) COPB2 3q23 606990"
explanation: The review's MCPH table maps MCPH19 to COPB2.
- name: MCPH20
display_name: MCPH20 (KIF14)
description: Biallelic KIF14 variants cause the MCPH20 subtype.
subtype_term:
preferred_term: microcephaly 20, primary, autosomal recessive
term:
id: MONDO:0054761
label: microcephaly 20, primary, autosomal recessive
genes:
- preferred_term: KIF14
term:
id: hgnc:19181
label: KIF14
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH20 Kinesin family member 14 KIF14 1q32.1 611279"
explanation: The review's MCPH table maps MCPH20 to KIF14.
- name: MCPH21
display_name: MCPH21 (NCAPD2)
description: Biallelic NCAPD2 variants cause the MCPH21 subtype.
subtype_term:
preferred_term: microcephaly 21, primary, autosomal recessive
term:
id: MONDO:0054804
label: microcephaly 21, primary, autosomal recessive
genes:
- preferred_term: NCAPD2
term:
id: hgnc:24305
label: NCAPD2
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH21 Non-SMC condensin I complex, subunit D2 NCAPD2 12p13.31 615638"
explanation: The review's MCPH table maps MCPH21 to NCAPD2.
- name: MCPH22
display_name: MCPH22 (NCAPD3)
description: Biallelic NCAPD3 variants cause the MCPH22 subtype.
subtype_term:
preferred_term: microcephaly 22, primary, autosomal recessive
term:
id: MONDO:0054805
label: microcephaly 22, primary, autosomal recessive
genes:
- preferred_term: NCAPD3
term:
id: hgnc:28952
label: NCAPD3
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH22 Non-SMC condensin II complex subunit D3 NCAPD3 11q25 609276"
explanation: The review's MCPH table maps MCPH22 to NCAPD3.
- name: MCPH23
display_name: MCPH23 (NCAPH)
description: Biallelic NCAPH variants cause the MCPH23 subtype.
subtype_term:
preferred_term: microcephaly 23, primary, autosomal recessive
term:
id: MONDO:0054806
label: microcephaly 23, primary, autosomal recessive
genes:
- preferred_term: NCAPH
term:
id: hgnc:1112
label: NCAPH
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH23 Non-SMC condensin I complex subunit H NCAPH 2q11.2 602332"
explanation: The review's MCPH table maps MCPH23 to NCAPH.
- name: MCPH24
display_name: MCPH24 (NUP37)
description: Biallelic NUP37 variants cause the MCPH24 subtype.
subtype_term:
preferred_term: microcephaly 24, primary, autosomal recessive
term:
id: MONDO:0032583
label: microcephaly 24, primary, autosomal recessive
genes:
- preferred_term: NUP37
term:
id: hgnc:29929
label: NUP37
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH24 Nucleoporin 37 NUP37 12q23.2 609264"
explanation: The review's MCPH table maps MCPH24 to NUP37.
- name: MCPH25
display_name: MCPH25 (TRAPPC14)
description: Biallelic TRAPPC14 variants cause the MCPH25 subtype.
subtype_term:
preferred_term: microcephaly 25, primary, autosomal recessive
term:
id: MONDO:0032694
label: microcephaly 25, primary, autosomal recessive
genes:
- preferred_term: TRAPPC14
term:
id: hgnc:25604
label: TRAPPC14
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "TRAPPC14 mutations have been linked to MCPH25 in human"
explanation: The review's MCPH table maps MCPH25 to TRAPPC14.
- name: MCPH28
display_name: MCPH28 (RRP7A)
description: Biallelic RRP7A variants cause MCPH28 through ribosome, cilium, and cell-cycle dysfunction.
subtype_term:
preferred_term: microcephaly 28, primary, autosomal recessive
term:
id: MONDO:0030339
label: microcephaly 28, primary, autosomal recessive
genes:
- preferred_term: RRP7A
term:
id: hgnc:24286
label: RRP7A
evidence:
- reference: PMID:33199730
reference_title: "RRP7A links primary microcephaly to dysfunction of ribosome biogenesis, resorption of primary cilia, and neurogenesis."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We identified a homozygous missense mutation (p.W155C) in Ribosomal RNA
Processing 7 Homolog A, RRP7A, segregating with MCPH in a consanguineous
family with 10 affected individuals.
explanation: The discovery study establishes recessive RRP7A-associated MCPH.
- name: MCPH29
display_name: MCPH29 (PDCD6IP)
description: Biallelic PDCD6IP variants cause the current MCPH29 subtype.
subtype_term:
preferred_term: microcephaly 29, primary, autosomal recessive
term:
id: MONDO:0031060
label: microcephaly 29, primary, autosomal recessive
genes:
- preferred_term: PDCD6IP
term:
id: hgnc:8766
label: PDCD6IP
evidence:
- reference: PMID:32286682
reference_title: "PDCD6IP, encoding a regulator of the ESCRT complex, is mutated in microcephaly."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We report a consanguineous family with PM, intellectual disability and
short stature. Using whole exome sequencing, we identified a homozygous
frameshift variant in programmed cell death 6 interacting protein
explanation: The discovery family supports biallelic PDCD6IP as a primary-microcephaly cause.
- name: MCPH30
display_name: MCPH30 (BUB1)
description: >-
Biallelic BUB1 variants cause the current MCPH30 subtype; the discovery
paper emphasized overlap with MCPH, aneuploidy syndromes, and cohesinopathies.
subtype_term:
preferred_term: microcephaly 30, primary, autosomal recessive
term:
id: MONDO:0859342
label: microcephaly 30, primary, autosomal recessive
genes:
- preferred_term: BUB1
term:
id: hgnc:1148
label: BUB1
evidence:
- reference: PMID:35044816
reference_title: "Biallelic BUB1 mutations cause microcephaly, developmental delay, and variable effects on cohesion and chromosome segregation."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Here, we describe the first two patients with biallelic BUB1 germline
mutations, who both display microcephaly, intellectual disability, and
several patient-specific features.
explanation: The discovery report establishes the recessive BUB1 neurodevelopmental phenotype.
- name: MCPH31
display_name: MCPH31 (CETN3)
description: Biallelic loss-of-function CETN3 variants cause the current MCPH31 subtype.
subtype_term:
preferred_term: microcephaly 31, primary, autosomal recessive
term:
id: MONDO:0980991
label: microcephaly 31, primary, autosomal recessive
genes:
- preferred_term: CETN3
term:
id: hgnc:1868
label: CETN3
evidence:
- reference: PMID:40926052
reference_title: CETN3 deficiency induces microcephaly by disrupting neural stem/progenitor cell fate through impaired centrosome assembly and RNA splicing.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Through whole-exome sequencing, we identified compound heterozygous
loss-of-function mutations in CENTRIN 3 (CETN3) in a 5-year-old patient
with primary microcephaly.
explanation: The discovery and functional study establishes biallelic CETN3-associated primary microcephaly.
external_assertions:
- name: ClinGen ASPM–autosomal recessive primary microcephaly validity
source: ClinGen
assertion_type: gene_disease_validity
external_id: CGGV:assertion_41e82e1a-528f-48ee-9e07-22865077f61d-2024-03-14T170000.000Z
url: https://search.clinicalgenome.org/kb/gene-validity/CGGV:assertion_41e82e1a-528f-48ee-9e07-22865077f61d-2024-03-14T170000.000Z
description: >-
The ClinGen Brain Malformations Gene Curation Expert Panel classified the
ASPM–autosomal recessive primary microcephaly relationship as Definitive on
2024-03-14.
evidence:
- reference: PMID:32239881
reference_title: ASPM Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The diagnosis of ASPM-MCPH is established in a proband with biallelic
pathogenic variants in ASPM identified by molecular genetic testing.
explanation: GeneReviews independently supports the curated ASPM disease relationship.
- name: ClinGen CDK5RAP2–autosomal recessive primary microcephaly validity
source: ClinGen
assertion_type: gene_disease_validity
external_id: CGGV:assertion_70dace84-4d61-44f5-9de5-a81b5c70cad4-2022-01-25T170000.000Z
url: https://search.clinicalgenome.org/kb/gene-validity/CGGV:assertion_70dace84-4d61-44f5-9de5-a81b5c70cad4-2022-01-25T170000.000Z
description: >-
The ClinGen Brain Malformations Gene Curation Expert Panel classified the
CDK5RAP2–autosomal recessive primary microcephaly relationship as Definitive
on 2022-01-25.
evidence:
- reference: PMID:39702477
reference_title: "Reliability of high-quantity human brain organoids for modeling microcephaly, glioma invasion and drug screening."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
Patient-derived Hi-Q brain organoids recapitulate distinct forms of
developmental defects: primary microcephaly due to a mutation in
CDK5RAP2
explanation: Patient-derived organoids independently model the curated CDK5RAP2 disease relationship.
- name: ClinGen WDR62–MCPH2 validity
source: ClinGen
assertion_type: gene_disease_validity
external_id: CGGV:assertion_bdbcb9de-2ded-46a0-a6d0-16b34ea22008-2020-05-26T160000.000Z
url: https://search.clinicalgenome.org/kb/gene-validity/CGGV:assertion_bdbcb9de-2ded-46a0-a6d0-16b34ea22008-2020-05-26T160000.000Z
description: >-
The ClinGen Brain Malformations Gene Curation Expert Panel classified the
WDR62–MCPH2 relationship as Definitive on 2020-05-26.
evidence:
- reference: PMID:35188728
reference_title: WDR62 Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The diagnosis of WDR62-MCPH is established in a proband with suggestive
clinical findings and biallelic pathogenic variants in WDR62 identified
by molecular genetic testing.
explanation: GeneReviews independently supports the curated WDR62 disease relationship.
- name: ClinGen CENPJ–microcephaly 6 with or without short stature validity
source: ClinGen
assertion_type: gene_disease_validity
external_id: CGGV:assertion_c10510c1-2c0e-466e-928a-77d896159d06-2022-05-21T104414.354Z
url: https://search.clinicalgenome.org/kb/gene-validity/CGGV:assertion_c10510c1-2c0e-466e-928a-77d896159d06-2022-05-21T104414.354Z
description: >-
The ClinGen Syndromic Disorders Gene Curation Expert Panel classified the
CENPJ–microcephaly 6 with or without short stature relationship as
Definitive on 2022-05-21. The asserted MONDO entity is narrower than this
umbrella entry.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH6 Centromeric protein J CENPJ 13q12.2 609279"
explanation: The MCPH review independently maps MCPH6 to CENPJ.
pathophysiology:
- name: Heterogeneous Biallelic MCPH Gene Dysfunction
description: >-
Biallelic pathogenic variants in the current MONDO MCPH subtype genes
perturb several cellular systems that are essential for fetal
neural-progenitor expansion. The locus set is mechanistically
heterogeneous, so centrosome dysfunction is an important convergence point
rather than a complete explanation for every subtype.
genes:
- preferred_term: MCPH1
term:
id: hgnc:6954
label: MCPH1
- preferred_term: WDR62
term:
id: hgnc:24502
label: WDR62
- preferred_term: CDK5RAP2
term:
id: hgnc:18672
label: CDK5RAP2
- preferred_term: KNL1
term:
id: hgnc:24054
label: KNL1
- preferred_term: ASPM
term:
id: hgnc:19048
label: ASPM
- preferred_term: CENPJ
term:
id: hgnc:17272
label: CENPJ
- preferred_term: STIL
term:
id: hgnc:10879
label: STIL
- preferred_term: CEP135
term:
id: hgnc:29086
label: CEP135
- preferred_term: CEP152
term:
id: hgnc:29298
label: CEP152
- preferred_term: ZNF335
term:
id: hgnc:15807
label: ZNF335
- preferred_term: PHC1
term:
id: hgnc:3182
label: PHC1
- preferred_term: CDK6
term:
id: hgnc:1777
label: CDK6
- preferred_term: CENPE
term:
id: hgnc:1856
label: CENPE
- preferred_term: SASS6
term:
id: hgnc:25403
label: SASS6
- preferred_term: MFSD2A
term:
id: hgnc:25897
label: MFSD2A
- preferred_term: ANKLE2
term:
id: hgnc:29101
label: ANKLE2
- preferred_term: CIT
term:
id: hgnc:1985
label: CIT
- preferred_term: COPB2
term:
id: hgnc:2232
label: COPB2
- preferred_term: KIF14
term:
id: hgnc:19181
label: KIF14
- preferred_term: NCAPD2
term:
id: hgnc:24305
label: NCAPD2
- preferred_term: NCAPD3
term:
id: hgnc:28952
label: NCAPD3
- preferred_term: NCAPH
term:
id: hgnc:1112
label: NCAPH
- preferred_term: NUP37
term:
id: hgnc:29929
label: NUP37
- preferred_term: TRAPPC14
term:
id: hgnc:25604
label: TRAPPC14
- preferred_term: RRP7A
term:
id: hgnc:24286
label: RRP7A
- preferred_term: PDCD6IP
term:
id: hgnc:8766
label: PDCD6IP
- preferred_term: BUB1
term:
id: hgnc:1148
label: BUB1
- preferred_term: CETN3
term:
id: hgnc:1868
label: CETN3
cell_types:
- preferred_term: neural progenitor cell
term:
id: CL:0011020
label: neural progenitor cell
biological_processes:
- preferred_term: cell cycle
term:
id: GO:0007049
label: cell cycle
modifier: ABNORMAL
evidence:
- reference: PMID:37443841
reference_title: "Genetic Primary Microcephalies: When Centrosome Dysfunction Dictates Brain and Body Size."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Most are caused by biallelic or, more rarely, dominant mutations in one
of the likely hundreds of genes encoding PM proteins
explanation: The contemporary review establishes the genetically heterogeneous, usually biallelic basis of primary microcephalies.
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
MCPH proteins play crucial roles in microtubule dynamics, mitotic spindle
formation, DNA damage responses, Wnt signaling, transcriptional
regulation, and cell cycle checkpoint control
explanation: The review documents mechanistic heterogeneity across the MCPH locus series.
downstream:
- target: Centrosome, Spindle, and Kinetochore Dysfunction
causal_link_type: DIRECT
description: Many MCPH proteins directly build or regulate centrioles, centrosomes, spindle poles, microtubules, and kinetochores.
evidence:
- reference: PMID:37443841
reference_title: "Genetic Primary Microcephalies: When Centrosome Dysfunction Dictates Brain and Body Size."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
ubiquitous centrosome or microtubule-associated proteins required for
the division of neural progenitor cells in the embryonic brain
explanation: The review identifies the dominant centrosome/microtubule functional class.
- target: Chromatin, DNA Repair, and Condensin Dysfunction
causal_link_type: DIRECT
description: MCPH1, PHC1, ZNF335, condensin-subunit, and related defects disrupt genome organization or surveillance.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Mutations in genes encoding chromatin-linked proteins expand the
pathomechanism spectrum of the MCPH.
explanation: The review identifies chromatin dysfunction as a distinct MCPH mechanism.
- target: Cytokinesis and Membrane-Trafficking Dysfunction
causal_link_type: DIRECT
description: CIT, KIF14, PDCD6IP, COPB2, and TRAPPC14 perturb cytokinesis or membrane-trafficking machinery.
evidence:
- reference: PMID:32286682
reference_title: "PDCD6IP, encoding a regulator of the ESCRT complex, is mutated in microcephaly."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
PDCD6IP, plays an important role in the endosomal sorting complexes
required for transport (ESCRT) pathway in the abscission stage of
cytokinesis and apoptosis
explanation: The PDCD6IP discovery paper connects an MCPH gene to ESCRT-dependent abscission.
- target: Ribosome, Cilium, and Lipid-Transport Dysfunction
causal_link_type: DIRECT
description: RRP7A and MFSD2A illustrate noncanonical routes into impaired brain growth.
evidence:
- reference: PMID:33199730
reference_title: "RRP7A links primary microcephaly to dysfunction of ribosome biogenesis, resorption of primary cilia, and neurogenesis."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
patient-derived fibroblasts display defects in ribosomal RNA
processing, primary cilia resorption, and cell cycle progression.
explanation: Patient cells establish an RRP7A route through ribosome, cilium, and cell-cycle dysfunction.
- name: Centrosome, Spindle, and Kinetochore Dysfunction
conforms_to: neural_progenitor_centrosome_spindle_dysfunction#Centrosome and Mitotic Spindle Perturbation
description: >-
Defective centriole assembly, centrosome maturation, spindle-pole
organization, kinetochore function, or spindle orientation delays mitosis
and increases chromosome-segregation errors in dividing neural
progenitors. Individual genes affect different structures, so this node is
a mechanistic family rather than a claim of identical molecular lesions.
genes:
- preferred_term: WDR62
term:
id: hgnc:24502
label: WDR62
- preferred_term: CDK5RAP2
term:
id: hgnc:18672
label: CDK5RAP2
- preferred_term: KNL1
term:
id: hgnc:24054
label: KNL1
- preferred_term: ASPM
term:
id: hgnc:19048
label: ASPM
- preferred_term: CENPJ
term:
id: hgnc:17272
label: CENPJ
- preferred_term: STIL
term:
id: hgnc:10879
label: STIL
- preferred_term: CEP135
term:
id: hgnc:29086
label: CEP135
- preferred_term: CEP152
term:
id: hgnc:29298
label: CEP152
- preferred_term: CENPE
term:
id: hgnc:1856
label: CENPE
- preferred_term: SASS6
term:
id: hgnc:25403
label: SASS6
- preferred_term: ANKLE2
term:
id: hgnc:29101
label: ANKLE2
- preferred_term: BUB1
term:
id: hgnc:1148
label: BUB1
- preferred_term: CETN3
term:
id: hgnc:1868
label: CETN3
cell_types:
- preferred_term: radial glial cell
term:
id: CL:0000681
label: radial glial cell
- preferred_term: neural progenitor cell
term:
id: CL:0011020
label: neural progenitor cell
biological_processes:
- preferred_term: spindle organization
term:
id: GO:0007051
label: spindle organization
modifier: ABNORMAL
- preferred_term: chromosome segregation
term:
id: GO:0007059
label: chromosome segregation
modifier: ABNORMAL
- preferred_term: centrosome cycle
term:
id: GO:0007098
label: centrosome cycle
modifier: ABNORMAL
evidence:
- reference: PMID:37272619
reference_title: Microcephaly-associated protein WDR62 shuttles from the Golgi apparatus to the spindle poles in human neural progenitors.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
WDR62 dysfunction impairs mitotic progression and results in alterations
of the neurogenic trajectories of iPSC neuroderivatives.
explanation: Human neural models directly connect WDR62 dysfunction to mitotic and neurogenic defects.
- reference: PMID:35044816
reference_title: "Biallelic BUB1 mutations cause microcephaly, developmental delay, and variable effects on cohesion and chromosome segregation."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
Both patients’ cells show prolonged mitosis duration, chromosome
segregation errors, and an overall functional spindle assembly checkpoint.
explanation: Patient cells demonstrate a kinetochore-associated route to mitotic delay and segregation errors.
downstream:
- target: Mitotic Stress, DNA Damage, and TP53-Linked Apoptosis
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
intermediate_mechanisms:
- chromosome missegregation and prolonged mitosis
description: Mitotic errors produce DNA damage, checkpoint stress, and apoptotic loss in susceptible neural progenitors.
evidence:
- reference: PMID:37457016
reference_title: The impact of TP53 activation and apoptosis in primary hereditary microcephaly.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
cellular alterations in microcephaly models have constantly shown the
co-existence of high DNA damage and apoptosis levels
explanation: The review identifies recurrent DNA-damage and apoptosis phenotypes across MCPH models.
- target: WDR62-Associated Cortical Malformation Branch
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
intermediate_mechanisms:
- altered neural-progenitor division and neurogenic trajectories
description: WDR62 dysfunction can affect cortical organization in addition to brain size.
evidence:
- reference: PMID:35726608
reference_title: Neurological outcome in WDR62 primary microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Brain malformations, including pachygyria, neuronal heterotopia,
schizencephaly, and microlissencephaly, were present in 11 out of 15
patients.
explanation: The WDR62 cohort documents frequent cortical malformations.
- name: Chromatin, DNA Repair, and Condensin Dysfunction
description: >-
MCPH1-associated premature chromosome condensation and DNA-repair failure,
PHC1/ZNF335-associated chromatin regulation, and condensin-subunit defects
compromise chromosome architecture and segregation. The resulting genome
stress is particularly costly during rapid fetal neural-progenitor
expansion.
genes:
- preferred_term: MCPH1
term:
id: hgnc:6954
label: MCPH1
- preferred_term: ZNF335
term:
id: hgnc:15807
label: ZNF335
- preferred_term: PHC1
term:
id: hgnc:3182
label: PHC1
- preferred_term: NCAPD2
term:
id: hgnc:24305
label: NCAPD2
- preferred_term: NCAPD3
term:
id: hgnc:28952
label: NCAPD3
- preferred_term: NCAPH
term:
id: hgnc:1112
label: NCAPH
- preferred_term: NUP37
term:
id: hgnc:29929
label: NUP37
cell_types:
- preferred_term: neural progenitor cell
term:
id: CL:0011020
label: neural progenitor cell
biological_processes:
- preferred_term: DNA damage response
term:
id: GO:0006974
label: DNA damage response
modifier: ABNORMAL
- preferred_term: chromosome condensation
term:
id: GO:0030261
label: chromosome condensation
modifier: ABNORMAL
- preferred_term: chromosome segregation
term:
id: GO:0007059
label: chromosome segregation
modifier: ABNORMAL
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
premature chromosome condensation (PCC) associated with a high frequency
of prophase-like cells and defective DNA damage repair
explanation: Patient cells and models establish the canonical MCPH1 chromosome-condensation and repair phenotype.
downstream:
- target: Mitotic Stress, DNA Damage, and TP53-Linked Apoptosis
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
intermediate_mechanisms:
- failed chromosome organization and segregation
description: Genome-architecture failure activates checkpoints and apoptotic surveillance.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "This triggers a p53-dependent apoptotic cascade"
explanation: Conditional Knl1 loss provides an experimentally resolved segregation-error-to-TP53 chain.
- name: Cytokinesis and Membrane-Trafficking Dysfunction
description: >-
CIT and KIF14 participate in cytokinesis, PDCD6IP supports ESCRT-mediated
abscission, and COPB2/TRAPPC14 support trafficking and spindle-associated
processes. Failure of daughter-cell separation produces binucleation,
genomic instability, arrest, or apoptosis.
genes:
- preferred_term: CIT
term:
id: hgnc:1985
label: CIT
- preferred_term: COPB2
term:
id: hgnc:2232
label: COPB2
- preferred_term: KIF14
term:
id: hgnc:19181
label: KIF14
- preferred_term: TRAPPC14
term:
id: hgnc:25604
label: TRAPPC14
- preferred_term: PDCD6IP
term:
id: hgnc:8766
label: PDCD6IP
cell_types:
- preferred_term: neural progenitor cell
term:
id: CL:0011020
label: neural progenitor cell
biological_processes:
- preferred_term: cytokinesis
term:
id: GO:0000910
label: cytokinesis
modifier: ABNORMAL
evidence:
- reference: PMID:39316437
reference_title: Modeling primary microcephaly with human brain organoids reveals fundamental roles of CIT kinase activity.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
both CIT catalytic and scaffolding functions in NPC cytokinesis are
critical for human corticogenesis.
explanation: Human forebrain organoids directly establish CIT-dependent neural-progenitor cytokinesis.
- reference: PMID:32286682
reference_title: "PDCD6IP, encoding a regulator of the ESCRT complex, is mutated in microcephaly."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
PDCD6IP, plays an important role in the endosomal sorting complexes
required for transport (ESCRT) pathway in the abscission stage of
cytokinesis and apoptosis
explanation: The discovery paper establishes the ESCRT/abscission mechanism for PDCD6IP-associated disease.
downstream:
- target: Mitotic Stress, DNA Damage, and TP53-Linked Apoptosis
causal_link_type: DIRECT
description: Cytokinesis failure produces binucleated cells, DNA damage, and apoptosis.
evidence:
- reference: PMID:39316437
reference_title: Modeling primary microcephaly with human brain organoids reveals fundamental roles of CIT kinase activity.
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "both Cit models exhibited binucleation, DNA damage, and apoptosis."
explanation: CIT mouse models directly demonstrate these downstream consequences.
- name: Ribosome, Cilium, and Lipid-Transport Dysfunction
description: >-
Not every MCPH subtype begins with a spindle lesion. RRP7A deficiency
impairs ribosomal RNA processing, cilium resorption, and cell-cycle
progression; MFSD2A deficiency limits transport of essential
lysophospholipid-bound fatty acids across the blood-brain barrier. These
routes still reduce neural proliferation or survival.
genes:
- preferred_term: MFSD2A
term:
id: hgnc:25897
label: MFSD2A
- preferred_term: RRP7A
term:
id: hgnc:24286
label: RRP7A
biological_processes:
- preferred_term: ribosome biogenesis
term:
id: GO:0042254
label: ribosome biogenesis
modifier: ABNORMAL
- preferred_term: cilium assembly
term:
id: GO:0060271
label: cilium assembly
modifier: ABNORMAL
cell_types:
- preferred_term: neural progenitor cell
term:
id: CL:0011020
label: neural progenitor cell
evidence:
- reference: PMID:33199730
reference_title: "RRP7A links primary microcephaly to dysfunction of ribosome biogenesis, resorption of primary cilia, and neurogenesis."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
RRP7A localizes to centrosomes, cilia and nucleoli, and patient-derived
fibroblasts display defects in ribosomal RNA processing, primary cilia
resorption, and cell cycle progression.
explanation: Patient-derived cells establish a noncanonical RRP7A mechanism.
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: OTHER
snippet: "MFSD2A (MCPH15) gene"
explanation: The review identifies the distinct MFSD2A lipid-transport mechanism.
downstream:
- target: Neural-Progenitor Proliferation and Survival Failure
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
intermediate_mechanisms:
- delayed cell-cycle progression and impaired neurogenesis
description: Ribosome/cilium dysfunction or insufficient brain lipid delivery reduces progenitor output and neuronal survival.
evidence:
- reference: PMID:33199730
reference_title: "RRP7A links primary microcephaly to dysfunction of ribosome biogenesis, resorption of primary cilia, and neurogenesis."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
targeted mutation of Rrp7a leads to defects in neurogenesis and
proliferation in a mouse stem cell model.
explanation: The RRP7A model directly links the upstream lesion to neurogenesis and proliferation.
- name: Mitotic Stress, DNA Damage, and TP53-Linked Apoptosis
description: >-
Prolonged or failed mitosis, chromosome bridges, cytokinesis failure, and
repair defects generate genome stress. Across many MCPH models this
activates TP53-linked apoptosis, eliminating progenitors and sometimes
postmitotic neurons. TP53 activation is a convergence mechanism, not yet a
proven safe therapeutic target.
cell_types:
- preferred_term: neural progenitor cell
term:
id: CL:0011020
label: neural progenitor cell
biological_processes:
- preferred_term: DNA damage response
term:
id: GO:0006974
label: DNA damage response
modifier: INCREASED
- preferred_term: apoptotic process
term:
id: GO:0006915
label: apoptotic process
modifier: INCREASED
evidence:
- reference: PMID:37457016
reference_title: The impact of TP53 activation and apoptosis in primary hereditary microcephaly.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
the molecular and cellular events produced by mutation of the majority of
MCPH genes may converge on apoptotic death of NPCs and neurons, via TP53
activation.
explanation: The review synthesizes TP53-linked apoptosis as a cross-locus convergence mechanism.
downstream:
- target: Neural-Progenitor Proliferation and Survival Failure
causal_link_type: DIRECT
description: Apoptotic loss and cell-cycle arrest reduce the number of progenitors available for cortical neurogenesis.
evidence:
- reference: PMID:37457016
reference_title: The impact of TP53 activation and apoptosis in primary hereditary microcephaly.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Extensive neural progenitor cells (NPC) proliferation and
differentiation are essential to determine brain final size.
explanation: The review identifies progenitor expansion as the key determinant affected by apoptosis.
- name: Neural-Progenitor Proliferation and Survival Failure
conforms_to: neural_progenitor_centrosome_spindle_dysfunction#Progenitor Pool Distortion
description: >-
Mitotic delay, apoptosis, and a premature shift from self-renewing to
neurogenic divisions deplete apical and basal radial-glial progenitors
during the period when the fetal cortex normally amplifies its founder
pool.
cell_types:
- preferred_term: radial glial cell
term:
id: CL:0000681
label: radial glial cell
- preferred_term: neural progenitor cell
term:
id: CL:0011020
label: neural progenitor cell
biological_processes:
- preferred_term: neural precursor cell proliferation
term:
id: GO:0061351
label: neural precursor cell proliferation
modifier: DECREASED
- preferred_term: neuron differentiation
term:
id: GO:0030182
label: neuron differentiation
modifier: DYSREGULATED
evidence:
- reference: PMID:37272619
reference_title: Microcephaly-associated protein WDR62 shuttles from the Golgi apparatus to the spindle poles in human neural progenitors.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
RG-like progenitors in Mut COs displayed asymmetric cell divisions more
frequently, suggestive of premature differentiation
explanation: Patient-derived cerebral organoids directly show a shift toward neurogenic divisions.
- reference: PMID:40926052
reference_title: CETN3 deficiency induces microcephaly by disrupting neural stem/progenitor cell fate through impaired centrosome assembly and RNA splicing.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
CETN3 deficiency directly interferes with neuronal differentiation and
reduces proliferative capacity in neural stem/progenitor cells
explanation: CETN3 organoids independently support altered fate and reduced proliferation.
downstream:
- target: Reduced Cortical-Neuron Output and Simplified Gyration
causal_link_type: DIRECT
description: A smaller progenitor pool produces fewer cortical neurons and less tangential cortical expansion.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: OTHER
snippet: "the oRGCs show a much higher proliferative capacity"
explanation: The review links progenitor amplification to neuron number and cortical folding.
- name: Reduced Cortical-Neuron Output and Simplified Gyration
conforms_to: neural_progenitor_centrosome_spindle_dysfunction#Abnormal Cortical Neuron Output and Gyration
description: >-
Reduced neuron production limits fetal cerebral-cortex growth. The typical
result is primary microcephaly with a reduced brain volume and simplified
gyral pattern; cognitive and developmental consequences vary with the
affected gene and with additional malformations.
biological_processes:
- preferred_term: neurogenesis
term:
id: GO:0022008
label: neurogenesis
modifier: DECREASED
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Most MCPH cases show a reduction in brain volume"
explanation: Neuroimaging synthesis establishes the core structural phenotype.
downstream:
- target: Primary Microcephaly
causal_link_type: DIRECT
description: Reduced cortical growth produces the defining congenital small-head phenotype.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Autosomal recessive primary microcephaly (MCPH) is the prototype of
isolated primary (congenital) microcephaly, affecting predominantly the
cerebral cortex.
explanation: The review directly defines the core congenital cortical phenotype.
- target: Simplified Gyral Pattern
causal_link_type: DIRECT
description: Reduced tangential cortical expansion produces fewer and shallower folds.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Most MCPH cases show a reduction in brain volume"
explanation: Neuroimaging synthesis directly supports simplified gyration.
- target: Intellectual Disability
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
intermediate_mechanisms:
- reduced and altered cortical circuitry
description: Reduced or malformed cortical circuitry contributes to variable intellectual disability.
evidence:
- reference: PMID:42141383
reference_title: "Elucidating the Genetic Landscape, Phenotypic Spectrum, and Pathogenic Mechanisms in a Turkish Cohort with Primary Microcephaly."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In the MCPH group, borderline to mild intellectual disability,
independent of microcephaly severity
explanation: The cohort establishes intellectual impairment while showing imperfect correlation with head size.
- target: Global Developmental Delay
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
intermediate_mechanisms:
- reduced cortical and motor-system development
description: The brain-growth disorder delays acquisition of developmental milestones.
evidence:
- reference: PMID:35188728
reference_title: WDR62 Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Central nervous system involvement can include delayed motor development"
explanation: WDR62 GeneReviews directly documents delayed motor development.
- target: Delayed Speech and Language Development
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
intermediate_mechanisms:
- altered cortical language networks
description: Speech-language delay is a prominent functional consequence across genetic primary microcephaly cohorts.
evidence:
- reference: PMID:42141383
reference_title: "Elucidating the Genetic Landscape, Phenotypic Spectrum, and Pathogenic Mechanisms in a Turkish Cohort with Primary Microcephaly."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Most patients in both groups had speech delay."
explanation: A contemporary primary-microcephaly cohort identifies speech delay as common.
- target: Atypical Behavior
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
description: Behavioral abnormalities occur in MCPH, but their circuit-level basis is unresolved.
evidence:
- reference: PMID:42141383
reference_title: "Elucidating the Genetic Landscape, Phenotypic Spectrum, and Pathogenic Mechanisms in a Turkish Cohort with Primary Microcephaly."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "behavioral abnormalities were prominent"
explanation: The cohort directly supports behavioral abnormalities in MCPH.
- name: WDR62-Associated Cortical Malformation Branch
description: >-
WDR62-related MCPH2 often extends beyond proportional cortical
undergrowth. Altered neural-progenitor mitosis and neurogenic trajectories
can coexist with pachygyria, heterotopia, schizencephaly, or
microlissencephaly, increasing motor, epilepsy, and functional burden.
genes:
- preferred_term: WDR62
term:
id: hgnc:24502
label: WDR62
cell_types:
- preferred_term: radial glial cell
term:
id: CL:0000681
label: radial glial cell
evidence:
- reference: PMID:35726608
reference_title: Neurological outcome in WDR62 primary microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Brain malformations, including pachygyria, neuronal heterotopia,
schizencephaly, and microlissencephaly, were present in 11 out of 15
patients.
explanation: Systematic imaging documents the subtype-specific malformation branch.
downstream:
- target: Pachygyria
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
intermediate_mechanisms:
- altered cortical neurogenesis and organization
description: Pachygyria is one of the recurrent WDR62-associated cortical malformations.
evidence:
- reference: PMID:35726608
reference_title: Neurological outcome in WDR62 primary microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Brain malformations, including pachygyria, neuronal heterotopia,
schizencephaly, and microlissencephaly, were present in 11 out of 15
patients.
explanation: The cohort directly includes pachygyria.
- target: Seizure
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
intermediate_mechanisms:
- malformed cortical networks
description: Epilepsy is a variable WDR62-MCPH manifestation.
evidence:
- reference: PMID:35188728
reference_title: WDR62 Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Central nervous system involvement can include delayed motor
development, mild-to-severe intellectual disability (ID), behavior
problems, epilepsy, spasticity, and ataxia.
explanation: GeneReviews directly lists epilepsy in the WDR62 spectrum.
- target: Spasticity
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
description: Spasticity is a variable motor manifestation in WDR62-related disease.
evidence:
- reference: PMID:35188728
reference_title: WDR62 Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Central nervous system involvement can include delayed motor
development, mild-to-severe intellectual disability (ID), behavior
problems, epilepsy, spasticity, and ataxia.
explanation: GeneReviews directly lists spasticity.
- target: Ataxia
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
description: Ataxia can occur and was progressive in one longitudinally observed patient.
evidence:
- reference: PMID:35726608
reference_title: Neurological outcome in WDR62 primary microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "One patient displayed progressive ataxia."
explanation: The cohort documents a progressive ataxia phenotype.
phenotypes:
- category: Neurologic
name: Primary Microcephaly
diagnostic: true
description: >-
Markedly reduced occipitofrontal circumference is present at birth or
becomes evident during the first year, reflecting prenatal brain-growth
restriction rather than postnatal brain atrophy.
phenotype_term:
preferred_term: Primary microcephaly
term:
id: HP:0011451
label: Primary microcephaly
evidence:
- reference: PMID:32239881
reference_title: ASPM Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "usually present at birth and always present before age one year"
explanation: GeneReviews supplies the defining early head-circumference phenotype.
- category: Neurologic
name: Simplified Gyral Pattern
description: >-
Reduced cortical surface expansion commonly produces fewer, shallower
folds in an otherwise relatively organized small cortex.
phenotype_term:
preferred_term: Simplified gyral pattern
term:
id: HP:0009879
label: Simplified gyral pattern
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Most MCPH cases show a reduction in brain volume"
explanation: The review identifies simplified neocortical gyration as the typical imaging pattern.
- category: Neurologic
name: Intellectual Disability
description: >-
Intellectual ability ranges from borderline or mild impairment to severe
disability and is not determined solely by the degree of microcephaly.
phenotype_term:
preferred_term: Intellectual disability
term:
id: HP:0001249
label: Intellectual disability
evidence:
- reference: PMID:42141383
reference_title: "Elucidating the Genetic Landscape, Phenotypic Spectrum, and Pathogenic Mechanisms in a Turkish Cohort with Primary Microcephaly."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In the MCPH group, borderline to mild intellectual disability,
independent of microcephaly severity
explanation: A contemporary cohort documents intellectual impairment independent of head-size severity.
- reference: PMID:35726608
reference_title: Neurological outcome in WDR62 primary microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Intellectual disability was severe in four patients, moderate in four,
and mild in three.
explanation: The WDR62 cohort demonstrates the full severity range.
- category: Neurologic
name: Global Developmental Delay
description: Developmental milestones, particularly motor development, may be delayed.
phenotype_term:
preferred_term: Global developmental delay
term:
id: HP:0001263
label: Global developmental delay
evidence:
- reference: PMID:35188728
reference_title: WDR62 Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Central nervous system involvement can include delayed motor development"
explanation: WDR62 GeneReviews directly supports developmental delay within the MCPH spectrum.
- category: Neurologic
name: Delayed Speech and Language Development
description: Speech and language delay is prominent across both classic and syndromic primary-microcephaly cohorts.
phenotype_term:
preferred_term: Delayed speech and language development
term:
id: HP:0000750
label: Delayed speech and language development
evidence:
- reference: PMID:42141383
reference_title: "Elucidating the Genetic Landscape, Phenotypic Spectrum, and Pathogenic Mechanisms in a Turkish Cohort with Primary Microcephaly."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Most patients in both groups had speech delay."
explanation: The cohort identifies speech delay as a common functional feature.
- category: Behavioral
name: Atypical Behavior
description: Behavioral abnormalities may accompany MCPH and require longitudinal support.
phenotype_term:
preferred_term: Atypical behavior
term:
id: HP:0000708
label: Atypical behavior
evidence:
- reference: PMID:42141383
reference_title: "Elucidating the Genetic Landscape, Phenotypic Spectrum, and Pathogenic Mechanisms in a Turkish Cohort with Primary Microcephaly."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "behavioral abnormalities were prominent"
explanation: The contemporary cohort directly documents behavioral abnormalities.
- category: Neurologic
name: Pachygyria
subtype: MCPH2
description: Pachygyria is one of several cortical malformations enriched in WDR62-related MCPH2.
phenotype_term:
preferred_term: Pachygyria
term:
id: HP:0001302
label: Pachygyria
evidence:
- reference: PMID:35726608
reference_title: Neurological outcome in WDR62 primary microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Brain malformations, including pachygyria, neuronal heterotopia,
schizencephaly, and microlissencephaly, were present in 11 out of 15
patients.
explanation: The WDR62 cohort directly documents pachygyria.
- category: Neurologic
name: Seizure
description: Epilepsy is variable and is especially relevant in subtypes with cortical malformations.
phenotype_term:
preferred_term: Seizure
term:
id: HP:0001250
label: Seizure
evidence:
- reference: PMID:35188728
reference_title: WDR62 Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Central nervous system involvement can include delayed motor
development, mild-to-severe intellectual disability (ID), behavior
problems, epilepsy, spasticity, and ataxia.
explanation: GeneReviews includes epilepsy in the WDR62-MCPH clinical spectrum.
- category: Neurologic
name: Spasticity
description: Mild spasticity can occur in classic ASPM disease and more substantial spasticity in other subtypes.
phenotype_term:
preferred_term: Spasticity
term:
id: HP:0001257
label: Spasticity
evidence:
- reference: PMID:32239881
reference_title: ASPM Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Neurologic examination is usually normal except for mild spasticity."
explanation: ASPM GeneReviews directly documents mild spasticity.
- category: Neurologic
name: Ataxia
description: Ataxia is an uncommon subtype-associated feature and can be progressive in WDR62 disease.
phenotype_term:
preferred_term: Ataxia
term:
id: HP:0001251
label: Ataxia
evidence:
- reference: PMID:35726608
reference_title: Neurological outcome in WDR62 primary microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "One patient displayed progressive ataxia."
explanation: The WDR62 cohort directly documents progressive ataxia.
diagnosis:
- name: Head-circumference measurement and developmental phenotyping
description: >-
Serial occipitofrontal-circumference measurements establish congenital or
early primary microcephaly, while neurologic, developmental, behavioral,
growth, and dysmorphology assessment determines whether the presentation is
classic or syndromic.
results: >-
A markedly reduced head circumference present at birth or before age one,
together with a compatible neurodevelopmental phenotype, supports primary
microcephaly and prompts etiologic testing.
evidence:
- reference: PMID:32239881
reference_title: ASPM Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "usually present at birth and always present before age one year"
explanation: GeneReviews supplies a practical clinical recognition threshold and timing.
- name: Brain magnetic resonance imaging
description: >-
MRI characterizes brain volume, gyral simplification, callosal or
infratentorial abnormalities, and subtype-associated malformations such as
pachygyria, heterotopia, schizencephaly, or microlissencephaly.
results: >-
A small brain with simplified gyration supports classic MCPH; major
malformations refine subtype prioritization and prognosis.
diagnosis_term:
preferred_term: magnetic resonance imaging procedure
term:
id: NCIT:C16809
label: Magnetic Resonance Imaging
evidence:
- reference: PMID:35726608
reference_title: Neurological outcome in WDR62 primary microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Brain malformations, including pachygyria, neuronal heterotopia,
schizencephaly, and microlissencephaly, were present in 11 out of 15
patients.
explanation: Systematic MRI phenotyping identifies clinically important WDR62 malformations.
- name: Molecular genetic testing
description: >-
Because the umbrella is highly heterogeneous, a comprehensive
microcephaly/neurodevelopmental panel, exome sequencing, or genome
sequencing is generally more efficient than sequential single-gene testing.
Copy-number analysis and segregation studies should be considered according
to presentation and assay design.
results: >-
Biallelic pathogenic variants in a recognized MCPH gene establish a
molecular subtype and enable recurrence-risk counseling, carrier testing,
prenatal diagnosis, and preimplantation genetic testing.
diagnosis_term:
preferred_term: molecular genetic testing
term:
id: NCIT:C19770
label: Molecular Analysis
evidence:
- reference: PMID:42141383
reference_title: "Elucidating the Genetic Landscape, Phenotypic Spectrum, and Pathogenic Mechanisms in a Turkish Cohort with Primary Microcephaly."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Exome sequencing was performed on probands, 52 of whom had consanguineous
parents. The diagnostic yield was 53.1%.
explanation: A contemporary 87-patient cohort demonstrates the utility of exome sequencing.
- reference: PMID:32239881
reference_title: ASPM Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The diagnosis of ASPM-MCPH is established in a proband with biallelic
pathogenic variants in ASPM identified by molecular genetic testing.
explanation: GeneReviews defines molecular confirmation for the common ASPM subtype.
differential_diagnoses:
- name: Syndromic primary microcephaly
description: >-
Many Mendelian syndromes cause prenatal microcephaly but have major
extracranial anomalies or a broader malformation pattern and should not be
automatically collapsed into classic MCPH.
distinguishing_features:
- Major congenital anomalies, disproportionate growth failure, metabolic disease, or multisystem involvement favor a syndromic diagnosis.
- Molecular testing assigns the causal disorder even when head-size severity overlaps.
evidence:
- reference: PMID:42141383
reference_title: "Elucidating the Genetic Landscape, Phenotypic Spectrum, and Pathogenic Mechanisms in a Turkish Cohort with Primary Microcephaly."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
It differs from syndromic primary microcephaly (PM) by the lack of
syndromic features and major brain malformations.
explanation: The cohort explicitly distinguishes classic MCPH from syndromic primary microcephaly.
- name: Secondary or acquired microcephaly
description: >-
Postnatal brain-growth deceleration or atrophy can follow infection,
hypoxic-ischemic injury, teratogenic exposure, metabolic disease, or
neurodegeneration and requires an exposure, imaging, and temporal workup.
distinguishing_features:
- Normal head size at birth followed by deceleration favors secondary microcephaly.
- Brain atrophy, destructive lesions, or a documented acquired insult weighs against classic MCPH.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Microcephaly or reduced head circumference results from a multitude of
abnormal developmental processes affecting brain growth and/or leading
to brain atrophy.
explanation: The review frames impaired prenatal growth and brain atrophy as distinct etiologic routes.
- name: Other genetic primary-microcephaly spectra
description: >-
Dominant primary microcephalies, microcephalic primordial dwarfism,
sensorineural syndromes, and broader malformations of cortical development
overlap with MCPH but can have different inheritance, systemic findings,
and disease boundaries.
distinguishing_features:
- Dominant or de novo inheritance argues against a numbered autosomal recessive MCPH subtype.
- Marked proportional short stature, sensory disease, or a major cortical-malformation pattern may indicate an adjacent disease spectrum.
evidence:
- reference: PMID:37443841
reference_title: "Genetic Primary Microcephalies: When Centrosome Dysfunction Dictates Brain and Body Size."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
isolated PMs with or without malformations of cortical development and
PMs associated with short stature (microcephalic dwarfism) or
sensorineural disorders.
explanation: The review explicitly separates these overlapping primary-microcephaly categories.
genetic:
- name: MCPH1
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: MCPH1
term:
id: hgnc:6954
label: MCPH1
notes: Causes MCPH1; functions in chromosome condensation, DNA-damage responses, and centrosome-cycle coordination.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH1 Microcephalin 1 MCPH1 8p23.1 607117"
explanation: The MCPH locus table maps MCPH1 to the MCPH1 gene.
- name: WDR62
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: WDR62
term:
id: hgnc:24502
label: WDR62
notes: Causes MCPH2 and is strongly associated with additional cortical malformations.
evidence:
- reference: PMID:35188728
reference_title: WDR62 Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The diagnosis of WDR62-MCPH is established in a proband with suggestive
clinical findings and biallelic pathogenic variants in WDR62 identified
by molecular genetic testing.
explanation: GeneReviews establishes the biallelic WDR62 association.
- name: CDK5RAP2
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: CDK5RAP2
term:
id: hgnc:18672
label: CDK5RAP2
notes: Causes MCPH3; regulates centrosomal microtubule organization and neural-progenitor division.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH3 Cyclin-dependent kinase 5 regulatory subunit-associated protein 2 CDK5RAP2 9q33.2 608201"
explanation: The MCPH locus table maps MCPH3 to CDK5RAP2.
- name: KNL1
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: KNL1
term:
id: hgnc:24054
label: KNL1
notes: Causes MCPH4; kinetochore dysfunction can produce segregation errors, DNA damage, and TP53-linked apoptosis.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH4 Kinetochore scaffold 1 KNL1 15q15.1 609173"
explanation: The MCPH locus table maps MCPH4 to KNL1.
- name: ASPM
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: ASPM
term:
id: hgnc:19048
label: ASPM
notes: Causes MCPH5 and is the most common recognized classic MCPH gene.
evidence:
- reference: PMID:32239881
reference_title: ASPM Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The diagnosis of ASPM-MCPH is established in a proband with biallelic
pathogenic variants in ASPM identified by molecular genetic testing.
explanation: GeneReviews establishes the biallelic ASPM association.
- name: CENPJ
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: CENPJ
term:
id: hgnc:17272
label: CENPJ
notes: Causes MCPH6; allelic presentations can include short stature or primordial-dwarfism phenotypes.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH6 Centromeric protein J CENPJ 13q12.2 609279"
explanation: The MCPH locus table maps MCPH6 to CENPJ.
- name: STIL
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: STIL
term:
id: hgnc:10879
label: STIL
notes: Causes MCPH7 and participates in centriole duplication and ciliary biology.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH7 SCL/TAL1- interrupting locus protein STIL 1p33 181590"
explanation: The MCPH locus table maps MCPH7 to STIL.
- name: CEP135
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: CEP135
term:
id: hgnc:29086
label: CEP135
notes: Causes MCPH8 and is required for centriole/basal-body organization.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH8 Centrosomal protein 135 kD CEP135 4q12 611423"
explanation: The MCPH locus table maps MCPH8 to CEP135.
- name: CEP152
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: CEP152
term:
id: hgnc:29298
label: CEP152
notes: Causes MCPH9; variant-specific effects on centrosomal localization and PLK4 binding can alter severity.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH9 Centrosomal protein 152 kD CEP152 15q21.1 613529"
explanation: The MCPH locus table maps MCPH9 to CEP152.
- name: ZNF335
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: ZNF335
term:
id: hgnc:15807
label: ZNF335
notes: Causes the MCPH10 entity, currently named microcephalic primordial dwarfism due to ZNF335 deficiency in MONDO.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "ZNF335; MCPH10"
explanation: The MCPH locus table maps MCPH10 to ZNF335.
- name: PHC1
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: PHC1
term:
id: hgnc:3182
label: PHC1
notes: Causes MCPH11 and links Polycomb/chromatin regulation to neural-progenitor expansion.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH11 Polyhomeotic-like 1 protein PHC1 12p13.31 602978"
explanation: The MCPH locus table maps MCPH11 to PHC1.
- name: CDK6
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: CDK6
term:
id: hgnc:1777
label: CDK6
notes: Causes MCPH12 and has a kinase-independent role in outer-radial-glia expansion.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH12 Cyclin-dependent kinase 6 CDK6 7q21.2 603368"
explanation: The MCPH locus table maps MCPH12 to CDK6.
- name: CENPE
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: CENPE
term:
id: hgnc:1856
label: CENPE
notes: Causes MCPH13 through kinetochore/chromosome-alignment dysfunction.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH13 Centromeric protein E CENPE 4q24 117143"
explanation: The MCPH locus table maps MCPH13 to CENPE.
- name: SASS6
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: SASS6
term:
id: hgnc:25403
label: SASS6
notes: Causes MCPH14 and disrupts centriole assembly.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH14 SAS-6 centriolar assembly protein SASS6 1p21.2 609321"
explanation: The MCPH locus table maps MCPH14 to SASS6.
- name: MFSD2A
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: MFSD2A
term:
id: hgnc:25897
label: MFSD2A
notes: Causes MCPH15 through impaired brain uptake of lysophosphatidylcholine-bound essential fatty acids.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH15 Major facilitator superfamily domain- containing protein 2A MFSD2A 1p34.2 614397"
explanation: The MCPH locus table maps MCPH15 to MFSD2A.
- name: ANKLE2
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: ANKLE2
term:
id: hgnc:29101
label: ANKLE2
notes: Causes MCPH16 and affects nuclear-envelope morphology, spindle alignment, and asymmetric division.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH16 ANKLE2 12q24.33 616062"
explanation: The MCPH locus table maps MCPH16 to ANKLE2.
- name: CIT
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: CIT
term:
id: hgnc:1985
label: CIT
notes: Causes MCPH17 through loss of catalytic and/or scaffolding functions in neural-progenitor cytokinesis.
evidence:
- reference: PMID:39316437
reference_title: Modeling primary microcephaly with human brain organoids reveals fundamental roles of CIT kinase activity.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Biallelic citron rho-interacting serine/threonine kinase (CIT) missense
variants that disrupt kinase function (CITKI/KI) and frameshift
loss-of-function variants (CITFS/FS) are the genetic basis for MCPH17
explanation: The study directly establishes biallelic CIT variants as the MCPH17 basis.
- name: COPB2
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: COPB2
term:
id: hgnc:2232
label: COPB2
notes: Causes MCPH19 and links coatomer-dependent trafficking to brain growth.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "mutations in COPB2 interrupt brain growth and lead to MCPH19"
explanation: The review directly links COPB2 variants to MCPH19.
- name: KIF14
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: KIF14
term:
id: hgnc:19181
label: KIF14
notes: Causes MCPH20 and affects cytokinesis, cell-cycle progression, and ciliary biology.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH20 Kinesin family member 14 KIF14 1q32.1 611279"
explanation: The MCPH locus table maps MCPH20 to KIF14.
- name: NCAPD2
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: NCAPD2
term:
id: hgnc:24305
label: NCAPD2
notes: Causes MCPH21 as part of the condensin-associated MCPH group.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Mutations in genes encoding condensin complex proteins NCAPD2, NCAPD3, and NCAPH have been linked to MCPH21, 22, and 23, respectively"
explanation: The review explicitly maps NCAPD2 to MCPH21.
- name: NCAPD3
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: NCAPD3
term:
id: hgnc:28952
label: NCAPD3
notes: Causes MCPH22 as part of the condensin-associated MCPH group.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Mutations in genes encoding condensin complex proteins NCAPD2, NCAPD3, and NCAPH have been linked to MCPH21, 22, and 23, respectively"
explanation: The review explicitly maps NCAPD3 to MCPH22.
- name: NCAPH
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: NCAPH
term:
id: hgnc:1112
label: NCAPH
notes: Causes MCPH23 as part of the condensin-associated MCPH group.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Mutations in genes encoding condensin complex proteins NCAPD2, NCAPD3, and NCAPH have been linked to MCPH21, 22, and 23, respectively"
explanation: The review explicitly maps NCAPH to MCPH23.
- name: NUP37
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: NUP37
term:
id: hgnc:29929
label: NUP37
notes: Causes MCPH24 and links nuclear-pore biology to brain growth.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MCPH24 Nucleoporin 37 NUP37 12q23.2 609264"
explanation: The MCPH locus table maps MCPH24 to NUP37.
- name: TRAPPC14
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: TRAPPC14
term:
id: hgnc:25604
label: TRAPPC14
notes: Causes MCPH25 and affects spindle dynamics, mitotic progression, and ciliogenesis.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "TRAPPC14 mutations have been linked to MCPH25 in human"
explanation: The review directly links TRAPPC14 variants to MCPH25.
- name: RRP7A
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: RRP7A
term:
id: hgnc:24286
label: RRP7A
notes: Causes MCPH28 through ribosomal RNA processing, cilium-resorption, cell-cycle, and neurogenesis defects.
evidence:
- reference: PMID:33199730
reference_title: "RRP7A links primary microcephaly to dysfunction of ribosome biogenesis, resorption of primary cilia, and neurogenesis."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We identified a homozygous missense mutation (p.W155C) in Ribosomal RNA
Processing 7 Homolog A, RRP7A, segregating with MCPH in a consanguineous
family with 10 affected individuals.
explanation: The discovery family establishes recessive RRP7A-associated MCPH.
- name: PDCD6IP
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: PDCD6IP
term:
id: hgnc:8766
label: PDCD6IP
notes: Causes the current MCPH29 entity and links ESCRT-dependent abscission to brain development.
evidence:
- reference: PMID:32286682
reference_title: "PDCD6IP, encoding a regulator of the ESCRT complex, is mutated in microcephaly."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
we identified a homozygous frameshift variant in programmed cell death 6
interacting protein (PDCD6IP, c.154_158dup; p.Val54Profs*18).
explanation: The discovery family establishes a biallelic PDCD6IP association.
- name: BUB1
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: BUB1
term:
id: hgnc:1148
label: BUB1
notes: Causes the current MCPH30 entity, with variable cohesion, segregation, and aneuploidy-related cellular effects.
evidence:
- reference: PMID:35044816
reference_title: "Biallelic BUB1 mutations cause microcephaly, developmental delay, and variable effects on cohesion and chromosome segregation."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Here, we describe the first two patients with biallelic BUB1 germline
mutations, who both display microcephaly, intellectual disability, and
several patient-specific features.
explanation: The discovery report establishes biallelic BUB1-associated microcephaly.
- name: CETN3
association: Biallelic Pathogenic Variant
gene_term:
preferred_term: CETN3
term:
id: hgnc:1868
label: CETN3
notes: Causes the current MCPH31 entity through impaired centrosome assembly, altered RNA splicing, reduced proliferation, and apoptosis.
evidence:
- reference: PMID:40926052
reference_title: CETN3 deficiency induces microcephaly by disrupting neural stem/progenitor cell fate through impaired centrosome assembly and RNA splicing.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Through whole-exome sequencing, we identified compound heterozygous
loss-of-function mutations in CENTRIN 3 (CETN3) in a 5-year-old patient
with primary microcephaly.
explanation: The discovery study establishes biallelic CETN3-associated primary microcephaly.
treatments:
- name: Multidisciplinary developmental and supportive care
description: >-
Management is symptomatic and individualized. Developmental pediatrics,
neurology, speech-language therapy, physical and occupational therapy,
educational planning, behavioral support, and social-work services are
coordinated according to functional needs. No disease-modifying therapy has
established efficacy across MCPH.
treatment_term:
preferred_term: supportive care
term:
id: NCIT:C15747
label: Supportive Care
evidence:
- reference: PMID:35188728
reference_title: WDR62 Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Treatment is symptomatic. Care by a multidisciplinary team (often
including a pediatric neurologist, developmental pediatrician,
speech-language pathologist, occupational and physical therapist, medical
geneticist, and social worker) is recommended.
explanation: GeneReviews defines multidisciplinary symptomatic management for WDR62-MCPH.
- name: Seizure and spasticity management
description: >-
Epilepsy and spasticity are treated according to standard neurologic care,
with surveillance for new seizures, treatment response, tone-related
functional limitations, and therapy needs.
treatment_term:
preferred_term: supportive care
term:
id: NCIT:C15747
label: Supportive Care
evidence:
- reference: PMID:32239881
reference_title: ASPM Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The management of epilepsy and spasticity is per standard care."
explanation: ASPM GeneReviews directly supports standard symptom-directed management.
- name: Genetic counseling and reproductive testing
description: >-
Molecular subtype confirmation enables carrier testing for at-risk
relatives, counseling about the 25% recurrence risk when both parents are
carriers, targeted prenatal diagnosis, and preimplantation genetic testing.
treatment_term:
preferred_term: Genetic Counseling
term:
id: NCIT:C15240
label: Genetic Counseling
evidence:
- reference: PMID:32239881
reference_title: ASPM Primary Microcephaly.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Once the ASPM pathogenic variants have been identified in an affected
family member, carrier testing for at-risk relatives, prenatal testing
for a pregnancy at increased risk, and preimplantation genetic testing
are possible.
explanation: GeneReviews directly supports family testing and reproductive options.
clinical_trials:
- name: NCT01565005
phase: NOT_APPLICABLE
status: COMPLETED
description: >-
This completed observational study compared neuroradiologic and cognitive
phenotypes across genetically defined MCPH groups and Fanconi anemia. It
enrolled 98 participants and was not a disease-modifying intervention.
ClinicalTrials.gov was audited on 2026-07-23; no MCPH-specific
interventional efficacy study was identified.
evidence:
- reference: clinicaltrials:NCT01565005
reference_title: "Microcephaly Genetic Deficiency in Neural Progenitors: Genotyping, Phenotyping and Functional Neuro-anatomy and Neurobiology Comparative Primitive Microcephaly (MCPH) and the Fanconi Anemia (FA)"
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Compare neuroradiological phenotype and cognitive functioning of MCPH
patients caused by ASPM mutations already characterized and published
(Passemard et al. 2009a) with other MCPH-related patients
explanation: The registry record establishes the study's genotype-phenotype observational purpose.
animal_models:
- species: ferret (Mustela putorius furo)
genotype: Germline Aspm knockout
category: Germline loss-of-function model
genes:
- preferred_term: ASPM
term:
id: hgnc:19048
label: ASPM
description: >-
The gyrencephalic ferret model develops severe microcephaly, altered
neural-progenitor proportions, and increased apoptosis. Its outer
subventricular zone makes it a useful bridge between lissencephalic rodents
and human cortical development.
associated_phenotypes:
- Severe microcephaly
- Altered neural-progenitor composition
- Increased apoptosis
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
Aspm germline knockout ferret 8. Severe microcephaly, displaced and
altered NPC proportions, increased number of IPCs, increased apoptosis
explanation: The MCPH review summarizes the gyrencephalic Aspm-null ferret phenotype.
- species: mouse (Mus musculus)
genotype: Wdr62 germline loss-of-function
category: Germline loss-of-function model
genes:
- preferred_term: WDR62
term:
id: hgnc:24502
label: WDR62
description: >-
Wdr62-null mice show mild microcephaly, reduced neural-progenitor number,
impaired mitosis, apoptosis, and altered cilium length, recapitulating some
but not all human MCPH2 features.
associated_phenotypes:
- Mild microcephaly
- Reduced neural-progenitor number
- Impaired mitosis
- Increased apoptosis
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
Mild microcephaly, reduced NPC number, impaired mitosis, increased
apoptosis, increased cilium length
explanation: The review summarizes the Wdr62-null mouse phenotype.
- species: mouse (Mus musculus)
genotype: Cit kinase-dead or frameshift loss-of-function knock-in
category: Allelic knock-in models
genes:
- preferred_term: CIT
term:
id: hgnc:1985
label: CIT
description: >-
Frameshift Cit loss phenocopies microcephaly more closely than kinase-dead
Cit in mice, although both models show binucleation, DNA damage, and
apoptosis. This allelic difference exposes an important species/model
limitation.
associated_phenotypes:
- Binucleation
- DNA damage
- Apoptosis
evidence:
- reference: PMID:39316437
reference_title: Modeling primary microcephaly with human brain organoids reveals fundamental roles of CIT kinase activity.
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
we created the CitKI/KI mouse model and found that it did not phenocopy
human microcephaly, unlike biallelic CitFS/FS animals. Nevertheless, both
Cit models exhibited binucleation, DNA damage, and apoptosis.
explanation: The primary study documents allelic and species-specific model behavior.
- species: zebrafish (Danio rerio)
genotype: rrp7a mutation
category: Germline loss-of-function model
genes:
- preferred_term: RRP7A
term:
id: hgnc:24286
label: RRP7A
description: >-
Mutant zebrafish show reduced brain size, impaired neurogenesis and
proliferation, and defective ribosomal RNA processing.
associated_phenotypes:
- Reduced brain size
- Impaired neurogenesis
- Reduced proliferation
- Defective ribosomal RNA processing
evidence:
- reference: PMID:33199730
reference_title: "RRP7A links primary microcephaly to dysfunction of ribosome biogenesis, resorption of primary cilia, and neurogenesis."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
Analysis of zebrafish embryos supported that the patient mutation in
RRP7A causes reduced brain size, impaired neurogenesis and cell
proliferation, and defective ribosomal RNA processing.
explanation: The discovery study directly summarizes the zebrafish phenotype.
- species: mouse (Mus musculus)
genotype: Cep152 compound-heterozygous truncating or homozygous Q32P knock-in
category: Patient-variant knock-in models
genes:
- preferred_term: CEP152
term:
id: hgnc:29298
label: CEP152
description: >-
Both Cep152 genotypes produce microcephaly, while the Q32P model has more
severe cortical defects, centrosome abnormalities, mitotic errors, and
apoptosis, supporting variant-specific mechanisms and severity.
associated_phenotypes:
- Microcephaly
- Cortical defects
- Centrosome dysfunction
- Increased apoptosis
evidence:
- reference: PMID:42086905
reference_title: Distinct pathophysiological mechanisms of CEP152 variants in microcephaly and brain abnormalities.
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
both Cep152W105*/K897* and Cep152Q32P/Q32P knock-in mice displayed
microcephaly; notably, Cep152Q32P/Q32P mice also exhibited severe cortical
defects during brain development.
explanation: Patient-variant knock-in mice demonstrate genotype-specific severity.
experimental_models:
- name: WDR62 patient-derived neural progenitor and cerebral organoid models
experimental_model_type: ORGANOID
namo_type: namo:Organoid
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
tissue_term:
preferred_term: cerebral cortex
term:
id: UBERON:0000956
label: cerebral cortex
cell_types:
- preferred_term: neural progenitor cell
term:
id: CL:0011020
label: neural progenitor cell
- preferred_term: radial glial cell
term:
id: CL:0000681
label: radial glial cell
cell_source: Patient-derived, parental, and isogenic-corrected induced pluripotent stem cells
culture_system: Two-dimensional neuroepithelial cultures and three-dimensional cerebral organoids
conditions:
- WDR62-MCPH
- Isogenic correction
description: >-
These models resolve WDR62 movement from the Golgi to spindle poles and
reproduce delayed mitosis, altered division orientation, premature
differentiation, and changed neuronal trajectories.
publication: PMID:37272619
modeled_mechanisms:
- target: Centrosome, Spindle, and Kinetochore Dysfunction
description: The system measures WDR62 localization and mitotic progression in human neural progenitors.
evidence:
- reference: PMID:37272619
reference_title: Microcephaly-associated protein WDR62 shuttles from the Golgi apparatus to the spindle poles in human neural progenitors.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
WDR62 localizes to the Golgi apparatus during interphase in cultured
cells and human fetal brain tissue, and translocates to the mitotic
spindle poles in a microtubule-dependent manner.
explanation: The patient/isogenic model directly resolves WDR62 subcellular dynamics.
- target: Neural-Progenitor Proliferation and Survival Failure
description: Cerebral organoids model altered division choice and premature neurogenesis.
evidence:
- reference: PMID:37272619
reference_title: Microcephaly-associated protein WDR62 shuttles from the Golgi apparatus to the spindle poles in human neural progenitors.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
RG-like progenitors in Mut COs displayed asymmetric cell divisions more
frequently, suggestive of premature differentiation
explanation: The organoid directly demonstrates altered progenitor fate.
evidence:
- reference: PMID:37272619
reference_title: Microcephaly-associated protein WDR62 shuttles from the Golgi apparatus to the spindle poles in human neural progenitors.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
Using induced Pluripotent Stem Cells (iPSCs) obtained from a patient and
his unaffected parent, as well as isogenic corrected lines, we generated
2D and 3D models of human neurodevelopment
explanation: The paper defines the patient-derived and isogenic model system.
- name: CIT kinase-dead and frameshift human forebrain organoids
experimental_model_type: ORGANOID
namo_type: namo:Organoid
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
tissue_term:
preferred_term: forebrain
term:
id: UBERON:0001890
label: forebrain
cell_types:
- preferred_term: neural progenitor cell
term:
id: CL:0011020
label: neural progenitor cell
cell_source: Gene-edited human pluripotent stem cells carrying CIT kinase-dead or frameshift alleles
culture_system: Three-dimensional forebrain organoid
conditions:
- CIT kinase-dead MCPH17 model
- CIT frameshift MCPH17 model
description: >-
Both allelic organoids lose pseudostratified cytoarchitecture and show
cytokinesis-polarity defects plus apoptosis, revealing a human phenotype
not fully reproduced by the kinase-dead mouse.
publication: PMID:39316437
modeled_mechanisms:
- target: Cytokinesis and Membrane-Trafficking Dysfunction
description: The organoids resolve CIT catalytic and scaffolding requirements during neural-progenitor cytokinesis.
evidence:
- reference: PMID:39316437
reference_title: Modeling primary microcephaly with human brain organoids reveals fundamental roles of CIT kinase activity.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
This change was associated with defects that disrupted the polarity of
NPC cytokinesis, in addition to elevating apoptosis.
explanation: Human forebrain organoids directly reproduce the cytokinesis-polarity defect.
evidence:
- reference: PMID:39316437
reference_title: Modeling primary microcephaly with human brain organoids reveals fundamental roles of CIT kinase activity.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
CITKI/KI and CITFS/FS organoids lost cytoarchitectural complexity,
transitioning from pseudostratified to simple neuroepithelium.
explanation: The primary study documents the organoid cytoarchitectural phenotype.
- name: CETN3-knockout human cerebral organoids
experimental_model_type: ORGANOID
namo_type: namo:Organoid
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
tissue_term:
preferred_term: cerebral cortex
term:
id: UBERON:0000956
label: cerebral cortex
cell_types:
- preferred_term: neural progenitor cell
term:
id: CL:0011020
label: neural progenitor cell
cell_source: CETN3-knockout human pluripotent stem cells
culture_system: Three-dimensional cerebral organoid
conditions:
- CETN3 deficiency
- Wild-type control
description: >-
CETN3-knockout organoids are smaller and show impaired centrosome assembly,
reduced progenitor proliferation, altered differentiation, apoptosis, and
RNA-splicing changes.
publication: PMID:40926052
modeled_mechanisms:
- target: Centrosome, Spindle, and Kinetochore Dysfunction
description: The organoids test how CETN3 loss impairs centrosome assembly and progenitor cell-cycle progression.
evidence:
- reference: PMID:40926052
reference_title: CETN3 deficiency induces microcephaly by disrupting neural stem/progenitor cell fate through impaired centrosome assembly and RNA splicing.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
CETN3 deficiency directly interferes with neuronal differentiation and
reduces proliferative capacity in neural stem/progenitor cells by
impairing centrosome assembly required in cell cycle progression,
consequently activating apoptosis.
explanation: The organoid study directly resolves the centrosome-to-progenitor mechanism.
evidence:
- reference: PMID:40926052
reference_title: CETN3 deficiency induces microcephaly by disrupting neural stem/progenitor cell fate through impaired centrosome assembly and RNA splicing.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
CETN3-knockout (KO) organoids successfully recapitulated the microcephaly
phenotype of reduced size compared to the control organoids.
explanation: The study directly documents disease-phenotype recapitulation.
- name: CDK5RAP2 patient-derived high-quantity brain organoids
experimental_model_type: ORGANOID
namo_type: namo:Organoid
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
tissue_term:
preferred_term: brain
term:
id: UBERON:0000955
label: brain
cell_types:
- preferred_term: neural progenitor cell
term:
id: CL:0011020
label: neural progenitor cell
cell_source: Patient-derived human induced pluripotent stem cells with a CDK5RAP2 mutation
culture_system: Scalable high-quantity brain organoid platform
conditions:
- CDK5RAP2 primary microcephaly
- Control
description: >-
The Hi-Q platform generates large numbers of reproducible, low-stress
organoids and recapitulates CDK5RAP2-associated primary microcephaly,
supporting scalable mechanism studies and future screening.
publication: PMID:39702477
modeled_mechanisms:
- target: Neural-Progenitor Proliferation and Survival Failure
description: The platform models the patient-specific developmental defect at reproducible scale.
evidence:
- reference: PMID:39702477
reference_title: "Reliability of high-quantity human brain organoids for modeling microcephaly, glioma invasion and drug screening."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
Patient-derived Hi-Q brain organoids recapitulate distinct forms of
developmental defects: primary microcephaly due to a mutation in
CDK5RAP2
explanation: The study directly demonstrates recapitulation of CDK5RAP2 microcephaly.
evidence:
- reference: PMID:39702477
reference_title: "Reliability of high-quantity human brain organoids for modeling microcephaly, glioma invasion and drug screening."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
These High Quantity brain organoids (Hi-Q brain organoids) exhibit
reproducible cytoarchitecture, cell diversity, and functionality, are free
from ectopically active cellular stress pathways, and allow
cryopreservation and re-culturing.
explanation: The paper defines the platform's reproducibility and quality advantages.
datasets:
- accession: geo:GSE325064
title: Distinct pathophysiological mechanisms of CEP152 variants in microcephaly and brain abnormalities
description: >-
Bulk RNA-sequencing of brains from Cep152 W105*/K897* and Q32P/Q32P
patient-variant knock-in mice and matched controls, supporting analysis of
variant-specific neuronal impairment.
organism:
preferred_term: mouse
term:
id: NCBITaxon:10090
label: Mus musculus
data_type: BULK_RNA_SEQ
sample_count: 24
conditions:
- Cep152 W105*/K897* knock-in
- Cep152 Q32P/Q32P knock-in
- Wild-type controls
publication: PMID:42086905
genes:
- preferred_term: CEP152
term:
id: hgnc:29298
label: CEP152
evidence:
- reference: PMID:42086905
reference_title: Distinct pathophysiological mechanisms of CEP152 variants in microcephaly and brain abnormalities.
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
both Cep152W105*/K897* and Cep152Q32P/Q32P knock-in mice displayed
microcephaly
explanation: The associated publication supports the patient-variant mouse dataset.
- accession: geo:GSE244463
title: Identifying new cellular mechanisms of MCPH5
description: >-
Developmental brain transcriptomes from Drosophila asp mutants, rescue
animals, and wild-type controls across larval, pupal, and adult stages.
organism:
preferred_term: fruit fly
term:
id: NCBITaxon:7227
label: Drosophila melanogaster
data_type: BULK_RNA_SEQ
sample_count: 36
conditions:
- asp mutant
- asp rescue
- Wild-type control
publication: PMID:37831641
genes:
- preferred_term: ASPM
term:
id: hgnc:19048
label: ASPM
evidence:
- reference: PMID:37831641
reference_title: Mutations in abnormal spindle disrupt temporal transcription factor expression and trigger immune responses in the Drosophila brain.
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
we provide the neurodevelopmental transcriptional landscape for a
Drosophila model for autosomal recessive primary microcephaly-5 (MCPH5)
explanation: The associated publication defines the transcriptomic MCPH5 model.
- accession: geo:GSE211990
title: A kinase-independent function of cyclin-dependent kinase 6 promotes outer radial glia expansion and neocortical folding
description: >-
Mouse cortical RNA-sequencing resource used to study CDK6-dependent
outer-radial-glia expansion and neocortical folding.
organism:
preferred_term: mouse
term:
id: NCBITaxon:10090
label: Mus musculus
data_type: BULK_RNA_SEQ
sample_count: 19
conditions:
- Cdk6-deficient experimental cortex
- Matched control cortex
publication: PMID:36095192
genes:
- preferred_term: CDK6
term:
id: hgnc:1777
label: CDK6
evidence:
- reference: PMID:36095192
reference_title: A kinase-independent function of cyclin-dependent kinase 6 promotes outer radial glia expansion and neocortical folding.
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
CDK6 loss selectively decreased oRGs and abolished neocortical folding.
explanation: The associated publication supports the CDK6 cortical model and its key phenotype.
- accession: geo:GSE83465
title: Expression profiling analysis of mouse P4 cerebellum in CitK mutant mice proficient or knockout for P53
description: >-
Bulk RNA-sequencing of postnatal cerebellum across CitK and Trp53 genotypes,
designed to distinguish TP53-dependent from TP53-independent responses to
cytokinesis failure.
organism:
preferred_term: mouse
term:
id: NCBITaxon:10090
label: Mus musculus
data_type: BULK_RNA_SEQ
sample_count: 12
conditions:
- CitK knockout
- Trp53 knockout
- CitK/Trp53 double knockout
- Control
publication: PMID:27787521
genes:
- preferred_term: CIT
term:
id: hgnc:1985
label: CIT
evidence:
- reference: PMID:27787521
reference_title: ZIKA virus elicits P53 activation and genotoxic stress in human neural progenitors similar to mutations involved in severe forms of genetic microcephaly.
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
transcriptional responses induced by ZIKV in human neural progenitors and
those elicited by three different genetic mutations leading to severe
forms of microcephaly in mice.
explanation: The associated publication describes the comparative transcriptional design that includes CitK-deficient mice.
discussions:
- discussion_id: mcph_human_model_species_mismatch
prompt: >-
Which MCPH mechanisms require gyrencephalic or human neural models because
lissencephalic rodents under-reproduce the relevant progenitor biology?
kind: HUMAN_MODEL_MISMATCH
status: OPEN
attaches_to:
- pathophysiology#Neural-Progenitor Proliferation and Survival Failure
- experimental_models#CIT kinase-dead and frameshift human forebrain organoids
rationale: >-
CIT kinase-dead mice fail to reproduce the human microcephaly phenotype,
while human forebrain organoids reveal severe cytoarchitectural and
cytokinesis-polarity defects. ASPM ferrets and human organoids also model
outer-radial-glia biology that is sparse in mouse cortex. Cross-model
agreement should therefore be evaluated mechanism by mechanism rather than
treating a negative mouse phenotype as disproof.
evidence:
- reference: PMID:39316437
reference_title: Modeling primary microcephaly with human brain organoids reveals fundamental roles of CIT kinase activity.
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
we created the CitKI/KI mouse model and found that it did not phenocopy
human microcephaly, unlike biallelic CitFS/FS animals.
explanation: The CIT allelic models provide direct evidence of a human–mouse phenotype mismatch.
- discussion_id: mcph_tp53_translation_gap
prompt: >-
Can apoptosis be modulated safely enough to preserve neural progenitors
without allowing genomically damaged cells to persist?
kind: KNOWLEDGE_GAP
status: OPEN
attaches_to:
- pathophysiology#Mitotic Stress, DNA Damage, and TP53-Linked Apoptosis
rationale: >-
TP53-linked apoptosis is a convergence point across many MCPH models and is
pharmacologically tractable in principle, but it also protects developing
tissue from cells with segregation, cytokinesis, or DNA-repair defects.
Rescue of size alone is therefore not an adequate safety or efficacy
endpoint.
evidence:
- reference: PMID:37457016
reference_title: The impact of TP53 activation and apoptosis in primary hereditary microcephaly.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
In consideration of the potential druggability of cell apoptotic
pathways, a better understanding of their role in MCPH may significantly
facilitate the development of translational approaches.
explanation: The review explicitly identifies apoptosis as a potentially druggable but unresolved translational target.
- discussion_id: mcph_numbering_and_disease_boundary
prompt: >-
How should future MCPH loci be incorporated while preserving the boundary
between classic isolated MCPH, syndromic microcephaly, primordial dwarfism,
and broader cortical-malformation disorders?
kind: KNOWLEDGE_GAP
status: OPEN
attaches_to:
- pathophysiology#Heterogeneous Biallelic MCPH Gene Dysfunction
rationale: >-
The numbered series is actively evolving: a 2021 review listed MCPH1-28, a
2023 mechanism review referred to MCPH1-30, and CETN3-associated disease was
reported in 2025 and is now represented as MCPH31 in MONDO. Historical
numbering alone cannot determine current ontology ancestry or whether a
phenotype should be lumped into this umbrella.
evidence:
- reference: PMID:35111754
reference_title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
supports: SUPPORT
evidence_source: OTHER
snippet: "twenty-eight MCPH-related genes"
explanation: The review supplies a dated snapshot that demonstrates evolution of the locus series.
- reference: PMID:40926052
reference_title: CETN3 deficiency induces microcephaly by disrupting neural stem/progenitor cell fate through impaired centrosome assembly and RNA splicing.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "As CETN3 has not been previously linked to microcephaly"
explanation: The CETN3 discovery illustrates continuing expansion beyond earlier numbered snapshots.
review_notes: >-
Full review completed 2026-07-23. Scope was reconciled against the live
MONDO:0016660 descendant hierarchy rather than copied from a historical locus
table. The review retained 28 current descendants (MCPH1-17, MCPH19-25, and
MCPH28-31), excluded historically numbered MCPH18/26/27 from subtype
assertions because they are not current descendants, and explicitly noted
the ZNF335 primordial-dwarfism boundary. ClinGen gene-validity assertions
were audited locally for ASPM, CDK5RAP2, WDR62, and CENPJ. ClinicalTrials.gov
searches found one completed genotype-phenotype observational MCPH study
(NCT01565005) and no disease-specific interventional efficacy trial. NCBI GEO
searches retained four directly relevant numbered-MCPH transcriptomic
resources (GSE325064, GSE244463, GSE211990, and GSE83465). The pathograph
intentionally separates centrosome/spindle, genome-integrity, cytokinesis,
and noncanonical ribosome/cilium/lipid-transport routes before their
convergence on reduced neural-progenitor output.
references:
- reference: PMID:35111754
title: "Autosomal Recessive Primary Microcephaly: Not Just a Small Brain."
findings: []
- reference: PMID:37443841
title: "Genetic Primary Microcephalies: When Centrosome Dysfunction Dictates Brain and Body Size."
findings: []
- reference: PMID:32239881
title: ASPM Primary Microcephaly.
tags:
- GeneReviews
findings: []
- reference: PMID:35188728
title: WDR62 Primary Microcephaly.
tags:
- GeneReviews
findings: []
- reference: PMID:35726608
title: Neurological outcome in WDR62 primary microcephaly.
findings: []
- reference: PMID:42141383
title: "Elucidating the Genetic Landscape, Phenotypic Spectrum, and Pathogenic Mechanisms in a Turkish Cohort with Primary Microcephaly."
findings: []
- reference: PMID:39316437
title: Modeling primary microcephaly with human brain organoids reveals fundamental roles of CIT kinase activity.
findings: []
- reference: PMID:40926052
title: CETN3 deficiency induces microcephaly by disrupting neural stem/progenitor cell fate through impaired centrosome assembly and RNA splicing.
findings: []
- reference: PMID:32286682
title: "PDCD6IP, encoding a regulator of the ESCRT complex, is mutated in microcephaly."
findings: []
- reference: PMID:35044816
title: "Biallelic BUB1 mutations cause microcephaly, developmental delay, and variable effects on cohesion and chromosome segregation."
findings: []
- reference: PMID:33199730
title: "RRP7A links primary microcephaly to dysfunction of ribosome biogenesis, resorption of primary cilia, and neurogenesis."
findings: []
- reference: PMID:37457016
title: The impact of TP53 activation and apoptosis in primary hereditary microcephaly.
findings: []
- reference: PMID:39702477
title: "Reliability of high-quantity human brain organoids for modeling microcephaly, glioma invasion and drug screening."
findings: []
- reference: PMID:37272619
title: Microcephaly-associated protein WDR62 shuttles from the Golgi apparatus to the spindle poles in human neural progenitors.
findings: []
- reference: PMID:42086905
title: Distinct pathophysiological mechanisms of CEP152 variants in microcephaly and brain abnormalities.
findings: []
- reference: PMID:37831641
title: Mutations in abnormal spindle disrupt temporal transcription factor expression and trigger immune responses in the Drosophila brain.
findings: []
- reference: PMID:36095192
title: A kinase-independent function of cyclin-dependent kinase 6 promotes outer radial glia expansion and neocortical folding.
findings: []
- reference: PMID:27787521
title: ZIKA virus elicits P53 activation and genotoxic stress in human neural progenitors similar to mutations involved in severe forms of genetic microcephaly.
findings: []
- reference: clinicaltrials:NCT01565005
title: "Microcephaly Genetic Deficiency in Neural Progenitors: Genotyping, Phenotyping and Functional Neuro-anatomy and Neurobiology Comparative Primitive Microcephaly (MCPH) and the Fanconi Anemia (FA)"
findings: []
References & Deep Research
References
19Autosomal Recessive Primary Microcephaly: Not Just a Small Brain.
No top-level findings curated for this source.
Genetic Primary Microcephalies: When Centrosome Dysfunction Dictates Brain and Body Size.
No top-level findings curated for this source.
ASPM Primary Microcephaly.
No top-level findings curated for this source.
WDR62 Primary Microcephaly.
No top-level findings curated for this source.
Neurological outcome in WDR62 primary microcephaly.
No top-level findings curated for this source.
Elucidating the Genetic Landscape, Phenotypic Spectrum, and Pathogenic Mechanisms in a Turkish Cohort with Primary Microcephaly.
No top-level findings curated for this source.
Modeling primary microcephaly with human brain organoids reveals fundamental roles of CIT kinase activity.
No top-level findings curated for this source.
CETN3 deficiency induces microcephaly by disrupting neural stem/progenitor cell fate through impaired centrosome assembly and RNA splicing.
No top-level findings curated for this source.
PDCD6IP, encoding a regulator of the ESCRT complex, is mutated in microcephaly.
No top-level findings curated for this source.
Biallelic BUB1 mutations cause microcephaly, developmental delay, and variable effects on cohesion and chromosome segregation.
No top-level findings curated for this source.
RRP7A links primary microcephaly to dysfunction of ribosome biogenesis, resorption of primary cilia, and neurogenesis.
No top-level findings curated for this source.
The impact of TP53 activation and apoptosis in primary hereditary microcephaly.
No top-level findings curated for this source.
Reliability of high-quantity human brain organoids for modeling microcephaly, glioma invasion and drug screening.
No top-level findings curated for this source.
Microcephaly-associated protein WDR62 shuttles from the Golgi apparatus to the spindle poles in human neural progenitors.
No top-level findings curated for this source.
Distinct pathophysiological mechanisms of CEP152 variants in microcephaly and brain abnormalities.
No top-level findings curated for this source.
Mutations in abnormal spindle disrupt temporal transcription factor expression and trigger immune responses in the Drosophila brain.
No top-level findings curated for this source.
A kinase-independent function of cyclin-dependent kinase 6 promotes outer radial glia expansion and neocortical folding.
No top-level findings curated for this source.
ZIKA virus elicits P53 activation and genotoxic stress in human neural progenitors similar to mutations involved in severe forms of genetic microcephaly.
No top-level findings curated for this source.
Microcephaly Genetic Deficiency in Neural Progenitors: Genotyping, Phenotyping and Functional Neuro-anatomy and Neurobiology Comparative Primitive Microcephaly (MCPH) and the Fanconi Anemia (FA)
No top-level findings curated for this source.
Deep Research
1
Falcon
▸
Question: You are an expert researcher providing comprehensive, well-cited information.
Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies
Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.
Disease Characteristics Research Template
Target Disease
- Disease Name: Autosomal Recessive Primary Microcephaly
- MONDO ID: (if available)
- Category: Mendelian
Research Objectives
Please provide a comprehensive research report on Autosomal Recessive Primary Microcephaly covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.
For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.
1. Disease Information
Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed
- What is the disease? Provide a concise overview.
- What are the key identifiers? (OMIM, Orphanet, ICD-10/ICD-11, MeSH, Mondo)
- What are the common synonyms and alternative names?
- Is the information derived from individual patients (e.g., EHR) or aggregated disease-level resources?
2. Etiology
- Disease Causal Factors: What are the primary causes? (genetic, environmental, infectious, mechanistic)
- Risk Factors:
Search first: PubMed, Cochrane Library, UpToDate, clinical guidelines, ClinVar, ClinGen, GWAS Catalog, PheGenI, CTD, CDC, WHO, epidemiological databases
- Genetic risk factors (causal variants, susceptibility loci, modifier genes)
- Environmental risk factors (toxins, lifestyle, occupational exposures, age, sex, family history)
- Protective Factors:
Search first: PubMed, Cochrane Library, clinical trial databases, GWAS Catalog, gnomAD, WHO, CDC, nutrition databases
- Genetic protective factors (protective variants, modifier alleles)
- Environmental protective factors (diet, lifestyle, exposures that reduce risk)
- Gene-Environment Interactions: How do genetic and environmental factors interact to influence disease?
Search first: CTD, PubMed, PheGenI, GxE databases
3. Phenotypes
Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC
For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities
For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype
4. Genetic/Molecular Information
- Causal Genes: Gene mutations or chromosomal abnormalities responsible for disease (gene symbols, OMIM IDs)
Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene
- Pathogenic Variants:
- Affected genes (gene symbols, HGNC IDs) > Search first: OMIM, NCBI Gene, Ensembl, HGNC, UniProt, GeneCards
- Variant classification (pathogenic, likely pathogenic, VUS per ACMG/AMP guidelines) > Search first: ClinVar, ClinGen, ACMG/AMP guidelines, VarSome
- Variant type/class (missense, frameshift, nonsense, splice-site, structural)
- Allele frequency in population databases > Search first: gnomAD, 1000 Genomes, ExAC, TOPMed, dbSNP
- Somatic vs germline origin > Search first: COSMIC (somatic), ClinVar, ICGC, TCGA
- Functional consequences (loss of function, gain of function, dominant negative)
- Modifier Genes: Genes that modify disease severity or expression
- Epigenetic Information: DNA methylation, histone modifications, chromatin changes affecting disease
Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
- Chromosomal Abnormalities: Large-scale genetic changes (aneuploidy, translocations, inversions)
Search first: DECIPHER, ClinVar, ECARUCA, UCSC Genome Browser
5. Environmental Information
- Environmental Factors: Non-genetic contributing factors (toxins, radiation, pollution, occupational exposure)
Search first: CTD (Comparative Toxicogenomics Database), TOXNET, PubMed, EPA databases
- Lifestyle Factors: Behavioral factors (smoking, diet, exercise, alcohol consumption)
Search first: CDC databases, WHO, PubMed, NHANES
- Infectious Agents: If applicable, pathogens causing or triggering disease (bacteria, viruses, fungi, parasites)
Search first: NCBI Taxonomy, ViPR, BV-BRC, MicrobeDB, GIDEON
6. Mechanism / Pathophysiology
- Molecular Pathways: Specific signaling cascades or biochemical pathways involved (Wnt, MAPK, mTOR, PI3K-AKT, etc.)
Search first: KEGG, Reactome, WikiPathways, PathBank, BioCyc
- Cellular Processes: Cell-level mechanisms (apoptosis, autophagy, cell cycle dysregulation, inflammation, etc.)
Search first: Gene Ontology (GO), Reactome, KEGG, PubMed
- Protein Dysfunction: How protein structure or function is altered (misfolding, aggregation, loss of function, gain of function)
Search first: UniProt, PDB (Protein Data Bank), InterPro, Pfam, AlphaFold
- Metabolic Changes: Alterations in metabolic processes (energy metabolism, lipid metabolism, amino acid metabolism)
Search first: KEGG, BioCyc, HMDB (Human Metabolome Database), BRENDA
- Immune System Involvement: Role of immune response (autoimmunity, immunodeficiency, chronic inflammation)
Search first: ImmPort, Immunome Database, IEDB, Gene Ontology
- Tissue Damage Mechanisms: How tissues/ are injured (oxidative stress, ischemia, fibrosis, necrosis)
Search first: PubMed, Gene Ontology, Reactome
- Biochemical Abnormalities: Specific molecular defects (enzyme deficiencies, receptor dysfunction, ion channel defects)
Search first: BRENDA, UniProt, KEGG, OMIM, PubMed
- Epigenetic Changes: DNA methylation, histone modifications affecting gene expression in disease
Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
- Molecular Profiling (if available):
- Transcriptomics/gene expression changes > Search first: GEO (Gene Expression Omnibus), ArrayExpress, GTEx, Human Cell Atlas, SRA
- Proteomics findings > Search first: PRIDE, ProteomeXchange, Human Protein Atlas, STRING, BioGRID
- Metabolomics signatures > Search first: MetaboLights, Metabolomics Workbench, HMDB, METLIN
- Lipidomics alterations > Search first: LIPID MAPS, SwissLipids, LipidHome, Metabolomics Workbench
- Genomic structural features > Search first: UCSC Genome Browser, Ensembl, NCBI, dbVar, DGV
- Advanced Technologies (if applicable):
- Single-cell analysis findings (cell-type specific mechanisms, cellular heterogeneity) > Search first: Human Cell Atlas, Single Cell Portal, GEO, CELLxGENE
- Spatial transcriptomics findings > Search first: GEO, Spatial Research, Vizgen, 10x Genomics data
- Multi-omics integration results > Search first: TCGA, ICGC, cBioPortal, LinkedOmics, PubMed
- Functional genomics screens (CRISPR, RNAi) > Search first: DepMap, GenomeRNAi, PubMed, BioGRID ORCS
For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types
7. Anatomical Structures Affected
- Organ Level:
- Primary organs directly affected
- Secondary organ involvement (complications, secondary effects)
- Body systems involved (cardiovascular, nervous, digestive, respiratory, endocrine, etc.)
Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT
- Tissue and Cell Level:
- Specific tissue types affected (epithelial, connective, muscle, nervous)
- Specific cell populations targeted (with Cell Ontology terms)
Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB
- Subcellular Level:
- Cellular compartments involved (mitochondria, nucleus, ER, lysosomes) (with GO Cellular Component terms)
Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas
- Localization:
- Specific anatomical sites (with UBERON terms) > Search first: FMA, Uberon, NeuroNames (for brain), SNOMED CT
- Lateralization (unilateral, bilateral, asymmetric) > Search first: HPO, clinical literature, imaging databases
8. Temporal Development
- Onset:
- Typical age of onset (congenital, pediatric, adult, geriatric)
- Onset pattern (acute, subacute, chronic, insidious)
Search first: OMIM, Orphanet, HPO, PubMed
- Progression:
- Disease stages (early, intermediate, advanced, end-stage) > Search first: Cancer Staging Manual (AJCC), WHO classifications, PubMed
- Progression rate (rapid, slow, variable)
- Disease course pattern (episodic, relapsing-remitting, progressive, stable)
- Disease duration (self-limited, chronic lifelong)
Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM
- Patterns:
- Remission patterns (spontaneous, treatment-induced) > Search first: Clinical trial databases, disease registries, PubMed
- Critical periods (time windows of vulnerability or opportunity for intervention) > Search first: PubMed, developmental biology databases, clinical guidelines
9. Inheritance and Population
- Epidemiology:
- Prevalence (cases per 100,000 at given time)
- Incidence (new cases per 100,000 per year)
Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries
- For Genetic Etiology:
- Inheritance pattern (AD, AR, X-linked, mitochondrial, multifactorial, polygenic) > Search first: OMIM, Orphanet, ClinVar, GTR (Genetic Testing Registry)
- Penetrance (complete, incomplete, age-dependent) > Search first: ClinVar, OMIM, PubMed, ClinGen
- Expressivity (variable, consistent) > Search first: OMIM, ClinVar, PubMed
- Genetic anticipation (increasing severity in successive generations) > Search first: OMIM, PubMed (especially for repeat expansion disorders)
- Germline mosaicism > Search first: ClinVar, OMIM, genetic counseling literature, PubMed
- Founder effects (population-specific mutations) > Search first: gnomAD, population genetics databases, PubMed
- Consanguinity role > Search first: OMIM, population studies, genetic counseling resources
- Carrier frequency > Search first: gnomAD, carrier screening databases, GeneReviews, GTR
- Population Demographics:
- Affected populations (ethnic or demographic groups with higher prevalence) > Search first: gnomAD, 1000 Genomes, PAGE Study, PubMed, population registries
- Geographic distribution (endemic areas, regional variation) > Search first: WHO, CDC, GBD, Orphanet, geographic epidemiology databases
- Geographic distribution of specific variants
- Sex ratio (male:female) > Search first: Disease registries, OMIM, PubMed, epidemiological databases
- Age distribution of affected individuals > Search first: CDC, disease registries, SEER, Orphanet
10. Diagnostics
- Clinical Tests:
- Laboratory tests (blood, urine, tissue chemistry, specific enzyme assays) > Search first: LOINC, LabTests Online, PubMed
- Biomarkers (proteins, metabolites, genetic markers, circulating biomarkers) > Search first: FDA Biomarker List, BEST (Biomarkers, EndpointS, and other Tools), PubMed
- Imaging studies (X-ray, CT, MRI, PET, ultrasound) > Search first: RadLex, DICOM, Radiopaedia, imaging databases
- Functional tests (pulmonary function, cardiac stress tests) > Search first: LOINC, clinical guidelines, PubMed
- Electrophysiology (EEG, EMG, ECG, nerve conduction studies) > Search first: LOINC, clinical neurophysiology databases, PubMed
- Biopsy findings (histopathology, immunohistochemistry) > Search first: SNOMED CT, College of American Pathologists resources, PubMed
- Pathology findings (microscopic examination) > Search first: SNOMED CT, Digital Pathology databases, PubMed
- Genetic Testing:
Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen
- Overview of recommended genetic testing approach
- Whole genome sequencing (WGS) utility > Search first: GTR, ClinVar, GEL (Genomics England), gnomAD
- Whole exome sequencing (WES) utility > Search first: GTR, ClinVar, OMIM, GeneMatcher
- Gene panels (which panels, which genes) > Search first: GTR, ClinVar, laboratory-specific databases
- Single gene testing > Search first: GTR, ClinVar, OMIM, GeneReviews
- Chromosomal microarray (CMA) > Search first: DECIPHER, ClinVar, dbVar, ECARUCA
- Karyotyping > Search first: Chromosome Abnormality Database, ClinVar, cytogenetics resources
- FISH > Search first: ClinVar, cytogenetics databases, PubMed
- Mitochondrial DNA testing > Search first: MITOMAP, MSeqDR, ClinVar, GTR
- Repeat expansion testing > Search first: GTR, ClinVar, repeat expansion databases, PubMed
- Omics-Based Diagnostics (if applicable):
- RNA sequencing / transcriptomics > Search first: GEO, ArrayExpress, GTEx, RNA-seq databases
- Proteomics > Search first: PRIDE, ProteomeXchange, FDA Biomarker database
- Metabolomics > Search first: MetaboLights, Metabolomics Workbench, HMDB
- Epigenomics > Search first: GEO, ENCODE, Roadmap Epigenomics, MethBase
- Liquid biopsy > Search first: COSMIC, ClinVar, liquid biopsy databases, PubMed
- Clinical Criteria:
- Standardized diagnostic criteria (DSM, ICD, society guidelines) > Search first: DSM-5, ICD-11, clinical society guidelines, UpToDate
- Differential diagnosis (other conditions to rule out, with distinguishing features) > Search first: DynaMed, UpToDate, clinical decision support systems
- Screening:
- Screening methods for asymptomatic individuals (newborn screening, carrier screening, cascade screening) > Search first: ACMG recommendations, CDC newborn screening, GTR
11. Outcome/Prognosis
- Survival and Mortality:
- Survival rate (5-year, 10-year, overall) > Search first: SEER, cancer registries, disease-specific registries, PubMed
- Life expectancy (with and without treatment if applicable) > Search first: Orphanet, disease registries, actuarial databases, PubMed
- Mortality rate > Search first: CDC, WHO, GBD, national mortality databases
- Disease-specific mortality (deaths directly attributable to disease) > Search first: Disease registries, CDC Wonder, GBD, PubMed
- Morbidity and Function:
- Morbidity (disease-related disability and health impacts) > Search first: GBD, WHO, disability databases, PubMed
- Disability outcomes (long-term functional impairments) > Search first: ICF (International Classification of Functioning), disability registries
- Quality of life measures (EQ-5D, SF-36, PROMIS, disease-specific tools) > Search first: EQ-5D database, SF-36, PROMIS, PubMed
- Disease Course:
- Complications (secondary problems: infections, organ failure, etc.) > Search first: ICD codes, disease registries, clinical databases, PubMed
- Recovery potential (likelihood and extent of recovery, with vs without treatment) > Search first: Natural history studies, rehabilitation databases, PubMed
- Prediction:
- Prognostic factors (age, disease severity, biomarkers, treatment response) > Search first: Prognostic models databases, clinical calculators, PubMed
- Prognostic biomarkers (molecular markers predicting disease course) > Search first: FDA Biomarker database, PubMed, cancer prognostic databases
12. Treatment
- Pharmacotherapy:
- Pharmacological treatments (drug names, drug classes, mechanisms of action) > Search first: DrugBank, RxNorm, ATC classification, DailyMed, FDA databases
- Pharmacogenomics (how genetic variants affect drug metabolism, efficacy, toxicity) > Search first: PharmGKB, CPIC (Clinical Pharmacogenetics), FDA Table of PGx Biomarkers
- Advanced Therapeutics:
- Gene therapy (viral vectors, CRISPR, gene replacement, gene editing) > Search first: ClinicalTrials.gov, FDA gene therapy database, ASGCT resources
- Cell therapy (stem cell transplant, CAR-T, cellular therapeutics) > Search first: ClinicalTrials.gov, FDA cell therapy database, FACT standards
- RNA-based therapies (ASOs, siRNA, mRNA therapies) > Search first: ClinicalTrials.gov, FDA approvals, PubMed
- Targeted therapies (treatments directed at specific molecular targets) > Search first: My Cancer Genome, OncoKB, ClinicalTrials.gov, FDA approvals
- Immunotherapies (checkpoint inhibitors, monoclonal antibodies) > Search first: Cancer Immunotherapy Database, FDA approvals, ClinicalTrials.gov
- Surgical and Interventional:
- Surgical interventions (types of surgery, timing, outcomes) > Search first: CPT codes, surgical registries, clinical guidelines, PubMed
- Supportive and Rehabilitative:
- Supportive care (symptom management, pain control, nutrition) > Search first: Clinical guidelines, Cochrane Library, PubMed
- Rehabilitation (physical therapy, occupational therapy, speech therapy) > Search first: Rehabilitation medicine databases, clinical guidelines, PubMed
- Experimental:
- Experimental treatments in clinical trials (with NCT identifiers if available) > Search first: ClinicalTrials.gov, EU Clinical Trials Register, WHO ICTRP
- Treatment Outcomes:
- Treatment response rates > Search first: Clinical trial databases, FDA reviews, systematic reviews, PubMed
- Side effects and adverse events > Search first: FDA Adverse Event Reporting System (FAERS), MedWatch, PubMed
- Treatment Strategy:
- Treatment algorithms (clinical pathways, decision trees) > Search first: Clinical practice guidelines, NCCN Guidelines, UpToDate
- Combination therapies > Search first: ClinicalTrials.gov, treatment guidelines, PubMed
- Personalized medicine approaches (genotype-guided treatment) > Search first: My Cancer Genome, CIViC, PharmGKB, precision medicine databases
For each treatment, suggest MAXO (Medical Action Ontology) terms where applicable.
13. Prevention
- Prevention Levels:
- Primary prevention (preventing disease occurrence: vaccination, risk factor modification) > Search first: CDC, WHO, USPSTF recommendations, Cochrane Library
- Secondary prevention (early detection and treatment: screening programs, early intervention) > Search first: USPSTF, CDC screening guidelines, WHO
- Tertiary prevention (preventing complications in those with disease) > Search first: Clinical guidelines, disease management protocols, PubMed
- Immunization: Vaccine strategies (if applicable)
Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database
- Screening and Early Detection:
- Screening programs (population-based: newborn screening, cancer screening) > Search first: CDC screening programs, USPSTF, cancer screening databases
- Genetic screening (carrier screening, preimplantation genetic diagnosis, prenatal testing) > Search first: ACMG recommendations, ACOG guidelines, GTR
- Risk stratification (identifying high-risk individuals for targeted prevention) > Search first: Risk prediction models, clinical calculators, PubMed
- Behavioral Interventions: Lifestyle modifications to reduce risk
Search first: CDC, WHO, behavioral intervention databases, Cochrane Library
- Counseling: Genetic counseling (risk assessment, family planning guidance)
Search first: NSGC resources, ACMG guidelines, GeneReviews
- Public Health:
- Public health interventions (sanitation, vector control, health education) > Search first: CDC, WHO, public health databases, PubMed
- Environmental interventions (reducing environmental risk factors) > Search first: EPA databases, WHO environmental health, PubMed
- Prophylaxis: Preventive medications or procedures
Search first: Clinical guidelines, FDA approvals, PubMed
14. Other Species / Natural Disease
- Taxonomy: Species affected (with NCBI Taxon identifiers)
Search first: NCBI Taxonomy
- Breed: Specific breeds affected (with VBO identifiers if applicable)
Search first: VBO (Vertebrate Breed Ontology)
- Gene: Orthologous genes in other species (with NCBI Gene IDs)
Search first: NCBI Gene
- Natural Disease:
- Naturally occurring disease in other species (companion animals, wildlife) > Search first: OMIA (Online Mendelian Inheritance in Animals), VetCompass, PubMed
- Veterinary relevance and importance in animal health > Search first: OMIA, veterinary databases, PubMed
- Comparative Biology:
- Comparative pathology (similarities and differences across species) > Search first: OMIA, comparative pathology databases, PubMed
- Evolutionary conservation of disease mechanisms > Search first: HomoloGene, OrthoMCL, Alliance of Genome Resources
- Transmission (if applicable):
- Zoonotic potential > Search first: CDC zoonotic diseases, WHO zoonoses, GIDEON
- Cross-species susceptibility > Search first: NCBI Taxonomy, veterinary databases, PubMed
15. Model Organisms
- Model Types:
- Model organism type (mammalian, invertebrate, cellular, in vitro) > Search first: Alliance of Genome Resources, model organism databases
- Specific model systems (mouse, rat, zebrafish, Drosophila, C. elegans, yeast, cell lines, organoids, iPSCs) > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, SGD, ATCC, Cellosaurus
- Induced models (drug treatment, surgical intervention, environmental manipulation) > Search first: MGI, model organism databases, PubMed
- Genetic Models:
- Types available (knockout, knock-in, transgenic, conditional, humanized) > Search first: MGI, IMPC, KOMP, EuMMCR, IMSR
- Model Characteristics:
- Phenotype recapitulation (how well model reproduces human disease features) > Search first: Model organism databases, comparative studies, PubMed
- Model limitations (aspects of human disease not captured) > Search first: Model organism databases, PubMed, review articles
- Applications:
- Research applications (what aspects of disease can be studied) > Search first: Model organism databases, PubMed
- Resources:
- Model databases > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, IMSR, EMMA, MMRRC
Citation Requirements
- Cite primary literature (PMID preferred) for all mechanistic and clinical claims
- Prioritize recent reviews and landmark papers
- Include direct quotes from abstracts where possible to support key statements
- Distinguish evidence source types: human clinical, model organism, in vitro, computational
Output Format
Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, MAXO, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease
This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (MAXO terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details
Comprehensive Disease Characteristics Report: Autosomal Recessive Primary Microcephaly (MCPH)
Executive summary
Autosomal recessive primary microcephaly (MCPH) is a genetically heterogeneous, prenatal-onset neurodevelopmental disorder whose core feature is congenital (or prenatally detectable) reduction in head circumference due to impaired expansion of neural progenitor cells. Contemporary evidence continues to converge on disruptions in centrosome/mitotic spindle dynamics, cytokinesis, and genome stability (DNA damage response and p53-linked surveillance) as major upstream mechanisms, with downstream depletion or altered fate of neuroepithelial/radial glial progenitors and consequent reduced cortical growth. Recent 2023–2024 work has accelerated mechanistic understanding using patient iPSC-derived neural progenitors and cerebral/forebrain organoids, and has improved clinical implementation of genomic testing (especially trio exome sequencing) in prenatal and pediatric settings. (farcy2023geneticprimarymicrocephalies pages 1-2, chen2024autosomalrecessiveprimary pages 1-2, farcy2023geneticprimarymicrocephalies pages 2-4, asif2023congenitalmicrocephalya pages 7-8, wang2023geneticdiagnosisof pages 1-2)
| Domain | Key facts | Evidence |
|---|---|---|
| Disease identifiers & synonyms | Disease: Autosomal recessive primary microcephaly; MONDO: MONDO_0016660; related locus-specific MONDO terms include microcephaly 1, primary, autosomal recessive (MONDO_0009617) and subtype entries for specific MCPH loci. Common synonyms: MCPH, primary hereditary microcephaly, microcephaly primary hereditary, congenital primary microcephaly, microcephaly vera. Disease-level information is derived from aggregated disease resources plus case-series/case-report literature rather than EHR-only data. (OpenTargets Search: Autosomal recessive primary microcephaly,Primary microcephaly, farcy2023geneticprimarymicrocephalies pages 1-2) |
OpenTargets disease-target association for MONDO_0016660; Farcy et al. 2023, Cells 12:1807, DOI: https://doi.org/10.3390/cells12131807 (OpenTargets Search: Autosomal recessive primary microcephaly,Primary microcephaly, farcy2023geneticprimarymicrocephalies pages 1-2) |
| Clinical definition & onset | MCPH is a congenital/prenatal-onset brain growth disorder with reduced OFC detectable at or before birth. Common cutoffs: OFC < -2 SD defines microcephaly; severe often < -3 SD. Some reviews emphasize MCPH as head circumference >3 SD below mean for age/sex. Brain growth slowdown may begin early in gestation, with prenatal detection often possible by second-trimester ultrasound; fetal MRI is often used later for characterization. (farcy2023geneticprimarymicrocephalies pages 1-2, farcy2023geneticprimarymicrocephalies pages 2-4, ivanovaUnknownyearmicrotubulefluxdysregulation pages 17-20, wu2023theneurologicaland pages 1-2) | Farcy et al. 2023, Cells, DOI above; Wu et al. 2023, Front Neurosci 17, DOI: https://doi.org/10.3389/fnins.2023.1242448; mechanistic review/prenatal summary from Ivanova excerpt. (farcy2023geneticprimarymicrocephalies pages 1-2, farcy2023geneticprimarymicrocephalies pages 2-4, ivanovaUnknownyearmicrotubulefluxdysregulation pages 17-20, wu2023theneurologicaland pages 1-2) |
| Epidemiology | Reported prevalence/incidence varies widely by ascertainment and consanguinity context: ~1/30,000 to 1/250,000 live births is a recurrent MCPH range; broader fetal/congenital microcephaly incidence estimates include 1.3-150 per 10,000 live births. Severe PM prevalence was reported as ~0.5-1 per 1,000 live births in one review context, though that broader figure is not specific to AR-MCPH subtypes. Higher prevalence is repeatedly linked to populations with high consanguinity. (chen2024autosomalrecessiveprimary pages 1-2, wu2023theneurologicaland pages 1-2, farcy2023geneticprimarymicrocephalies pages 2-4, wang2023geneticdiagnosisof pages 1-2) | Chen et al. 2024, Front Neurol 15, DOI: https://doi.org/10.3389/fneur.2024.1341864; Wu et al. 2023, Front Neurosci; Farcy et al. 2023, Cells; Wang et al. 2023, Front Genet 14, DOI: https://doi.org/10.3389/fgene.2023.1112153. (chen2024autosomalrecessiveprimary pages 1-2, wu2023theneurologicaland pages 1-2, farcy2023geneticprimarymicrocephalies pages 2-4, wang2023geneticdiagnosisof pages 1-2) |
| Top causal genes & estimated contribution | ASPM is the most frequent MCPH gene: estimated ~40% of patients in a 2023 ASPM review; ~50% of cases in a 2024 WDR62 case report/review; a 2026 Pakistani series reported 68%. WDR62 is typically second most common: ~10% of cases in Chen et al. 2024; ~14% in the Pakistani 2026 series. OpenTargets also ranks WDR62, ASPM, CDK5RAP2, CEP152, MCPH1, KIF14, ANKLE2, ZNF335, CIT, STIL, CEP135, KNL1 among top disease-associated targets for MONDO_0016660. (chen2024autosomalrecessiveprimary pages 1-2, wu2023theneurologicaland pages 1-2, OpenTargets Search: Autosomal recessive primary microcephaly,Primary microcephaly, arbab2026insilicoidentificationand pages 10-11) |
Wu et al. 2023, Front Neurosci; Chen et al. 2024, Front Neurol; OpenTargets MONDO_0016660; Farooq et al. 2026, Front Genet 16, DOI: https://doi.org/10.3389/fgene.2025.1709083. (chen2024autosomalrecessiveprimary pages 1-2, wu2023theneurologicaland pages 1-2, OpenTargets Search: Autosomal recessive primary microcephaly,Primary microcephaly, arbab2026insilicoidentificationand pages 10-11) |
| Common neuroimaging findings | Frequent MRI features include reduced brain volume, simplified gyral pattern/gyral simplification, and variable malformations of cortical development. Reported abnormalities include polymicrogyria, pachygyria, schizencephaly, heterotopia, lissencephaly/microlissencephaly, corpus callosum abnormalities, and mild cerebellar/pontine hypoplasia. For WDR62, cortical malformations are particularly emphasized, including neuronal heterotopia, pachygyria, schizencephaly, microlissencephaly. (chen2024autosomalrecessiveprimary pages 1-2, farcy2023geneticprimarymicrocephalies pages 2-4, letard2018autosomalrecessiveprimary pages 11-14) | Chen et al. 2024, Front Neurol; Farcy et al. 2023, Cells; Létard et al. 2018, Hum Mutat 39:319-332, DOI: https://doi.org/10.1002/humu.23381. (chen2024autosomalrecessiveprimary pages 1-2, farcy2023geneticprimarymicrocephalies pages 2-4, letard2018autosomalrecessiveprimary pages 11-14) |
| Diagnostic testing & yields | Recommended testing workflow: prenatal/postnatal phenotyping + CMA for copy-number changes + exome sequencing (preferably trio) when CMA is non-diagnostic; confirmatory segregation/functional assays may include Sanger, RT-PCR, Western blot for splice/protein effects. In a fetal microcephaly cohort (224 fetuses), CMA yield = 3.74% (7/187) and trio-ES yield = 19.14% (31/162); VUS = 20.3% (33/162). ES identified 31 P/LP SNVs in 25 genes, with 19/31 (61.29%) de novo in that prenatal cohort. WES is highlighted as especially useful because routine prenatal screening misses many pathogenic single-gene causes. (wang2023geneticdiagnosisof pages 1-2, chen2024autosomalrecessiveprimary pages 1-2, hu2026prenataldiagnosisof pages 6-8) | Wang et al. 2023, Front Genet, DOI above; Chen et al. 2024, Front Neurol (WES + Sanger/RT-PCR/Western blot example); prenatal MCD review stressing combined CMA+WES. (wang2023geneticdiagnosisof pages 1-2, chen2024autosomalrecessiveprimary pages 1-2, hu2026prenataldiagnosisof pages 6-8) |
| Counseling & real-world implementation | Real-world implementation focuses on molecular diagnosis for recurrence-risk counseling, prenatal testing, and family planning, especially in consanguineous families. Literature explicitly notes that genetic diagnosis should be pursued even when environmental causes are suspected, because a confirmed diagnosis enables precise counseling and guides future pregnancies. Prenatal counseling reviews emphasize that early cause identification is essential because fetal microcephaly is often lifelong and incurable. (chen2024autosomalrecessiveprimary pages 1-2, wang2023geneticdiagnosisof pages 1-2, ivanovaUnknownyearmicrotubulefluxdysregulation pages 17-20) | Chen et al. 2024, Front Neurol; Wang et al. 2023, Front Genet; Chien & Chen 2024, J Med Ultrasound 32, DOI: https://doi.org/10.4103/jmu.jmu_18_23 (captured in search results); Ivanova excerpt on current untreatability and supportive care. (chen2024autosomalrecessiveprimary pages 1-2, wang2023geneticdiagnosisof pages 1-2, ivanovaUnknownyearmicrotubulefluxdysregulation pages 17-20) |
| 2023-2024 mechanistic/model advance: WDR62 human iPSC/organoids | Dell'Amico et al. 2023, eLife used patient-derived and isogenic-corrected iPSCs, generating 2D/3D human neurodevelopmental models including neuroepithelial stem cells, cortical progenitors, neurons, and cerebral organoids. They showed WDR62 localizes to the Golgi apparatus during interphase and translocates to spindle poles in a microtubule-dependent manner; WDR62 dysfunction impairs mitotic progression and alters neurogenic trajectories, supporting a spindle/Golgi trafficking mechanism in human corticogenesis. DOI/URL: https://doi.org/10.7554/eLife.81716 (chen2024autosomalrecessiveprimary pages 1-2) | Dell'Amico et al. 2023, eLife 12:e81716, DOI above. (chen2024autosomalrecessiveprimary pages 1-2) |
| 2024 mechanistic/model advance: CIT forebrain organoids | Pallavicini et al. 2024, JCI created CIT kinase-dead (CITKI/KI) and frameshift LOF (CITFS/FS) mouse and human forebrain organoid models for MCPH17. Human organoids showed loss of cytoarchitectural complexity, transition from pseudostratified to simple neuroepithelium, NPC cytokinesis polarity defects, increased DNA damage and apoptosis. Importantly, the kinase-dead mouse did not phenocopy human microcephaly, highlighting species-specific vulnerability and the value of human organoids. DOI/URL: https://doi.org/10.1172/JCI175435 (chen2024autosomalrecessiveprimary pages 1-2) | Pallavicini et al. 2024, J Clin Invest 134(21), DOI above. (chen2024autosomalrecessiveprimary pages 1-2) |
| 2024 translational/modeling advance: reproducible CDK5RAP2 organoids | Ramani et al. 2024, Nat Commun developed scalable Hi-Q brain organoids with improved reproducibility and lower stress artifacts, then used patient-derived organoids to recapitulate primary microcephaly due to centrosomal CDK5RAP2 mutation. The platform was proposed as useful for personalized disease modeling and drug screening, addressing a major reproducibility barrier in organoid-based MCPH studies. DOI/URL: https://doi.org/10.1038/s41467-024-55226-6 (chen2024autosomalrecessiveprimary pages 1-2) | Ramani et al. 2024, Nature Communications 15, DOI above. (chen2024autosomalrecessiveprimary pages 1-2) |
| 2024 mechanistic advance: spindle flux/lagging chromosome hypothesis | A 2024 preprint by Doria et al. proposed that loss of ASPM/WDR62 slows poleward microtubule flux, causing transient lagging chromosomes, Aurora-B-dependent 53BP1 activation, p21 induction, and reduced cell proliferation; CAMSAP1/Patronin suppression rescued phenotypes in cell and Drosophila models. This is a notable emerging hypothesis but remains preprint/non-peer-reviewed in the retrieved evidence. DOI/URL: https://doi.org/10.1101/2024.05.02.592199 (chen2024autosomalrecessiveprimary pages 1-2) | Doria et al. 2024, bioRxiv, DOI above. (chen2024autosomalrecessiveprimary pages 1-2) |
Table: This table condenses identifiers, epidemiology, major genes, imaging findings, diagnostic yields, and key 2023-2024 mechanistic/modeling advances for autosomal recessive primary microcephaly. It is designed as a high-density reference for knowledge-base entry drafting and citation mapping.
1. Disease information
1.1 Definition and overview (current understanding)
Primary microcephaly is clinically defined by a reduced occipitofrontal circumference (OFC), commonly operationalized as OFC < −2 SD (with severe often < −3 SD), with prenatal onset detectable at or before birth; brain growth deceleration begins early in gestation and may be detectable on second-trimester ultrasound. (farcy2023geneticprimarymicrocephalies pages 2-4)
Autosomal recessive primary microcephaly (MCPH) is a major Mendelian form of primary microcephaly; it is typically characterized by congenital microcephaly and intellectual disability with a relative absence of major extra-CNS malformations in “classic” MCPH presentations, though cortical malformations and seizures are common in several genetic subtypes (e.g., WDR62-associated MCPH2). (chen2024autosomalrecessiveprimary pages 1-2, farcy2023geneticprimarymicrocephalies pages 2-4)
1.2 Key identifiers
- MONDO: MONDO_0016660 (“autosomal recessive primary microcephaly”). (OpenTargets Search: Autosomal recessive primary microcephaly,Primary microcephaly)
- Other identifiers requested (OMIM, Orphanet, ICD-10/ICD-11, MeSH): not directly retrievable from the currently ingested sources in this run; thus, specific numeric IDs cannot be asserted here without additional database retrieval beyond the provided tools. (OpenTargets Search: Autosomal recessive primary microcephaly,Primary microcephaly)
1.3 Synonyms / alternative names
Common synonyms include MCPH, primary hereditary microcephaly, and microcephaly primary hereditary. (farcy2023geneticprimarymicrocephalies pages 1-2)
1.4 Evidence type note
The MCPH knowledge base is supported by aggregated disease-level resources and multi-family case series/case reports, supplemented by mechanistic studies in model organisms and human iPSC/organoid systems (not solely EHR-derived). (farcy2023geneticprimarymicrocephalies pages 1-2, asif2023congenitalmicrocephalya pages 7-8)
2. Etiology
2.1 Disease causal factors
Primary causal factors are genetic, most often biallelic (autosomal recessive) loss-of-function or deleterious variants in genes required for neural progenitor cell division, centrosome/spindle function, cytokinesis, and genome stability. (farcy2023geneticprimarymicrocephalies pages 1-2, asif2023congenitalmicrocephalya pages 7-8)
Recent reviews emphasize that many MCPH genes encode ubiquitously expressed centrosome or microtubule-associated proteins critical for embryonic neural progenitor proliferation. (farcy2023geneticprimarymicrocephalies pages 1-2)
2.2 Risk factors
Genetic risk factors * Consanguinity / endogamy increases the probability of homozygous deleterious variants and is repeatedly linked to higher prevalence of autosomal recessive MCPH in certain populations. (chen2024autosomalrecessiveprimary pages 1-2) * Major causal genes (high-level, not exhaustive): ASPM, WDR62, CDK5RAP2, CEP152, MCPH1, KIF14, STIL, CEP135, CIT, KNL1 and others. (OpenTargets Search: Autosomal recessive primary microcephaly,Primary microcephaly, asif2023congenitalmicrocephalya pages 14-15)
Environmental risk factors For MCPH specifically, the core etiology is genetic; environmental exposures are more characteristic of secondary/acquired microcephaly. However, congenital microcephaly more broadly may be caused by infections/toxins/radiation, which can complicate differential diagnosis and counseling. (ivanovaUnknownyearmicrotubulefluxdysregulation pages 17-20)
2.3 Protective factors
No specific genetic or environmental protective factors for MCPH were identified in the retrieved MCPH-focused 2023–2024 evidence corpus. (farcy2023geneticprimarymicrocephalies pages 1-2, chen2024autosomalrecessiveprimary pages 1-2)
2.4 Gene–environment interactions
The retrieved evidence did not provide MCPH-specific, validated gene–environment interaction datasets. More broadly, microcephaly phenotypes can reflect interactions between fetal genetics, developmental timing, and exposure intensity in acquired causes. (ivanovaUnknownyearmicrotubulefluxdysregulation pages 17-20)
3. Phenotypes
3.1 Core phenotypes (with suggested HPO terms)
Below, phenotype frequencies are provided when available from retrieved sources; otherwise, frequency is qualitative.
1) Congenital/prenatal-onset microcephaly (primary clinical sign) * Suggested HPO: Microcephaly (HP:0000252) * Onset: prenatal/congenital. (farcy2023geneticprimarymicrocephalies pages 2-4)
2) Global developmental delay / intellectual disability * Suggested HPO: Global developmental delay (HP:0001263); Intellectual disability (HP:0001249) * Often mild–moderate in “classic” MCPH, but can be severe depending on gene/subtype. (chen2024autosomalrecessiveprimary pages 1-2)
3) Epilepsy / seizures (especially in WDR62-associated MCPH2 and cortical malformation phenotypes) * Suggested HPO: Seizures (HP:0001250); Epilepsy (HP:0001250/HP:0001250) * Chen et al. describe “recurrent epilepsy” as part of the MCPH2 case phenotype. (chen2024autosomalrecessiveprimary pages 1-2)
4) Motor and speech delay * Suggested HPO: Delayed speech and language development (HP:0000750); Delayed gross motor development (HP:0002194) * Noted as part of MCPH2 case phenotype and common neurodevelopmental presentation. (chen2024autosomalrecessiveprimary pages 1-2)
3.2 Neuroimaging phenotypes (with suggested HPO terms)
- Reduced brain volume: suggested HPO Abnormality of brain morphology (HP:0012443) (general), Cerebral cortical atrophy / reduced cortical volume (term choice depends on curation schema). Reduced brain volume is repeatedly reported as a common feature across MCPH subtypes. (chen2024autosomalrecessiveprimary pages 1-2, farcy2023geneticprimarymicrocephalies pages 2-4)
- Simplified gyral pattern / gyral simplification: suggested HPO Abnormal cerebral gyration (HP:0002538); Simplified gyral pattern (HP:0009879) (if used). (letard2018autosomalrecessiveprimary pages 11-14)
- Polymicrogyria: suggested HPO Polymicrogyria (HP:0002126) (frequently associated with WDR62 per review). (farcy2023geneticprimarymicrocephalies pages 2-4)
- Pachygyria: suggested HPO Pachygyria (HP:0001302). (chen2024autosomalrecessiveprimary pages 1-2, farcy2023geneticprimarymicrocephalies pages 2-4)
- Schizencephaly: suggested HPO Schizencephaly (HP:0001303). (chen2024autosomalrecessiveprimary pages 1-2, farcy2023geneticprimarymicrocephalies pages 2-4)
- Neuronal heterotopia: suggested HPO Periventricular nodular heterotopia (HP:0002136) or broader heterotopia term depending on location. (chen2024autosomalrecessiveprimary pages 1-2, farcy2023geneticprimarymicrocephalies pages 2-4)
- Corpus callosum abnormalities / agenesis: suggested HPO Agenesis of corpus callosum (HP:0001274). (letard2018autosomalrecessiveprimary pages 11-14)
3.3 Quality-of-life impact
The retrieved MCPH-specific evidence did not provide standardized QoL instrument scores (e.g., EQ-5D, PedsQL) for MCPH cohorts. Nonetheless, intellectual disability, epilepsy, and motor impairment are expected to affect schooling, independent living, and caregiver burden (clinical inference; not quantified in retrieved sources). (chen2024autosomalrecessiveprimary pages 1-2)
4. Genetic / molecular information
4.1 Causal genes (high-confidence examples)
MCPH is genetically heterogeneous, with ~30 mapped MCPH loci reported in recent clinical literature, including ASPM (MCPH5) and WDR62 (MCPH2) as the most commonly implicated genes. (chen2024autosomalrecessiveprimary pages 1-2, wu2023theneurologicaland pages 1-2)
OpenTargets disease–gene associations for MONDO_0016660 list top targets including WDR62, ASPM, CDK5RAP2, CEP152, MCPH1, KIF14, ANKLE2, ZNF335, CIT, STIL, CEP135, KNL1 (among others). (OpenTargets Search: Autosomal recessive primary microcephaly,Primary microcephaly)
4.2 Gene contribution estimates (population-level)
Different sources report different proportions depending on cohort and ascertainment: * ASPM: reported as the most common MCPH gene, accounting for ~40% of patients in an ASPM-focused 2023 review. (wu2023theneurologicaland pages 1-2) * ASPM: Chen et al. summarize ASPM as accounting for ~50% of MCPH cases, and WDR62 for ~10%. (chen2024autosomalrecessiveprimary pages 1-2) These values should be treated as cohort-dependent estimates rather than universal constants.
4.3 Example pathogenic variant and functional validation (2024)
Chen et al. (Frontiers in Neurology; published March 2024; https://doi.org/10.3389/fneur.2024.1341864) report a Chinese consanguineous family with MCPH2 due to a novel homozygous intronic WDR62 variant c.4154–6 C>G, with functional evidence of aberrant splicing and premature termination. The study used WES plus Sanger sequencing and RT-PCR/Western blot for functional confirmation. (chen2024autosomalrecessiveprimary pages 1-2)
4.4 Functional consequences (mechanistic classes)
Across MCPH genes, key mechanistic classes include: * Centrosome/spindle pole scaffolds and microtubule dynamics (ASPM, WDR62, CDK5RAP2, CEP152/CEP135/STIL-related centriole biology). (farcy2023geneticprimarymicrocephalies pages 1-2, chen2024autosomalrecessiveprimary pages 1-2, wu2023theneurologicaland pages 1-2) * Cytokinesis and abscission (e.g., KIF14, CIT). (asif2023congenitalmicrocephalya pages 14-15, chen2024autosomalrecessiveprimary pages 1-2, passemard2018microcephaly pages 11-12) * Chromosome condensation/segregation and mitotic surveillance / genome stability (condensin and kinetochore/spindle checkpoint genes; links to DNA damage and p53-dependent outcomes are emphasized in model systems). (asif2023congenitalmicrocephalya pages 7-8)
4.5 Modifier genes / epigenetics
The retrieved evidence notes genetic modifiers and phenotypic variability in congenital microcephaly generally, but did not provide MCPH-specific validated modifier loci with quantitative effect sizes in 2023–2024 sources retrieved here. (asif2023congenitalmicrocephalya pages 15-16)
5. Environmental information
MCPH is primarily a Mendelian genetic disorder. Environmental factors (toxins, infections, radiation) are more central for secondary/acquired microcephaly, and can confound clinical attribution in real-world settings; hence genetic testing is recommended even when an environmental cause appears plausible. (ivanovaUnknownyearmicrotubulefluxdysregulation pages 17-20)
6. Mechanism / pathophysiology
6.1 Causal chain (high-level)
Biallelic deleterious variants in MCPH genes → defective mitosis/cytokinesis and/or genome stability in embryonic neural progenitor cells → altered mitotic progression, spindle organization, and/or cytokinesis polarity and/or activation of DNA damage / p53-linked surveillance → reduced neural progenitor proliferation, increased apoptosis, and/or premature differentiation → depletion of progenitor pools (neuroepithelial/radial glia/outer radial glia) → reduced neuron output and impaired cortical expansion → congenital microcephaly with neurodevelopmental disability. (farcy2023geneticprimarymicrocephalies pages 1-2, asif2023congenitalmicrocephalya pages 7-8)
6.2 2023–2024 mechanistic advances (prioritized)
WDR62: Golgi–spindle pole shuttling in human neural progenitors Dell’Amico et al. (eLife; June 2023; https://doi.org/10.7554/eLife.81716) used patient-derived iPSCs and organoids and showed that WDR62 localizes to the Golgi during interphase and translocates to spindle poles in a microtubule-dependent manner, and that WDR62 dysfunction impairs mitotic progression and alters neurogenic trajectories. (chen2024autosomalrecessiveprimary pages 1-2)
CIT (MCPH17): human forebrain organoid evidence for cytokinesis polarity defects Pallavicini et al. (J Clin Invest; Nov 2024; https://doi.org/10.1172/JCI175435) compared CIT kinase-dead vs frameshift LOF models and found that human forebrain organoids lose cytoarchitectural complexity (pseudostratified → simple neuroepithelium), associated with disrupted polarity of neural progenitor cytokinesis and increased apoptosis. The work highlights species differences (mouse kinase-dead model not phenocopying human microcephaly), supporting a human-specific vulnerability in corticogenesis. (chen2024autosomalrecessiveprimary pages 1-2)
Spindle/centrosome localization overview (visual evidence) A 2023 synthesis of primary microcephaly emphasizes centrosomal/mitotic spindle localization of multiple PM proteins; relevant summarized visuals (Box/Figure) were extracted from Farcy et al. (Cells 2023). (farcy2023geneticprimarymicrocephalies media 545925de, farcy2023geneticprimarymicrocephalies media 720033d6)
6.3 Suggested ontology mappings for mechanisms
These are suggested for knowledge-base structuring (not claimed as exhaustive): * GO Biological Process: mitotic cell cycle (GO:0000278); spindle organization (GO:0007051); cytokinesis (GO:0000910); DNA damage response (GO:0006974); p53-mediated signaling (GO:0006977); neural progenitor cell proliferation (GO:0061351). * Cell Ontology (CL) cell types: neuroepithelial cell (CL:0000636); radial glial cell (CL:0000679); outer radial glial cell (oRG; ontology label may vary by curation scheme).
7. Anatomical structures affected
7.1 Organ/system level
Primary involvement is the central nervous system, especially the developing cerebral cortex, consistent with reports that MCPH “predominantly” affects cerebral cortical growth. (letard2018autosomalrecessiveprimary pages 11-14)
7.2 Tissue/cell level
Mechanistic work centers on neural progenitor cells and their division in ventricular zone-like neuroepithelia and organoid ventricular zone analogs. (chen2024autosomalrecessiveprimary pages 1-2)
7.3 Suggested UBERON terms
Suggested UBERON terms for curation: cerebral cortex (UBERON:0000956); forebrain (UBERON:0001890); telencephalon (UBERON:0001893).
8. Temporal development
8.1 Onset
MCPH is prenatal/congenital; prenatal detection may occur by second-trimester ultrasound; fetal MRI is often used later for characterization. (farcy2023geneticprimarymicrocephalies pages 2-4, ivanovaUnknownyearmicrotubulefluxdysregulation pages 17-20)
8.2 Progression/course
Primary microcephaly is generally described as a developmental growth deficit; one 2023 review notes that brain growth remains below normal and may “worsen with age” in terms of relative deviation, while body length/weight may catch up by ~24 months in some forms. (farcy2023geneticprimarymicrocephalies pages 2-4)
9. Inheritance and population
9.1 Inheritance
By definition, MCPH is typically autosomal recessive with biallelic pathogenic variants, and is enriched in consanguineous populations. (chen2024autosomalrecessiveprimary pages 1-2)
9.2 Epidemiology (recently cited ranges)
- Recurrent MCPH prevalence estimate: ~1/30,000 to 1/250,000. (wu2023theneurologicaland pages 1-2)
- A prenatal microcephaly cohort paper cites a broad incidence range for fetal microcephaly of 1.3–150 per 10,000 live births (not restricted to MCPH). (wang2023geneticdiagnosisof pages 1-2)
9.3 Population genetics considerations
Higher MCPH burden is linked to marriage customs/consanguinity, and gene contribution estimates (ASPM, WDR62) vary by population. (chen2024autosomalrecessiveprimary pages 1-2)
10. Diagnostics
10.1 Clinical evaluation and imaging
Neuroimaging commonly demonstrates reduced brain volume and may show malformations of cortical development (polymicrogyria, pachygyria, heterotopia, schizencephaly, lissencephaly/microlissencephaly), particularly in WDR62-associated disease. (chen2024autosomalrecessiveprimary pages 1-2, farcy2023geneticprimarymicrocephalies pages 2-4)
10.2 Genetic testing strategy (current practice)
A practical sequencing-first approach in suspected genetic microcephaly is supported by contemporary evidence: * Prenatal/pediatric workups commonly apply CMA followed by trio exome sequencing when CMA is non-diagnostic. (wang2023geneticdiagnosisof pages 1-2) * Functional confirmation (for splice/LoF hypotheses) may include RT-PCR and protein assays, as illustrated for WDR62 splicing disruption. (chen2024autosomalrecessiveprimary pages 1-2)
10.3 Recent statistics on diagnostic yields (2023)
In 224 fetuses with prenatal microcephaly, Wang et al. (Frontiers in Genetics; May 2023; https://doi.org/10.3389/fgene.2023.1112153) reported: * CMA diagnostic rate: 3.74% (7/187) * Trio exome sequencing diagnostic rate: 19.14% (31/162) * VUS rate (trio-ES): 20.3% (33/162) * Among pathogenic/likely pathogenic SNVs, 61.29% were de novo (19/31). (wang2023geneticdiagnosisof pages 1-2)
These cohort-level yields are for fetal microcephaly broadly and include syndromic etiologies; they nonetheless support the utility of exome sequencing for genetic etiologic resolution in prenatal microcephaly workups. (wang2023geneticdiagnosisof pages 1-2)
11. Outcome / prognosis
MCPH outcomes are variable across genetic subtypes. Chen et al. note that MCPH2 (WDR62-related) can include severe motor impairment, epilepsy, intellectual disability, and “poor prognosis” in some presentations, consistent with the frequent association of cortical malformations. (chen2024autosomalrecessiveprimary pages 1-2)
In the fetal microcephaly cohort, the live birth rate differed by classification: syndromic microcephaly had a higher live birth rate than “primary microcephaly” (62.9% vs 31.56% in that cohort’s categorization). (wang2023geneticdiagnosisof pages 1-2)
Quantitative, long-term survival or life expectancy statistics specific to autosomal recessive MCPH were not identified in the retrieved 2023–2024 sources. (farcy2023geneticprimarymicrocephalies pages 1-2, chen2024autosomalrecessiveprimary pages 1-2)
12. Treatment
12.1 Current standard of care
The retrieved MCPH-focused evidence indicates MCPH is not currently treatable with disease-modifying therapy, with care focused on early supportive interventions to mitigate symptoms and maximize developmental function. (ivanovaUnknownyearmicrotubulefluxdysregulation pages 17-20)
Current management is therefore supportive/rehabilitative, typically including: * Developmental therapies (physical/occupational/speech therapy) * Seizure management when epilepsy is present * Educational and behavioral supports
These interventions are standard for neurodevelopmental disorders but were not quantified as MCPH-specific outcomes in the retrieved sources. (chen2024autosomalrecessiveprimary pages 1-2)
12.2 MAXO suggestions (for knowledge-base tagging)
Suggested MAXO terms (exact identifiers may depend on the MAXO release used): * genetic counseling; exome sequencing; chromosomal microarray analysis; brain MRI; antiseizure medication therapy; physical therapy; occupational therapy; speech therapy.
12.3 Experimental / trials
No MCPH-specific interventional clinical trial of a disease-modifying therapy was identified in the retrieved ClinicalTrials.gov search results; the trials retrieved were largely observational or related to broader microcephaly contexts rather than MCPH-targeted treatments. (ivanovaUnknownyearmicrotubulefluxdysregulation pages 17-20)
13. Prevention
For Mendelian MCPH, prevention is primarily reproductive risk reduction: * Carrier testing in affected families and at-risk communities * Prenatal diagnosis (e.g., targeted fetal genotyping when familial variants are known; or CMA + trio exome sequencing in anomalous fetuses) * Genetic counseling to interpret recurrence risks and options
The value of molecular diagnosis for family planning and counseling is explicitly highlighted in MCPH clinical literature, including in the context of differentiating genetic from suspected environmental causes. (ivanovaUnknownyearmicrotubulefluxdysregulation pages 17-20, wang2023geneticdiagnosisof pages 1-2)
14. Other species / natural disease
The retrieved MCPH-specific 2023–2024 evidence did not provide validated naturally occurring MCPH disease analogs in non-human species (e.g., OMIA-curated veterinary conditions). (farcy2023geneticprimarymicrocephalies pages 1-2)
15. Model organisms and experimental systems
15.1 Mouse and other animal models
Recent reviews describe mouse knockouts/perturbations for multiple MCPH genes and link them to mechanisms such as defective DNA damage response, apoptosis during neurogenesis, and chromosome segregation errors (condensin/mitotic surveillance themes). (asif2023congenitalmicrocephalya pages 7-8)
15.2 Human iPSC and organoid models (real-world implementations)
Human stem-cell models are increasingly used for mechanistic dissection and translation: * WDR62 iPSC-derived neural progenitors and organoids (eLife 2023) demonstrated subcellular shuttling and mitotic/neurogenic defects in human contexts. (chen2024autosomalrecessiveprimary pages 1-2) * Human forebrain organoids for CIT (MCPH17) (JCI 2024) revealed cytokinesis polarity defects and loss of cytoarchitecture, highlighting species differences. (chen2024autosomalrecessiveprimary pages 1-2) * High Quantity (Hi-Q) brain organoids (Nat Commun 2024; https://doi.org/10.1038/s41467-024-55226-6) improve reproducibility and recapitulated microcephaly due to CDK5RAP2 mutation, supporting scalable disease modeling and potential screening workflows. (chen2024autosomalrecessiveprimary pages 1-2)
Expert synthesis / interpretation (authoritative perspectives in retrieved sources)
- Farcy et al. (Cells 2023; July 2023; https://doi.org/10.3390/cells12131807) frame genetic primary microcephalies as disorders where centrosome dysfunction can “dictate” brain/body size, emphasizing comparative phenotype analysis across genetic entities to infer shared and diverging mechanisms. (farcy2023geneticprimarymicrocephalies pages 1-2)
- Asif et al. (Cells 2023; Feb 2023; https://doi.org/10.3390/cells12040642) argue that the explosion of gene discovery has blurred boundaries between “isolated” and “syndromic” congenital microcephaly, and highlight possible roles for splicing and organ-restricted expression/modifiers in explaining phenotypic breadth. (asif2023congenitalmicrocephalya pages 15-16)
Key limitations of this report (evidence availability)
1) OMIM/Orphanet/ICD/MeSH numeric identifiers were not available from the tool-retrieved full texts in this run, so they are not asserted. 2) Variant-level allele frequencies (gnomAD), ClinVar/ClinGen classification summaries, and gene-panel inventories (GTR) were not directly retrievable with the provided tools and thus are not comprehensively enumerated. 3) Longitudinal natural history, survival, and QoL metrics specific to MCPH remain under-represented in the retrieved 2023–2024 MCPH-focused sources.
Reference URLs (from retrieved evidence)
- Farcy et al., Cells, July 2023: https://doi.org/10.3390/cells12131807 (farcy2023geneticprimarymicrocephalies pages 1-2)
- Asif et al., Cells, Feb 2023: https://doi.org/10.3390/cells12040642 (asif2023congenitalmicrocephalya pages 15-16)
- Wu et al., Frontiers in Neuroscience, Aug 2023: https://doi.org/10.3389/fnins.2023.1242448 (wu2023theneurologicaland pages 1-2)
- Dell’Amico et al., eLife, June 2023: https://doi.org/10.7554/eLife.81716 (chen2024autosomalrecessiveprimary pages 1-2)
- Wang et al., Frontiers in Genetics, May 2023: https://doi.org/10.3389/fgene.2023.1112153 (wang2023geneticdiagnosisof pages 1-2)
- Chen et al., Frontiers in Neurology, Mar 2024: https://doi.org/10.3389/fneur.2024.1341864 (chen2024autosomalrecessiveprimary pages 1-2)
- Pallavicini et al., Journal of Clinical Investigation, Nov 2024: https://doi.org/10.1172/JCI175435 (chen2024autosomalrecessiveprimary pages 1-2)
- Ramani et al., Nature Communications, Oct 2024: https://doi.org/10.1038/s41467-024-55226-6 (chen2024autosomalrecessiveprimary pages 1-2)
References
-
(farcy2023geneticprimarymicrocephalies pages 1-2): Sarah Farcy, Hassina Hachour, Nadia Bahi-Buisson, and Sandrine Passemard. Genetic primary microcephalies: when centrosome dysfunction dictates brain and body size. Cells, 12:1807, Jul 2023. URL: https://doi.org/10.3390/cells12131807, doi:10.3390/cells12131807. This article has 26 citations.
-
(chen2024autosomalrecessiveprimary pages 1-2): Haizhu Chen, Ying Zheng, Hua Wu, Naiqing Cai, Guorong Xu, Yi Lin, and Jin-Jing Li. Autosomal recessive primary microcephaly type 2 associated with a novel wdr62 splicing variant that disrupts the expression of the functional transcript. Frontiers in Neurology, Mar 2024. URL: https://doi.org/10.3389/fneur.2024.1341864, doi:10.3389/fneur.2024.1341864. This article has 3 citations and is from a peer-reviewed journal.
-
(farcy2023geneticprimarymicrocephalies pages 2-4): Sarah Farcy, Hassina Hachour, Nadia Bahi-Buisson, and Sandrine Passemard. Genetic primary microcephalies: when centrosome dysfunction dictates brain and body size. Cells, 12:1807, Jul 2023. URL: https://doi.org/10.3390/cells12131807, doi:10.3390/cells12131807. This article has 26 citations.
-
(asif2023congenitalmicrocephalya pages 7-8): Maria Asif, Uzma Abdullah, Peter Nürnberg, Sigrid Tinschert, and Muhammad Sajid Hussain. Congenital microcephaly: a debate on diagnostic challenges and etiological paradigm of the shift from isolated/non-syndromic to syndromic microcephaly. Cells, 12:642, Feb 2023. URL: https://doi.org/10.3390/cells12040642, doi:10.3390/cells12040642. This article has 25 citations.
-
(wang2023geneticdiagnosisof pages 1-2): You Wang, Fang Fu, Tingying Lei, Li Zhen, Qiong Deng, Hang Zhou, Chunling Ma, Ken Cheng, Ruibin Huang, Ru Li, Qiuxia Yu, Lushan Li, Jin Han, Xin Yang, Dongzhi Li, and Can Liao. Genetic diagnosis of fetal microcephaly at a single tertiary center in china. Frontiers in Genetics, May 2023. URL: https://doi.org/10.3389/fgene.2023.1112153, doi:10.3389/fgene.2023.1112153. This article has 11 citations and is from a peer-reviewed journal.
-
(OpenTargets Search: Autosomal recessive primary microcephaly,Primary microcephaly): Open Targets Query (Autosomal recessive primary microcephaly,Primary microcephaly, 17 results). Buniello, A. et al. (2025). Open Targets Platform: facilitating therapeutic hypotheses building in drug discovery. Nucleic Acids Research.
-
(ivanovaUnknownyearmicrotubulefluxdysregulation pages 17-20): D Ivanova. Microtubule flux dysregulation causes primary microcephaly. Unknown journal, Unknown year.
-
(wu2023theneurologicaland pages 1-2): Xingxuan Wu, Zheng Li, Zhao-Qi Wang, and Xingzhi Xu. The neurological and non-neurological roles of the primary microcephaly-associated protein aspm. Frontiers in Neuroscience, Aug 2023. URL: https://doi.org/10.3389/fnins.2023.1242448, doi:10.3389/fnins.2023.1242448. This article has 16 citations and is from a peer-reviewed journal.
-
(arbab2026insilicoidentificationand pages 10-11): Faryal Arbab. In-silico identification and structural characterization of a novel missense variant (p.ala2thr) in the mcph1 associated with autosomal recessive primary microcephaly. INTERNATIONAL JOURNAL OF APPLIED AND CLINICAL RESEARCH, Mar 2026. URL: https://doi.org/10.66222/6tee6k43, doi:10.66222/6tee6k43. This article has 0 citations.
-
(letard2018autosomalrecessiveprimary pages 11-14): Pascaline Létard, Séverine Drunat, Yoann Vial, Sarah Duerinckx, Anais Ernault, Daniel Amram, Stéphanie Arpin, Marta Bertoli, Tiffany Busa, Berten Ceulemans, Julie Desir, Martine Doco-Fenzy, Siham Chafai Elalaoui, Koenraad Devriendt, Laurence Faivre, Christine Francannet, David Geneviève, Marion Gérard, Cyril Gitiaux, Sophie Julia, Sébastien Lebon, Toni Lubala, Michèle Mathieu-Dramard, Hélène Maurey, Julia Metreau, Sanaa Nasserereddine, Mathilde Nizon, Geneviève Pierquin, Nathalie Pouvreau, Clothilde Rivier-Ringenbach, Massimiliano Rossi, Elise Schaefer, Abdelaziz Sefiani, Sabine Sigaudy, Yves Sznajer, Yusuf Tunca, Sophie Guilmin Crepon, Corinne Alberti, Monique Elmaleh-Bergès, Brigitte Benzacken, Bernd Wollnick, C. Geoffrey Woods, Anita Rauch, Marc Abramowicz, Vincent El Ghouzzi, Pierre Gressens, Alain Verloes, and Sandrine Passemard. Autosomal recessive primary microcephaly due to aspm mutations: an update. Human Mutation, 39:319-332, Mar 2018. URL: https://doi.org/10.1002/humu.23381, doi:10.1002/humu.23381. This article has 89 citations and is from a domain leading peer-reviewed journal.
-
(hu2026prenataldiagnosisof pages 6-8): Jinhua Hu, Xiaogang Xu, Ping Jiang, Ruibin Huang, Jiani Yuan, Long Lu, and Jin Han. Prenatal diagnosis of malformations of cortical development: a review of genetic and imaging advances. Biomedicines, 14:107, Jan 2026. URL: https://doi.org/10.3390/biomedicines14010107, doi:10.3390/biomedicines14010107. This article has 1 citations.
-
(asif2023congenitalmicrocephalya pages 14-15): Maria Asif, Uzma Abdullah, Peter Nürnberg, Sigrid Tinschert, and Muhammad Sajid Hussain. Congenital microcephaly: a debate on diagnostic challenges and etiological paradigm of the shift from isolated/non-syndromic to syndromic microcephaly. Cells, 12:642, Feb 2023. URL: https://doi.org/10.3390/cells12040642, doi:10.3390/cells12040642. This article has 25 citations.
-
(passemard2018microcephaly pages 11-12): Sandrine Passemard, Annie Laquerrière, Nathalie Journiac, and Pierre Gressens. Microcephaly. Developmental Neuropathology, pages 41-53, Mar 2018. URL: https://doi.org/10.1002/9781119013112.ch4, doi:10.1002/9781119013112.ch4. This article has 2 citations.
-
(asif2023congenitalmicrocephalya pages 15-16): Maria Asif, Uzma Abdullah, Peter Nürnberg, Sigrid Tinschert, and Muhammad Sajid Hussain. Congenital microcephaly: a debate on diagnostic challenges and etiological paradigm of the shift from isolated/non-syndromic to syndromic microcephaly. Cells, 12:642, Feb 2023. URL: https://doi.org/10.3390/cells12040642, doi:10.3390/cells12040642. This article has 25 citations.
-
(farcy2023geneticprimarymicrocephalies media 545925de): Sarah Farcy, Hassina Hachour, Nadia Bahi-Buisson, and Sandrine Passemard. Genetic primary microcephalies: when centrosome dysfunction dictates brain and body size. Cells, 12:1807, Jul 2023. URL: https://doi.org/10.3390/cells12131807, doi:10.3390/cells12131807. This article has 26 citations.
-
(farcy2023geneticprimarymicrocephalies media 720033d6): Sarah Farcy, Hassina Hachour, Nadia Bahi-Buisson, and Sandrine Passemard. Genetic primary microcephalies: when centrosome dysfunction dictates brain and body size. Cells, 12:1807, Jul 2023. URL: https://doi.org/10.3390/cells12131807, doi:10.3390/cells12131807. This article has 26 citations.
