Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 1

disease
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Also known as megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome type 1megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome caused by mutation in PIK3R2MPPH1PIK3R2 megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome

Summary

Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 1 (MONDO:0011313) is a disease caused by variants in PIK3R2 and AKT3, with 5 cohort genes.

At a glance

  • Causal genes: PIK3R2 (GenCC Definitive), AKT3 (GenCC Strong)
  • Cohort genes: 5
  • ClinVar variants: 46

Clinical features

No curated clinical features (Orphanet) for this disease.

Identifiers

Disease identifiers

FieldValue
Canonical namemegalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 1
Mondo IDMONDO:0011313
MeSHC566381
OMIM603387
UMLSC4012727
MedGen861164
GARD0018077
Is cancer (heuristic)no

Also known as: megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 1 · megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome type 1 · megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome caused by mutation in PIK3R2 · MPPH1 · PIK3R2 megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome

Data availability: 46 ClinVar variants · 6 GenCC gene-disease records · 6 cell lines.

Disease family

Classification path: disease › human disease › disease by body system or component › nervous system disordercentral nervous system disorderbrain disorderhydrocephalusmegalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndromemegalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 1

Related subtypes (2): megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 2, megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 3

Genetics & variants

GWAS landscape

No GWAS associations recorded — common-variant (GWAS) studies don’t cover this disease (typical for Mendelian / rare diseases). See the curated gene cohort and Mendelian overlap below.

Variant details and genetic-evidence tiers

ClinVar germline variants

46 retrieved; paginated sample, class counts are floors:

25 uncertain significance, 6 benign, 4 pathogenic, 4 likely pathogenic, 3 conflicting classifications of pathogenicity, 2 likely benign, 1 benign/likely benign, 1 pathogenic/likely pathogenic

ClinVarVariant (HGVS)GeneClassificationReview
1338376NM_001759.4(CCND2):c.851T>A (p.Val284Glu)CCND2Pathogenic/Likely pathogeniccriteria provided, multiple submitters, no conflicts
143990NM_005027.4(PIK3R2):c.1202T>C (p.Leu401Pro)PIK3R2Pathogenicno assertion criteria provided
280374NM_005027.4(PIK3R2):c.1126A>G (p.Lys376Glu)PIK3R2Pathogeniccriteria provided, multiple submitters, no conflicts
39808NM_005027.4(PIK3R2):c.1117G>A (p.Gly373Arg)PIK3R2Pathogenicreviewed by expert panel
995384NM_005027.4(PIK3R2):c.1153G>A (p.Gly385Arg)PIK3R2Pathogenicno assertion criteria provided
3362503NM_005027.4(PIK3R2):c.598+2T>GLOC130063979Likely pathogeniccriteria provided, single submitter
376165NM_005027.4(PIK3R2):c.1681A>G (p.Asn561Asp)PIK3R2Likely pathogeniccriteria provided, single submitter
625283NM_005027.4(PIK3R2):c.1056C>G (p.Phe352Leu)PIK3R2Likely pathogeniccriteria provided, single submitter
976716NM_005027.4(PIK3R2):c.988T>G (p.Trp330Gly)PIK3R2Likely pathogeniccriteria provided, single submitter
1296705NM_005027.4(PIK3R2):c.1243G>A (p.Ala415Thr)PIK3R2Conflicting classifications of pathogenicitycriteria provided, conflicting classifications
1319057NM_005027.4(PIK3R2):c.1217G>A (p.Arg406His)PIK3R2Conflicting classifications of pathogenicitycriteria provided, conflicting classifications
2664174NM_014795.4(ZEB2):c.1858A>G (p.Ile620Val)ZEB2Conflicting classifications of pathogenicitycriteria provided, conflicting classifications
2425279NC_000019.9:g.(?17927663)(19312528_?)dupARMC6Uncertain significancecriteria provided, single submitter
3046834NM_005027.4(PIK3R2):c.668G>A (p.Arg223His)LOC130063979Uncertain significancecriteria provided, single submitter
1032968NM_005027.4(PIK3R2):c.29G>A (p.Arg10His)PIK3R2Uncertain significancecriteria provided, multiple submitters, no conflicts
1405289NM_005027.4(PIK3R2):c.553C>G (p.Leu185Val)PIK3R2Uncertain significancecriteria provided, multiple submitters, no conflicts
1486430NM_005027.4(PIK3R2):c.2120C>T (p.Ala707Val)PIK3R2Uncertain significancecriteria provided, multiple submitters, no conflicts
1705289NM_005027.4(PIK3R2):c.2063C>T (p.Ser688Leu)PIK3R2Uncertain significancecriteria provided, single submitter
1709855NM_005027.4(PIK3R2):c.496G>C (p.Asp166His)PIK3R2Uncertain significancecriteria provided, single submitter
2434859NM_005027.4(PIK3R2):c.1883A>G (p.Asn628Ser)PIK3R2Uncertain significancecriteria provided, single submitter
2434860NM_005027.4(PIK3R2):c.338A>C (p.Asp113Ala)PIK3R2Uncertain significancecriteria provided, single submitter
2434861NM_005027.4(PIK3R2):c.867G>A (p.Gln289=)PIK3R2Uncertain significancecriteria provided, single submitter
2689753NM_005027.4(PIK3R2):c.259_263del (p.Gly87fs)PIK3R2Uncertain significancecriteria provided, multiple submitters, no conflicts
3065767NM_005027.4(PIK3R2):c.1109+1G>APIK3R2Uncertain significancecriteria provided, single submitter
3583541NM_005027.4(PIK3R2):c.158G>C (p.Ser53Thr)PIK3R2Uncertain significancecriteria provided, multiple submitters, no conflicts
3583542NM_005027.4(PIK3R2):c.1523G>A (p.Arg508His)PIK3R2Uncertain significancecriteria provided, single submitter
3672581NM_005027.4(PIK3R2):c.127G>A (p.Val43Met)PIK3R2Uncertain significancecriteria provided, single submitter
3704055NM_005027.4(PIK3R2):c.1192G>A (p.Val398Ile)PIK3R2Uncertain significancecriteria provided, multiple submitters, no conflicts
3731548NM_005027.4(PIK3R2):c.1360C>T (p.Gln454Ter)PIK3R2Uncertain significancecriteria provided, single submitter
4279773NM_005027.4(PIK3R2):c.2043G>C (p.Glu681Asp)PIK3R2Uncertain significancecriteria provided, single submitter

Genes & proteins

Mendelian disease overlap and somatic drivers

GenCC: 15 · Orphanet: 7 · OMIM-shared: 0 · Dual-evidence (GWAS+Mendelian): 0

GenCC gene–disease validity (cohort genes)

the Disease column is the GenCC-asserted condition — a cohort gene’s strongest validity may be for a related predisposition syndrome.

GeneClassificationInheritanceDiseaseRecords
PIK3R2DefinitiveAutosomal dominantmegalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 17
AKT3StrongAutosomal dominantmegalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 28

Orphanet rare-disease linkage (cohort genes)

GeneOrphanet IDRare disease
PIK3R2Orphanet:83473Megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome
AKT3Orphanet:83473Megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome
AKT3Orphanet:99802Hemimegalencephaly
ZEB2Orphanet:261537Mowat-Wilson syndrome due to monosomy 2q22
ZEB2Orphanet:261552Mowat-Wilson syndrome due to a ZEB2 point mutation
ZEB2Orphanet:626Large/giant congenital melanocytic nevus
CCND2Orphanet:83473Megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome

Cohort genes → proteins

5 cohort genes, 5 distinct canonical proteins.

Evidence partition

SubsetGenes
multi_evidence5

Cohort genes (full)

SymbolHGNCEnsemblUniProtNameEvidence
PIK3R2HGNC:8980ENSG00000105647O00459Phosphatidylinositol 3-kinase regulatory subunit betagencc,clinvar
AKT3HGNC:393ENSG00000117020Q9Y243RAC-gamma serine/threonine-protein kinasegencc
ZEB2HGNC:14881ENSG00000169554O60315Zinc finger E-box-binding homeobox 2clinvar
CCND2HGNC:1583ENSG00000118971P30279G1/S-specific cyclin-D2clinvar
ARMC6HGNC:25049ENSG00000105676Q6NXE6Armadillo repeat-containing protein 6clinvar

Cohort function summary

Lead sentence per gene, UniProt-curated.

SymbolProtein nameFunction (lead sentence)
PIK3R2Phosphatidylinositol 3-kinase regulatory subunit betaRegulatory subunit of phosphoinositide-3-kinase (PI3K), a kinase that phosphorylates PtdIns(4,5)P2 (Phosphatidylinositol 4,5-bisphosphate) to generate phosphatidylinositol 3,4,5-trisphosphate (PIP3).
AKT3RAC-gamma serine/threonine-protein kinaseAKT3 is one of 3 closely related serine/threonine-protein kinases (AKT1, AKT2 and AKT3) called the AKT kinase, and which regulate many processes including metabolism, proliferation, cell survival, growth and angiogenesis.
ZEB2Zinc finger E-box-binding homeobox 2Transcriptional inhibitor that binds to DNA sequence 5’-CACCT-3’ in different promoters.
CCND2G1/S-specific cyclin-D2Regulatory component of the cyclin D2-CDK4 (DC) complex that phosphorylates and inhibits members of the retinoblastoma (RB) protein family including RB1 and regulates the cell-cycle during G(1)/S transition.

Protein-family classification

Druggable: 2 · Difficult: 1 · Unknown: 2 · Druggable fraction: 0.4

Family distribution

Cohort families vs a genome-wide background (hypergeometric, BH-FDR; fold = observed/expected). Counts kept; sorted by enrichment, so the catch-all Other/Unknown bucket no longer leads.

FamilyGenesFoldFDR
Kinase211.1×0.036
Transcription factor11.6×0.713
Other/Unknown20.7×0.877

Per-gene assignment

SymbolFamilyDruggable?ECInterPro (top 3)
PIK3R2Kinaseyes2.7.1.137RhoGAP_dom, SH2, SH3_domain
AKT3Kinaseyes2.7.11.1Prot_kinase_dom, AGC-kinase_C, PH_domain
ZEB2Transcription factornoHD, Di19_Zn-bd, Homeodomain-like_sf
CCND2Other/UnknownnoCyclin_C-dom, Cyclin_N, Cyclin-like_dom
ARMC6Other/UnknownnoArmadillo, ARM-like, ARM-type_fold

Expression context

Cohort genes with no expression data: 0.

5 cohort genes are a single-cell marker in ≥1 SCXA experiment.

Breadth distribution (Bgee present_calls)

BucketGenes
narrow (1-5 tissues)0
moderate (6-20)0
broad (>20)5
unknown0

Top tissues across cohort

TissueCohort genes
cortical plate4
ganglionic eminence1
stromal cell of endometrium1
calcaneal tendon1
embryo1
monocyte1
sural nerve1
adrenal tissue1
cauda epididymis1
seminal vesicle1
primordial germ cell in gonad1
right lobe of liver1

Per-gene tissue summary (top 30)

SymbolBgee breadthFANTOM5 breadthSCXATop tissues
PIK3R2138ubiquitousmarkercortical plate, ganglionic eminence, stromal cell of endometrium
AKT3231ubiquitousmarkercortical plate, calcaneal tendon, embryo
ZEB2290ubiquitousmarkercortical plate, sural nerve, monocyte
CCND2293ubiquitousmarkeradrenal tissue, seminal vesicle, cauda epididymis
ARMC6259ubiquitousmarkerright lobe of liver, cortical plate, primordial germ cell in gonad

Protein interactions among cohort

Intra-cohort edges: 1.

Hub genes (top 10 by interactor count)

SymbolInteractor count
CCND23,569
AKT33,392
ZEB23,193
PIK3R22,751
ARMC61,001

Intra-cohort edges

ABSources
AKT3PIK3R2string_interaction

Structural data

PDB: 4 · AlphaFold-only: 1 · No structure: 0

Cohort genes with PDB structures (top 30)

SymbolUniProtPDB entries
PIK3R2O004598
AKT3Q9Y2432
ZEB2O603151
CCND2P302791

AlphaFold-only cohort genes (top 30 by pLDDT)

SymbolUniProtpLDDT
ARMC6Q6NXE691.10

Function

Pathway analysis

Distinct Reactome pathways touched by cohort: 141. Enrichment computed across 5 evidence-associated genes (4 with Reactome annotation).

Pathways by enrichment

Over-representation of cohort genes vs the genome-wide background (hypergeometric test, Benjamini-Hochberg FDR; fold = observed/expected over 4 annotated cohort genes). Counts and members are kept as ground-truth; sorted by enrichment.

PathwayCohort genesFoldFDRSample cohort genes
CD28 dependent PI3K/Akt signaling2196.9×0.005PIK3R2, AKT3
Mitotic G1 phase and G1/S transition292.1×0.009CCND2, AKT3
Extra-nuclear estrogen signaling285.2×0.009PIK3R2, AKT3
VEGFA-VEGFR2 Pathway269.6×0.011PIK3R2, AKT3
AKT-mediated inactivation of FOXO1A1713.8×0.023AKT3
Inhibition of TSC complex formation by AKT (PKB)1571.0×0.023AKT3
Drug-mediated inhibition of CDK4/CDK6 activity1571.0×0.023CCND2
G-protein beta:gamma signalling1475.8×0.023AKT3
Signaling by LTK in cancer1407.9×0.023PIK3R2
RUNX2 regulates genes involved in cell migration1356.9×0.023AKT3
PI3K/AKT activation1317.2×0.023PIK3R2
AKT phosphorylates targets in the nucleus1285.5×0.023AKT3
Formation of the posterior neural plate1285.5×0.023ZEB2
IRS-mediated signalling1259.6×0.023PIK3R2
Regulation of CDH11 gene transcription1259.6×0.023ZEB2
Formation of the anterior neural plate1259.6×0.023ZEB2
Co-stimulation by ICOS1259.6×0.023PIK3R2
Regulation of localization of FOXO transcription factors1237.9×0.023AKT3
Positive Regulation of CDH1 Gene Transcription1237.9×0.023ZEB2
Aberrant regulation of mitotic G1/S transition in cancer due to RB1 defects1219.6×0.023CCND2
Signaling by PDGFRA transmembrane, juxtamembrane and kinase domain mutants1219.6×0.023PIK3R2
Signaling by PDGFRA extracellular domain mutants1219.6×0.023PIK3R2
SARS-CoV-2 targets host intracellular signalling and regulatory pathways1219.6×0.023AKT3
Signaling by LTK1219.6×0.023PIK3R2
Downregulation of ERBB2:ERBB3 signaling1203.9×0.023AKT3
AKT phosphorylates targets in the cytosol1203.9×0.023AKT3
Regulation of TP53 Activity through Association with Co-factors1203.9×0.023AKT3
PIP3 activates AKT signaling233.4×0.023PIK3R2, AKT3
Cell Cycle, Mitotic224.1×0.023CCND2, AKT3
Cell Cycle218.0×0.023CCND2, AKT3

GO biological processes by enrichment

Over-representation of cohort genes vs the genome-wide background (hypergeometric test, Benjamini-Hochberg FDR; fold = observed/expected over 5 annotated cohort genes). Counts and members are kept as ground-truth; sorted by enrichment.

GO termCohort genesFoldFDRSample cohort genes
mammillary axonal complex development13370.4×0.006ZEB2
positive regulation of myofibroblast contraction13370.4×0.006ZEB2
regulation of blood-brain barrier permeability13370.4×0.006ZEB2
insulin receptor signaling pathway288.7×0.006PIK3R2, AKT3
positive regulation of lens fiber cell differentiation11685.2×0.006ZEB2
regulation of melanosome organization11685.2×0.006ZEB2
regulation of myofibroblast cell apoptotic process11685.2×0.006ZEB2
melanocyte migration11123.5×0.008ZEB2
myofibroblast differentiation1674.1×0.010ZEB2
positive regulation of melanocyte differentiation1674.1×0.010ZEB2
positive regulation of artery morphogenesis1674.1×0.010AKT3
corpus callosum morphogenesis1481.5×0.011ZEB2
corticospinal tract morphogenesis1481.5×0.011ZEB2
fibroblast activation1481.5×0.011ZEB2
developmental pigmentation1421.3×0.011ZEB2
response to oxygen-glucose deprivation1421.3×0.011ZEB2
cellular response to X-ray1337.0×0.013CCND2
negative regulation of fibroblast migration1306.4×0.013ZEB2
positive regulation of melanin biosynthetic process1280.9×0.013ZEB2
negative regulation of PERK-mediated unfolded protein response1280.9×0.013AKT3
cell proliferation in forebrain1259.3×0.013ZEB2
positive regulation of cell size1259.3×0.013AKT3
collateral sprouting1240.7×0.014ZEB2
astrocyte activation1198.3×0.015ZEB2
regulation of stress fiber assembly1198.3×0.015PIK3R2
regulation of mitochondrion organization1168.5×0.016AKT3
positive regulation of vascular endothelial cell proliferation1168.5×0.016AKT3
stress fiber assembly1153.2×0.017ZEB2
brain morphogenesis1146.5×0.017AKT3
positive regulation of cell migration involved in sprouting angiogenesis1146.5×0.017AKT3

Therapeutics

Drug target analysis

Approved (phase 4): 3 · Phase ≥3: 3 · Phased (≥1): 3 · Undrugged: 2

Druggability breadth: 3 of 5 evidence-associated genes (60%) have a ChEMBL target (buckets above are over the deeply-mined display cohort).

Genes with an approved drug

The molecule shown is one approved compound that hits the gene — not necessarily a drug of choice or one indicated for this disease.

SymbolExample approved molecule
PIK3R2IDELALISIB
AKT3CAPIVASERTIB
CCND2PALBOCICLIB

Top cohort targets by molecule count

SymbolMoleculesMax phase
AKT3184
PIK3R264
CCND234
ZEB200
ARMC600

Drugs targeting cohort genes (top 30)

MoleculeMax phaseTargets in cohort
IDELALISIB4PIK3R2
INAVOLISIB4PIK3R2
CAPIVASERTIB4AKT3
MIDOSTAURIN4AKT3
PALBOCICLIB4CCND2
TASELISIB3PIK3R2
IPATASERTIB3AKT3
AFURESERTIB3AKT3
ENZASTAURIN3AKT3
FASUDIL3AKT3
LESTAURTINIB3AKT3
RUBOXISTAURIN3AKT3
ALVOCIDIB3CCND2
ROGINOLISIB2PIK3R2
AMDIZALISIB2PIK3R2
PICTILISIB2PIK3R2
MIRANSERTIB2AKT3
MK-22062AKT3
UPROSERTIB2AKT3
AT-131481AKT3
GSK-6906931AKT3
GSK-10709161AKT3
JNJ-264833271AKT3
PF-037583091AKT3
BAY-11259761AKT3
VEVORISERTIB1AKT3
BMS-3870321CCND2

Bioactivity and enzyme data

Enzyme cohort genes (≥1 EC): 2.

Cohort genes with ChEMBL bioactivity (full, sorted by assay count)

SymbolAssaysType breakdown
AKT3660Binding:644, Functional:16
CCND228Binding:28
PIK3R227Binding:27

Cohort enzymes (BRENDA EC)

SymbolEC numbersNames
PIK3R22.7.1.137phosphatidylinositol 3-kinase
AKT32.7.11.1non-specific serine/threonine protein kinase

Cohort genes with high screening signal

≥100 ChEMBL assays — a studied-ness signal; see Therapeutics for approved-drug status.

SymbolChEMBL assays
AKT3660

Pharmacogenomics

Cohort genes with a PharmGKB record: 5; with CPIC/DPWG dosing guidelines: 0.

No cohort gene has a CPIC/DPWG genotype-guided dosing guideline (PharmGKB).

Chemical tractability of cohort targets

27 approved/phased compounds have measured bioactivity against a cohort gene (and aren’t yet in disease-level trials). This is a research / tractability signal, NOT a therapeutic recommendation — a bioactivity row often reflects off-target or screening binding (e.g. promiscuous kinase inhibitors against a cohort kinase), implying no disease mechanism.

CompoundMax phaseCohort target (bioactivity)
IDELALISIB4PIK3R2
INAVOLISIB4PIK3R2
CAPIVASERTIB4AKT3
MIDOSTAURIN4AKT3
PALBOCICLIB4CCND2
TASELISIB3PIK3R2
IPATASERTIB3AKT3
AFURESERTIB3AKT3
ENZASTAURIN3AKT3
FASUDIL3AKT3
LESTAURTINIB3AKT3
RUBOXISTAURIN3AKT3
ALVOCIDIB3CCND2
ROGINOLISIB2PIK3R2
AMDIZALISIB2PIK3R2
PICTILISIB2PIK3R2
MIRANSERTIB2AKT3
MK-22062AKT3
UPROSERTIB2AKT3
AT-131481AKT3
GSK-6906931AKT3
GSK-10709161AKT3
JNJ-264833271AKT3
PF-037583091AKT3
BAY-11259761AKT3
VEVORISERTIB1AKT3
BMS-3870321CCND2

Druggability pyramid

Cohort genes binned by druggability tier (high → low):

TierDefinitionGenesSymbols
AApproved (phase 4 drug)3PIK3R2, AKT3, CCND2
BPhased (≥1) drug, not yet approved0
CDruggable family + PDB, no drug0
DDruggable family + AlphaFold only, no drug0
EDifficult family or no structure, no drug2ZEB2, ARMC6

Undrugged target profiles

2 cohort genes are undrugged. Ranked by ‘starting-point quality’ (assay depth + drugged-partner adjacency).

SymbolChEMBL assaysDrugged partners (top 3)
ZEB20
ARMC60

Clinical trials & evidence

Clinical trials

Clinical trials: 0.