PIP5K1C-Related Neurodevelopmental Disorder

Disease-characteristics research report

Current assessment (15 October 2026). PIP5K1C-related neurodevelopmental disorder is an ultra-rare, autosomal-dominant developmental disorder caused by recurrent de novo gain-of-function missense variants in PIP5K1C. The best-defined phenotype is now named neurodevelopmental disorder with intellectual, visual, and language impairment (NEDVIL; OMIM 621635). It is mechanistically and clinically distinct from lethal congenital contracture syndrome 3 (LCCS3; OMIM 611369), which results from biallelic loss-of-function PIP5K1C variants. The foundational human evidence remains a 2023 cohort of nine unrelated children, so frequencies and prognosis should be treated as provisional. [31][10]

Principal primary source: Morleo M, et al. American Journal of Human Genetics. Published online 13 July 2023; issue date 3 August 2023. PMID 37451268; PMCID PMC10432144; DOI 10.1016/j.ajhg.2023.06.012; URL: https://pubmed.ncbi.nlm.nih.gov/37451268/ [31]

1. Disease information

Definition and scope

NEDVIL is a congenital/early-childhood-onset Mendelian neurodevelopmental syndrome characterized by global developmental delay, intellectual and severe language impairment, motor delay, frequent epilepsy, acquired microcephaly, visual or ophthalmologic abnormalities, and a recognizable but variable craniofacial/skeletal phenotype. In the original cohort, all nine affected children had heterozygous de novo missense variants that increased PIP5KIγ activity and endosomal phosphatidylinositol-4,5-bisphosphate—PI(4,5)P₂—production. [31]

The defining abstract states:

“We identified three de novo heterozygous missense variants in PIP5K1C … in nine unrelated children exhibiting intellectual disability, developmental delay, acquired microcephaly, seizures, visual abnormalities, and dysmorphic features.” — Morleo et al., 2023, PMID 37451268. [31]

Identifiers and names

Common names: PIP5K1C-related neurodevelopmental disorder; PIP5K1C gain-of-function neurodevelopmental disorder; NEDVIL; neurodevelopmental syndrome associated with altered phosphoinositide signaling.

Source granularity: Published information is aggregated from standardized clinical assessments of individual research/clinical cases, not routine population EHR data. Eight cases were identified by exome sequencing and one by genome sequencing; two were enrolled through the Undiagnosed Diseases Network or Telethon Undiagnosed Disease Program, while others were clinically ascertained and connected through Matchmaker Exchange/GeneMatcher. [53]

2. Etiology, risks, protection, and gene–environment interaction

Causal factor

The established cause is a germline heterozygous activating missense variant in the catalytic domain of PIP5KIγ, encoded by PIP5K1C. Three recurrent variants accounted for the original nine cases:

1. NM_012398.3:c.436G>A, p.(Glu146Lys);
2. c.614A>G, p.(Tyr205Cys);
3. c.662A>G, p.(Tyr221Cys). [53]

These variants elevate PI(4,5)P₂, unlike LCCS3-associated biallelic variants that abolish or markedly reduce enzyme function and PI(4,5)P₂ synthesis. [5][19]

Risk and protective factors

The mosaic p.Tyr221Cys individual was the least severely affected and had an IQ of 67, providing preliminary evidence for a dosage relationship; this is based on one case and requires replication. [40]

3. Phenotypes

Cohort-level phenotype summary

Frequencies below are from only nine affected individuals aged 3–15 years and are not population estimates. [32]

Additional findings included myopia, hyperopia, astigmatism, nystagmus, delayed or deficient myelination, abnormal ventricular contours, cerebral atrophy, Chiari I malformation, hypoplastic anterior temporal lobes, coronal synostosis, prominent metopic ridge, talipes equinovarus, coxa valga, camptodactyly, clinodactyly, pes planus, and small feet. MRI findings were heterogeneous and were considered normal, nonspecific, or inconsistent on centralized review in the subset available. [53]

No disease-specific EQ-5D, SF-36, PROMIS, caregiver-burden or adaptive-behavior study has been published. The principal expected QOL burdens arise from nonverbal status, impaired mobility, epilepsy, visual impairment, intellectual disability, and lifelong dependence.

4. Genetic and molecular information

Gene and protein

NEDVIL variants

All are missense substitutions in the amino-terminal portion of the kinase domain. Structural modeling suggested that Tyr205Cys and Tyr221Cys enlarge the ATP-binding-pocket cavity, potentially improving ATP access, whereas Glu146Lys changes local surface charge; those structural effects are inferred, while excess PI(4,5)P₂ production was experimentally demonstrated. [53]

Distinct recessive allelic disorder

Biallelic loss-of-function PIP5K1C variants cause LCCS3: severe fetal akinesia/arthrogryposis, muscle atrophy, growth restriction and early death from respiratory insufficiency. The original homozygous p.Asp253Asn variant abolished kinase activity. A 2024 report added compound-heterozygous frameshifts c.949_952dup, p.(Ser318Ilefs28), and c.688_689del, p.(Gly230Glnfs114), in two affected fetuses. PMID 38491417, published 15 March 2024; URL: https://pubmed.ncbi.nlm.nih.gov/38491417/ [34]

Important curation rule: do not merge dominant gain-of-function NEDVIL with recessive loss-of-function LCCS3 into a single phenotype.

Other molecular categories

• Modifier genes: none validated.
• Epigenetic signature: no NEDVIL-specific methylation episignature or pathogenic chromatin mechanism reported.
• Chromosomal abnormalities: no recurrent deletion, duplication, inversion or translocation defines the disorder.
• Somatic disease: no somatic oncogenic mechanism is established; the one mosaic case reflects postzygotic constitutional mosaicism.
• Allele frequency: exact gnomAD allele counts were not given for all three variants; pathogenic dominant variants are expected to be absent or extremely rare because of severe pediatric disease.
• Pharmacogenomics: no PIP5K1C-specific drug–gene prescribing guideline exists.

5. Environmental information

No toxin, radiation, pollution, diet, smoking, alcohol, occupation, lifestyle behavior or infectious agent is known to initiate NEDVIL. It is not infectious, contagious or zoonotic. Environmental and health-care factors may influence secondary outcomes—especially seizure control, nutrition, contractures, communication and visual development—but they are not established causes.

Consequently:

• CTD-style chemical associations with PIP5K1C should not be interpreted as proven disease risks.
• Vaccination, dietary avoidance and exposure reduction do not prevent the underlying variant.
• Standard infection prevention remains important in children with impaired mobility or feeding, but is supportive rather than disease-specific.

6. Mechanism and pathophysiology

Ordered causal chain

1. A heterozygous de novo activating missense variant in the PIP5K1C kinase domain leads to excessive PIP5KIγ catalytic output.
2. Increased PIP5KIγ activity leads to increased conversion of PI4P to PI(4,5)P₂, particularly in the early-endosomal compartment.
3. Excess endosomal PI(4,5)P₂ leads to ectopic recruitment/polymerization of filamentous actin on EEA1-positive early endosomes.
4. Abnormal actin coating results in defective early-endosomal cargo sorting and recycling, demonstrated by slower transferrin-receptor recycling.
5. Defective membrane trafficking during development is inferred to lead to altered neuronal/synaptic development and function and impaired forebrain, eye and craniofacial morphogenesis.
6. These developmental abnormalities result in developmental delay, intellectual and language impairment, epilepsy, acquired microcephaly, visual dysfunction and dysmorphism.
7. Branch: altered trafficking and cytoskeletal regulation in developing skeletal/craniofacial tissues is inferred to lead to cranial-suture and limb/skeletal abnormalities.
8. Severity branch: lower postzygotic variant burden from mosaicism may lead to a milder phenotype; this is supported by one individual only.

Morleo et al. summarized the central result as:

“The PIP5K1C variants result in an increase of the endosomal PI(4,5)P2 pool, giving rise to ectopic recruitment of filamentous actin at early endosomes … that in turn causes dysfunction in EE trafficking.” [31]

Experimental support

The authors caution that “the mechanistic link bridging these PIP5K1C gain-of-function variants … and the clinical manifestation … remain[s] to be determined and need[s] to be explored in neuronal tissue.” Thus, the lipid/endosome defect is demonstrated, but its precise neuronal-cell-type consequences remain partly inferred. [53]

Suggested ontology annotations

No disease-specific transcriptomic, proteomic, metabolomic, lipidomic, single-cell, spatial-transcriptomic or integrated multi-omic patient dataset has been reported. The direct lipid-immunostaining and trafficking assays are currently the most informative molecular profiling.

7. Anatomical structures affected

No consistent laterality is established. Eye and brain findings may be bilateral or asymmetric depending on the manifestation.

8. Temporal development

• Onset: congenital molecular lesion with manifestations emerging in infancy or early childhood. Motor and speech delay become apparent as milestones are missed; postnatal microcephaly develops after relatively less abnormal birth head circumference in many cases.
• Course: chronic and lifelong. Development may continue slowly, but affected children generally remain substantially delayed.
• Epilepsy: variable; infantile spasms were the first severe epilepsy presentation in three children.
• Progression: acquired microcephaly and scoliosis can evolve with age. There is no evidence for a primary neurodegenerative course, although follow-up only extended to age 15 years.
• Stages: no validated staging system exists.
• Remission: no spontaneous remission of the neurodevelopmental syndrome is reported. Individual seizures may respond to treatment, but response rates are unavailable.
• Critical periods: prenatal and early postnatal brain, visual-system and craniofacial development are likely biologically critical. Early seizure recognition, visual habilitation and developmental therapy are practical intervention windows, although no NEDVIL-specific controlled evidence exists.

9. Inheritance and population

At the time of the 2023 report, only nine molecularly confirmed NEDVIL cases were described. Therefore, neither prevalence per 100,000 nor annual incidence can be calculated responsibly.

10. Diagnostics

Recommended diagnostic approach

1. Recognize the phenotype: unexplained global developmental delay/intellectual disability with profound speech impairment, motor delay, acquired microcephaly, epilepsy and visual abnormalities, particularly with prominent upper lip/maxilla, micrognathia or skeletal findings.
2. Order trio exome or genome sequencing, preferably with copy-number analysis and sufficient read-level review to detect low-level mosaicism. ACMG strongly recommends exome/genome sequencing as a first- or second-tier test for pediatric congenital anomalies or DD/ID. PMID 34211152, published July 2021; URL: https://pubmed.ncbi.nlm.nih.gov/34211152/ [120][122]
3. Alternatively, use a comprehensive neurodevelopmental/epilepsy panel that includes PIP5K1C and detects single-nucleotide variants, small indels and mosaicism.
4. Confirm a candidate variant by an orthogonal method if needed and test both parents to establish de novo occurrence.
5. Interpret mechanism-specifically: dominant catalytic-domain activating missense variants support NEDVIL; biallelic loss-of-function variants support LCCS3.
6. Reanalyse negative exome/genome data as gene–disease knowledge evolves.

Utility of test types

Clinical assessments after diagnosis

• Developmental, cognitive, language and adaptive-function testing.
• EEG for seizures, regression, suspicious spells or sleep-related events.
• Brain MRI, particularly with epilepsy, microcephaly, focal neurologic signs or regression.
• Formal ophthalmology and functional-vision assessment.
• Serial head circumference, height, weight and nutritional review.
• Orthopedic examination for scoliosis, contractures, feet/hip abnormalities.
• Craniofacial/neurosurgical evaluation if craniosynostosis is suspected.
• Feeding/swallowing assessment where clinically indicated.

No standardized clinical criteria or laboratory biomarker can replace molecular diagnosis.

Differential diagnosis

Broad differentials include genetic developmental and epileptic encephalopathies, phosphoinositide disorders such as Lowe syndrome and other PI-metabolism disorders, syndromic microcephaly with visual impairment, tubulinopathies/cortical-malformation syndromes, and other disorders with severe speech impairment and craniosynostosis. Distinguishing NEDVIL requires the characteristic PIP5K1C activating variant and, when needed, functional evidence.

11. Outcome and prognosis

• Survival: no NEDVIL deaths were reported through ages 3–15 years. Five- and ten-year survival rates and life expectancy are unknown.
• Development: morbidity is substantial. Most original cases were nonverbal or minimally verbal, and several remained non-ambulatory.
• Epilepsy: present in 7/9; infantile spasms/DEE in 3/9 may predict greater developmental burden.
• Vision: visual or ocular abnormalities affected 8/9 and may compound developmental disability.
• Prognostic indicators: mosaicism/lower variant burden may be associated with milder severity; epilepsy severity, degree of visual impairment and ability to acquire independent mobility are plausible clinical predictors but are unvalidated.
• Recovery: no cure or reversal of the developmental phenotype has been reported. Developmental gains can occur, and functional potential may improve with seizure control, vision support, communication systems and rehabilitation.
• Disease-specific mortality: unknown and not shown to be elevated in the limited NEDVIL cohort.
• Do not extrapolate LCCS3 mortality: perinatal respiratory death is characteristic of severe recessive loss of function, not demonstrated for dominant NEDVIL.

12. Treatment and management

There is no approved disease-modifying treatment, no published NEDVIL treatment trial, and no reliable treatment-response percentage. Management is multidisciplinary and manifestation-directed.

Experimental approaches

Because disease variants increase PIP5KIγ activity, selective kinase inhibition is mechanistically attractive. Morleo et al. stated, “From a clinical point of view, PIP5Ks represent attractive therapeutic targets,” but no rescue was demonstrated in patient neurons or affected children. [109]

UNC3230 lowers PIP₂ in dorsal-root-ganglion neurons and reduced nociceptive hypersensitivity in mouse pain models, but it also inhibits PIP4K2C and has not been tested as NEDVIL therapy. PMID 24853942. [110] In 2024, medicinal-chemistry work reported novel potent bicyclic-pyrazole PIP5K1C inhibitors, but these remain preclinical and have no established pediatric CNS safety, selectivity, dosing or developmental benefit. [107]

Gene replacement would be biologically inappropriate without allele-specific control because NEDVIL is a gain-of-function disorder. Potential future strategies include allele-selective silencing, targeted RNA interference/ASOs or selective PIP5KIγ inhibition, but none has entered disease-specific clinical testing.

13. Prevention

Primary prevention

There is no lifestyle, vaccine or environmental intervention that prevents a spontaneous de novo mutation. General preconception health measures do not specifically alter NEDVIL risk.

Secondary prevention and early detection

• Prompt genetic evaluation of unexplained DD/ID, epilepsy, postnatal microcephaly and visual impairment.
• Early EEG when spasms or developmental regression are suspected.
• Early ophthalmology/functional-vision assessment.
• Immediate developmental, speech, PT/OT and AAC referral without waiting for a molecular diagnosis.

There is no newborn biochemical screening program for NEDVIL and insufficient evidence to support population screening.

Reproductive prevention/counseling

• Offer formal genetic counseling after molecular confirmation.
• Test parents using a method sensitive to low-level mosaicism where possible.
• If the variant is absent from parental blood, recurrence risk is low but not zero because of possible germline mosaicism.
• If a parent is mosaic or constitutionally positive, recurrence risk may approach 50%, modified by germline allele fraction.
• Targeted prenatal diagnosis by chorionic-villus sampling or amniocentesis and preimplantation genetic testing for monogenic disease are technically feasible after identification of the familial variant.
• Cascade testing is appropriate for a mosaic/affected parent or an unexpectedly familial variant, but routine testing of distant relatives is not useful for a confirmed de novo case.

Tertiary prevention

Prevent secondary complications through seizure control, aspiration and nutrition surveillance, mobility/contracture programs, scoliosis monitoring, visual habilitation, communication support and individualized educational planning.

14. Other species and naturally occurring disease

No well-established naturally occurring PIP5K1C-associated veterinary syndrome, breed predisposition or OMIA disease entry was identified. Consequently, no VBO breed term is applicable. There is no zoonotic transmission or cross-species contagion.

The pathway is evolutionarily conserved: zebrafish pip5k1ca and pip5k1cb proteins were reported as approximately 71% and 62% identical to human PIP5KIγ, respectively, supporting comparative functional modeling.

15. Model organisms and experimental systems

In the landmark knockout mouse study, reduced brain PI(4,5)P₂ produced decreased miniature-current frequency, enhanced synaptic depression, a smaller readily releasable vesicle pool, delayed endocytosis and slower vesicle recycling. PMID 15386003. This establishes that tightly regulated PIP5KIγ activity is essential for synaptic-vesicle trafficking, although it models deficient rather than excessive kinase activity. [72]

Evidence appraisal and knowledge gaps

1. Human evidence strength: convincing gene–disease relationship based on recurrent de novo variants, clustering in the kinase domain, functional gain-of-function data and in-vivo zebrafish phenocopy.
2. Main limitation: only nine published NEDVIL individuals in the defining cohort; ascertainment strongly favors severe pediatric cases.
3. Key unresolved questions: full variant spectrum, penetrance, adult natural history, epilepsy treatment response, genotype–phenotype correlations, neuronal and retinal cell-type mechanisms, and whether selective kinase inhibition can safely normalize—not over-suppress—PI(4,5)P₂.
4. Ontology caution: MONDO:1010145 could not be independently verified against the accessible records; OMIM 621635/NEDVIL is currently the most specific, clearly supported disease identifier.
5. Clinical distinction: dominant gain-of-function NEDVIL and recessive loss-of-function LCCS3 must remain separate knowledge-base entities, connected as allelic disorders rather than synonyms.

Reference Validation

Checked with linkml-reference-validator 0.3.0.

References that may not be about this subject

These identifiers resolve, so they are not fabrications, but the records they resolve to share almost none of this report's vocabulary. That is a clue and not a verdict - a paper can be relevant in ways its title and abstract do not spell out - so read them before deciding:

• PMID:34211152 (2 mentions) - Exome and genome sequencing for pediatric patients with congenital anomalies or intellectual disability: an evidence-based clinical guideline of the American College of Medical Genetics and Genomics (ACMG).
• shared terms: developmental

Weighed against this report's own most characteristic terms: nedvil, variant, pip5k1c, developmental, visual, phenotype, epilepsy, microcephaly, disease, impairment, novo, craniofacial, abnormalitie, severe, disorder, affected, function, mosaicism, dominant, individual.

All extracted references resolved successfully. Resolving is not the same as being relevant, though - see the references listed above as possibly off topic.

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

• MONDO:1010145 (2 mentions) - the report calls it "MONDO supplied in request"; MONDO calls it PIP5K1C-related neurodevelopmental disorder

Terms named inconsistently

The report gives these identifiers more than one name of its own:

• HGNC:8996 - called "PIP5K1C", "HGNC"

Prefixes with no resolver

Terms carrying these prefixes were not checked either way, because no configured ontology covers them. An unrecognised prefix may name an ontology this run could not reach as easily as one that does not exist, so nothing here is evidence of fabrication: ORPHA, MGI.