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Classifications

Harrison's Part

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Inheritance

1

Autosomal dominant inheritance HP:0000006

NEDDFL results from a heterozygous loss-of-function allele of BPTF; the gene is dosage-sensitive and a single null allele is sufficient to cause disease. Most reported variants arose de novo, but transmission from a mildly affected parent has been documented in four families, establishing autosomal dominant inheritance with variable expressivity rather than exclusively de novo occurrence. Transmitting parents range from isolated microcephaly without reported developmental delay, through learning disability with independent adult function, to a phenotype comparable to that of the proband. Penetrance has not been quantified.

Autosomal dominant inheritance Expressivity: VARIABLE

Show evidence (3 references)

PMID:28942966 SUPPORT Human Clinical

"we report eight loss-of-function and two missense variants (eight de novo and two of unknown origin) in BPTF on 17q24.2"

Establishes heterozygous, predominantly de novo variation at a single locus as the molecular basis, consistent with autosomal dominant inheritance.

PMID:33522091 SUPPORT Human Clinical

"Our study has also uncovered four cases of inherited BPTF variants, providing some insight into the penetrance and expressivity of NEDDFL."

Documented parent-to-child transmission confirms dominant inheritance and demonstrates that the disorder is not exclusively de novo.

PMID:33522091 SUPPORT Human Clinical

"The histories reported in these patients and the presence of inherited pathogenic variants in BPTF do suggest a pattern of variable expressivity in NEDDFL."

Directly supports the recorded VARIABLE expressivity of the dominant allele.

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Discussions and Knowledge Gaps

2

Why does BPTF haploinsufficiency cause microcephaly when loss of its NURF ATPase partner SMARCA1/SNF2L causes brain overgrowth?

KNOWLEDGE GAP OPEN bptf_vs_smarca1_dosage_paradox

Attached to

pathophysiology#Impaired NURF Chromatin-Remodeling Activity

The simplest model of NEDDFL is that reduced BPTF impairs NURF, and impaired NURF impairs cortical neurogenesis. That model predicts that removing the NURF catalytic ATPase should phenocopy BPTF loss. It does not: Smarca1-null mice have enlarged brains, the direct opposite of the NEDDFL phenotype. This means either that BPTF has NURF-independent functions in the developing cortex, or that the two subunits have opposing dosage effects on the same complex, or that SNF2H-containing complexes compensate for Smarca1 loss but not for Bptf loss. Which of these is true determines whether NURF is actually the right therapeutic target concept for NEDDFL.

Proposed experiments

Side-by-side cortical comparison of Bptf and Smarca1 conditional knockouts

bptf_smarca1_side_by_side_cortex

Compare cortical transcriptomes and progenitor kinetics side by side in forebrain-conditional Bptf and Smarca1 knockouts on the same genetic background, to determine whether the dysregulated gene sets overlap or diverge.

BPTF and SNF2L chromatin co-occupancy mapping in cortical progenitors

bptf_snf2l_cooccupancy_map

Map BPTF chromatin occupancy in cortical progenitors and ask what fraction of BPTF-bound sites are also SNF2L-bound, to quantify the size of the NURF-independent BPTF binding compartment.

Test whether the BPTF-MYC axis accounts for the Bptf-specific microcephaly

bptf_myc_axis_microcephaly_test

Test whether the NURF-independent BPTF interactome, including the MYC cofactor axis identified by RNA-seq binding-site enrichment, accounts for the microcephaly that Smarca1 loss fails to reproduce.

Show evidence (1 reference)

PMID:35604347 SUPPORT Model Organism

"Surprisingly, ablation of Smarca1 resulted in mice with enlarged brains, a direct contrast to the phenotype of NEDDFL patients."

This is the observation that creates the gap: the NURF ATPase knockout gives the opposite brain-size phenotype to BPTF loss.

Does the homozygous forebrain-conditional Bptf knockout mouse faithfully model human BPTF haploinsufficiency, given that heterozygous animals show little to no phenotype?

HUMAN MODEL MISMATCH OPEN bptf_mouse_homozygous_vs_human_haploinsufficiency

Attached to

pathophysiology#Cortical Hypoplasia and Disrupted Lamination

Human NEDDFL is a heterozygous, dosage-sensitivity disorder: one null allele produces microcephaly, intellectual disability, and speech delay. The principal mouse model is a homozygous conditional null restricted to the forebrain, and heterozygous mice were reported to have little to no phenotype. The mouse's severe cortical hypoplasia is therefore a complete-loss phenotype, not a half-dosage phenotype, and the cellular mechanism it reveals (prolonged progenitor cell cycle, increased apoptosis, lamination failure) may be quantitatively or qualitatively different from what a 50% reduction produces in a human cortex. The species difference in dosage sensitivity is itself the open question. This is a translational validity problem, not an absence of evidence, hence HUMAN_MODEL_MISMATCH rather than KNOWLEDGE_GAP.

Proposed experiments

Deep cortical phenotyping of Bptf heterozygous mice

bptf_het_mouse_deep_phenotyping

Phenotype Bptf heterozygous mice quantitatively for cortical volume, laminar composition, and progenitor kinetics rather than by gross inspection, to establish whether a subtle half-dosage phenotype exists.

Isogenic heterozygous BPTF-null human cortical organoids

bptf_het_ipsc_cortical_organoid

Derive isogenic human iPSC lines carrying patient BPTF null alleles in the heterozygous state and assay cortical organoid size, progenitor cell cycle length, and deep-layer neuron output against isogenic controls.

Cross-species BPTF dosage-response comparison

bptf_dosage_response_cross_species

Compare BPTF dosage-response curves for NURF assembly and target-gene expression between mouse and human cortical progenitors, to test whether the human system is simply steeper.

Show evidence (1 reference)

PMID:35604347 SUPPORT Model Organism

"To model the NEDDFL syndrome, we generated forebrain-specific Bptf knockout (Bptf conditional Knockout (cKO)) mice."

Identifies the model whose homozygous conditional-null design is the source of the mismatch with the human heterozygous disorder.

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Pathophysiology

8

BPTF Haploinsufficiency

A heterozygous loss-of-function allele of BPTF at 17q24.2 (frameshift, nonsense, splice-site, exonic or whole-gene deletion, or gene-disrupting translocation) halves functional BPTF protein dosage. BPTF is dosage-sensitive: unlike many chromatin genes, one null allele produces overt human disease, and BPTF is the NURF-exclusive subunit, so its loss cannot be compensated by the other ISWI complexes that share the SNF2L/SNF2H ATPases.

BPTF hgnc:3581

Animal models

Constitutive Bptf-null mouse embryo Mus musculus perturbs Establishes that Bptf dosage is developmentally critical in a mammal, which is the premise that makes a 50% reduction a credible human disease mechanism.

Downstream

Impaired NURF Chromatin-Remodeling Activity Reduced BPTF protein lowers the amount of assembled, chromatin-engaged NURF and its recruitment of the SNF2L ATPase to target promoters.

Show evidence (2 references)

PMID:28942966 SUPPORT Human Clinical

"our data demonstrate the pathogenic role of BPTF haploinsufficiency in syndromic neurodevelopmental anomalies and extend the clinical spectrum of human disorders caused by ablation of chromatin remodeling complexes"

States haploinsufficiency as the disease mechanism.

PMID:33522091 SUPPORT Human Clinical

"Haploinsufficiency of BPTF in humans leads to the clinical entity known as neurodevelopmental disorder with dysmorphic facies and distal limb anomalies (NEDDFL, MIM#617755)."

Links reduced BPTF dosage directly to the named clinical entity.

Impaired NURF Chromatin-Remodeling Activity

BPTF is the largest subunit of NURF, an ISWI-family ATP-dependent chromatin-remodeling complex containing the SNF2L/SMARCA1 ATPase. BPTF reads active-chromatin marks - H3K4me3 through its PHD finger and H4K16ac through its bromodomain - and this reading is what tethers NURF to active promoters and delivers the SNF2L ATPase there for nucleosome sliding. When BPTF is reduced, NURF occupancy at H3K4me3-marked promoters falls and ATP-dependent nucleosome repositioning at those promoters is impaired.

ATP-dependent chromatin remodeling GO:0006338 ↓ DECREASED

BPTF PHD finger reading of H3K4me3 GO:0140002 ↓ DECREASED NURF nucleosome sliding GO:0140750 ↓ DECREASED

Downstream

Dysregulated Developmental Gene Transcription Loss of NURF-mediated nucleosome remodeling at developmental promoters changes the transcriptional output of those genes.

Show evidence (4 references)

PMID:28942966 SUPPORT Human Clinical

"Bromodomain PHD finger transcription factor (BPTF) is the largest subunit of nucleosome remodeling factor (NURF), a member of the ISWI chromatin-remodeling complex."

Establishes BPTF's identity as the largest NURF subunit within the ISWI family.

PMID:16728976 SUPPORT In Vitro

"Here we show that a plant homeodomain (PHD) finger of nucleosome remodelling factor (NURF), an ISWI-containing ATP-dependent chromatin-remodelling complex, mediates a direct preferential association with H3K4me3 tails."

Defines the molecular reader function of the BPTF PHD finger that is lost when BPTF dosage falls.

PMID:16728976 SUPPORT In Vitro

"Depletion of H3K4me3 causes partial release of the NURF subunit, BPTF (bromodomain and PHD finger transcription factor), from chromatin and defective recruitment of the associated ATPase, SNF2L (also known as ISWI and SMARCA1), to the HOXC8 promoter."

Demonstrates the mechanistic coupling between BPTF chromatin engagement and delivery of the SNF2L remodeling ATPase to a developmental promoter.

+ 1 more reference

Dysregulated Developmental Gene Transcription

NURF target genes are enriched for developmental regulators. Loss of BPTF misregulates homeobox/HOX transcription factors, SMAD-pathway targets, and fate-determining transcription factors; dysregulated genes in the Bptf conditional-knockout mouse cortex are enriched for MYC binding sites, MYC being a known BPTF transcriptional cofactor. The consequence is not global transcriptional collapse but loss of correct spatial and temporal control of a developmental gene program.

regulation of transcription by RNA polymerase II GO:0006357 ⚠ ABNORMAL anterior/posterior pattern specification GO:0009952 ⚠ ABNORMAL

Downstream

Neural Progenitor Cell-Cycle Prolongation and Apoptosis Misexpression of fate-determining transcription factors and apoptotic-signaling pathway genes impairs progenitor proliferation and survival.

Disrupted Craniofacial and Limb Patterning Loss of correct HOX/homeobox spatial patterning perturbs craniofacial and distal limb morphogenesis.

Show evidence (4 references)

PMID:16728976 SUPPORT In Vitro

"Loss of BPTF in Xenopus embryos mimics WDR5 loss-of-function phenotypes, and compromises spatial control of Hox gene expression."

Directly demonstrates that BPTF loss dysregulates spatial developmental gene expression in a vertebrate embryo.

PMID:18974875 SUPPORT Model Organism

"Microarray analysis at early stages of differentiation has identified Bptf-dependent gene targets including homeobox transcriptions factors and genes essential for the development of ectoderm, mesoderm, and both definitive and visceral endoderm."

Identifies homeobox transcription factors and germ-layer developmental genes as the transcriptional targets that depend on Bptf.

PMID:35604347 SUPPORT Model Organism

"RNAseq and pathway analysis identified altered expression of fate-determining transcription factors and the biological pathways involved in neural development, apoptotic signaling and amino acid biosynthesis."

In the disease-specific forebrain Bptf knockout, the transcriptional consequence is misexpression of fate-determining transcription factors and neural-development/apoptosis pathways.

+ 1 more reference

Neural Progenitor Cell-Cycle Prolongation and Apoptosis

In the developing forebrain, loss of Bptf prolongs neural progenitor cell cycle length and raises the incidence of programmed cell death, so fewer neurons are produced from the progenitor pool. Independently, CRISPR knockout of bptf in zebrafish increases apoptosis (TUNEL) in the developing head. Reduced neuronal output from a depleted and slow-cycling progenitor pool is the proximate cellular cause of the reduced brain size.

cortical neural progenitor cell CL:0011020

neural precursor cell proliferation GO:0061351 ↓ DECREASED apoptotic process GO:0006915 ↑ INCREASED cell cycle GO:0007049 ⚠ ABNORMAL

Animal models

Bptf forebrain-conditional knockout mouse Mus musculus recapitulates The model directly demonstrates the cellular mechanism this node asserts: prolonged progenitor cell cycle length and increased programmed cell death reducing neuronal output from the progenitor pool.

Downstream

Cortical Hypoplasia and Disrupted Lamination Reduced neuronal output from a slow-cycling, apoptosis-prone progenitor pool yields a hypoplastic cortex.

Show evidence (2 references)

PMID:35604347 SUPPORT Model Organism

"Prolonged progenitor cell cycle length and a high incidence of cell death reduced the neuronal output."

Direct statement of the cellular mechanism in the disease-specific forebrain-conditional Bptf knockout mouse.

PMID:28942966 SUPPORT Model Organism

"showed a significant increase in cell death in F0 mutants compared to controls"

Independent, cross-species (zebrafish) confirmation that bptf loss increases apoptosis during neurodevelopment.

Cortical Hypoplasia and Disrupted Lamination

Reduced neuronal output produces severe cortical hypoplasia with a disrupted laminar architecture: the proportion of deep-layer neurons is reduced and neuronal maturation defects impair the acquisition of distinct cortical cell fates such as Ctip2-positive identity. This is the tissue-level substrate of the postnatal microcephaly and the mild structural brain abnormalities seen on human MRI.

cortical projection neuron CL:0000540

cerebral cortex development GO:0021987 ⚠ ABNORMAL cerebral cortex neuron differentiation GO:0021895 ↓ DECREASED

cerebral cortex UBERON:0000956

Animal models

Bptf forebrain-conditional knockout mouse Mus musculus recapitulates Reproduces both facets of the node: severe cortical hypoplasia, and disrupted lamination with reduced deep-layer neurons and impaired acquisition of distinct cortical cell fates.

Downstream

Postnatal Microcephaly and Growth Restriction

Neurodevelopmental Impairment A hypoplastic, mislaminated cortex with impaired neuronal fate acquisition underlies the cognitive, language, and motor phenotype.

Structural Brain Abnormality The hypoplastic, mislaminated cortex is what the mild non-specific structural changes on human brain MRI depict.

Epilepsy A cortex built with reduced deep-layer neurons and impaired fate acquisition is an epileptogenic substrate, consistent with developmental delay preceding seizure onset. The circuit-level route from mislamination to seizures has not been established in NEDDFL, hence unknown intermediates.

EEG Abnormality The same abnormal cortex produces interictal epileptiform discharges in individuals who never have clinical seizures.

Show evidence (2 references)

PMID:35604347 SUPPORT Model Organism

"The Bptf cKO mice were born in normal Mendelian ratios, survived to adulthood but were smaller in size with severe cortical hypoplasia."

Establishes cortical hypoplasia with reduced body size as the tissue-level phenotype of forebrain Bptf loss.

PMID:35604347 SUPPORT Model Organism

"Cortical lamination was also disrupted with reduced proportions of deep layer neurons, and neuronal maturation defects that impaired the acquisition of distinct cell fates"

Documents the laminar and cell-fate component of the cortical phenotype.

Disrupted Craniofacial and Limb Patterning

Loss of BPTF-dependent spatial control of homeobox gene expression perturbs morphogenesis of the craniofacial skeleton and the distal limb. In zebrafish bptf F0 mutants the ceratohyal angle of the craniofacial skeleton is substantially increased, an established readout of abnormal craniofacial patterning. In humans the corresponding findings are the mild dysmorphic facial gestalt and the distal limb anomalies (cutaneous toe syndactyly, sandal gap, fifth-finger clinodactyly) that name the syndrome. The mechanism connecting BPTF dosage to the specific human limb findings has not been directly demonstrated and is inferred from the patterning role of NURF, so this node is marked PROVISIONAL.

migratory cranial neural crest cell CL:0000008

embryonic skeletal system morphogenesis GO:0048704 ⚠ ABNORMAL embryonic limb morphogenesis GO:0030326 ⚠ ABNORMAL

Animal models

bptf CRISPR F0 crispant zebrafish Danio rerio recapitulates Increased ceratohyal angle is an established quantitative readout of disrupted craniofacial patterning, and is the direct experimental support for the craniofacial arm of this node.

Downstream

Dysmorphic Facial Features Disrupted cranial neural crest patterning of the facial skeleton is expressed as the mild recognizable facial gestalt.

Distal Limb Anomalies The same patterning perturbation in the autopod is expressed as the mild hand and foot anomalies that name the syndrome. Inherits this node's PROVISIONAL status: the limb arm is inferred from the patterning role of NURF and has not been directly demonstrated.

Show evidence (3 references)

PMID:28942966 SUPPORT Model Organism

"we observed a substantial increase of the ceratohyal angle of the craniofacial skeleton in bptf F0 mutants, indicating abnormal craniofacial patterning"

Experimental demonstration that bptf loss disrupts craniofacial patterning, the model-organism correlate of the human dysmorphic facies.

PMID:16728976 SUPPORT In Vitro

"NURF-mediated ATP-dependent chromatin remodelling is directly coupled to H3K4 trimethylation to maintain Hox gene expression patterns during development"

Supplies the HOX-patterning link that makes limb and craniofacial patterning a plausible consequence of BPTF loss; indirect with respect to the human limb findings, hence PARTIAL.

PMID:33522091 SUPPORT Human Clinical

"The mechanism for these abnormalities is less clear, though it is presumed that they are also derived from abnormal signaling during embryogenesis similar to the distal limb defects commonly described in these patients."

The disease literature itself states the developmental-patterning inference is presumptive, which is why this node is PROVISIONAL.

Postnatal Microcephaly and Growth Restriction

Reduced brain growth manifests as postnatal (secondary) microcephaly rather than congenital microcephaly in most individuals: head circumference is frequently normal at birth and falls below the third percentile over infancy and childhood. Reduced somatic growth accompanies it, with poor weight gain, malnutrition, and short stature; a subset has documented growth hormone deficiency.

Animal models

bptf CRISPR F0 crispant zebrafish Danio rerio partially recapitulates Reduced head size in bptf F0 larvae is the cross-species correlate of the human microcephaly.

Downstream

Neurodevelopmental Impairment Reduced brain volume co-occurs with, and is a biomarker of, the underlying neurodevelopmental deficit.

Postnatal Microcephaly Reduced postnatal brain growth is measured clinically as a head circumference falling below the third percentile after birth.

Short Stature The somatic arm of the growth restriction presents as height below the third percentile, with growth hormone deficiency documented in a subset.

Poor Weight Gain and Malnutrition The same growth restriction presents as poor weight gain and moderate to severe malnutrition, compounded by the feeding difficulty.

Show evidence (3 references)

PMID:28942966 SUPPORT Human Clinical

"who manifest variable degrees of developmental delay/intellectual disability (10/10), speech delay (10/10), postnatal microcephaly (7/9), and dysmorphic features (9/10)"

Establishes the postnatal (rather than congenital) timing of the microcephaly in the founding cohort.

PMID:28942966 SUPPORT Model Organism

"Using CRISPR-Cas9 genome editing of bptf in zebrafish to induce a loss of gene function, we observed a significant reduction in head size of F0 mutants compared to control larvae."

Model-organism recapitulation of reduced head size on bptf loss.

PMID:33522091 SUPPORT Human Clinical

"At the time of their most recent clinical assessment, 5/20 (25%) individuals exhibited short stature for age and 10/19 (53%) individuals had decreased weight for age"

Quantifies the somatic growth restriction that accompanies the microcephaly.

Neurodevelopmental Impairment

The organism-level clinical output: global developmental delay and intellectual disability with disproportionate speech and language delay, motor delay, and hypotonia, spanning a wide severity range from severe impairment to mild learning difficulty compatible with independent adult life. In a minority, cortical excitability is sufficiently disturbed to produce early-childhood-onset epilepsy or isolated interictal epileptiform discharges; developmental delay precedes seizure onset, indicating that the epilepsy is a consequence of the abnormal cortex rather than its cause.

Downstream

Global Developmental Delay The impairment presents first as delayed attainment of milestones across all developmental domains.

Intellectual Disability The developmental delay matures into persisting cognitive impairment.

Delayed Speech and Language Development Speech and language are disproportionately affected relative to other domains, making this the most consistent single manifestation.

Motor Delay Gross and fine motor milestones are delayed alongside the cognitive and language domains.

Hypotonia Reduced muscle tone in infancy is part of the same impairment and contributes to the motor delay and feeding difficulty.

Show evidence (2 references)

PMID:33522091 SUPPORT Human Clinical

"Common features included DD and/or ID (23/26, 88%), speech delay (22/26, 85%), head circumference less than the third percentile for age (11/26, 42%), motor delay (18/26, 69%), hypotonia (10/26, 38%), and dysmorphic features (20/26, 77%)."

Quantifies the organism-level clinical output across the largest single-study cohort.

PMID:38936258 SUPPORT Human Clinical

"developmental delay preceding seizure onset"

Establishes the temporal ordering that makes epilepsy a downstream consequence of the abnormal cortex rather than a driver of the developmental delay.

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Pathograph

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Phenotypes

25

Digestive 1

Feeding Difficulties HP:0011968

Frequency omitted: PMID:33522091 reports poor feeding qualitatively as an increased-frequency finding without a numerator/denominator.

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"In addition to DDs, microcephaly, and distal limb defects, our cohort exhibited an increased frequency of ophthalmologic abnormalities, poor weight gain/poor feeding, and cutaneous syndactyly of the toes."

Names poor feeding as an expanded feature of NEDDFL.

Eye 1

Myopia HP:0000545

Frequency omitted for the same denominator ambiguity as exotropia.

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"Interestingly, 13 individuals demonstrated mild ophthalmologic abnormalities. These included the finding of exotropia in six individuals, strabismus in two individuals, and confirmed myopia in three individuals."

Documents confirmed myopia in the cohort.

Head and Neck 4

Postnatal Microcephaly FREQUENT Secondary microcephaly HP:0005484

Onset: INFANTILE

Frequency band from PMID:33522091 (head circumference less than the third percentile for age 11/26, 42% -> FREQUENT); the pooled table in PMID:36153657 reports 18/37 (49%), concordant. The secondary (postnatal) classification rests on the same paper's contrast between 12/20 (60%) below the third percentile at last assessment and 4/10 (40%) at birth, and on the founding cohort explicitly naming the microcephaly postnatal.

Show evidence (2 references)

PMID:28942966 SUPPORT Human Clinical

"who manifest variable degrees of developmental delay/intellectual disability (10/10), speech delay (10/10), postnatal microcephaly (7/9), and dysmorphic features (9/10)"

Names the microcephaly as postnatal and reports it in 7/9 assessed individuals in the founding cohort.

PMID:33522091 SUPPORT Human Clinical

"12/20 (60%) individuals demonstrated a head circumference less than the third percentile for age"

Quantifies microcephaly at last clinical assessment in the expansion cohort.

Dysmorphic Facial Features VERY_FREQUENT Abnormal facial shape HP:0001999

Severity: MILD

Frequency band from PMID:33522091, in which mild dysmorphic features were present in all 20 individuals with available dysmorphology assessment (20/20 -> VERY_FREQUENT); the same paper reports 20/26 (77%) over the whole cohort including individuals not assessed, and the founding cohort reported 9/10.

Show evidence (2 references)

PMID:33522091 SUPPORT Human Clinical

"mild dysmorphic features were identified in all available subjects (20/20 individuals)"

Supplies the 20/20 denominator for the VERY_FREQUENT band and establishes that the dysmorphism is mild.

PMID:28942966 SUPPORT Human Clinical

"who manifest variable degrees of developmental delay/intellectual disability (10/10), speech delay (10/10), postnatal microcephaly (7/9), and dysmorphic features (9/10)"

Dysmorphic features in 9/10 of the founding cohort.

Bulbous Nasal Tip FREQUENT Bulbous nose HP:0000414

Frequency band from PMID:33522091, in which nasal abnormalities as a group (prominent nasal tip, bulbous nasal tip, prominent nasal bridge) were present in 9/20 (45%) -> FREQUENT. The individual nasal features are not separately enumerated, so this band applies to the nasal-abnormality group rather than to bulbous nasal tip alone.

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"Commonly identified features included a number of nasal abnormalities (prominent nasal tip, bulbous nasal tip, and prominent nasal bridge) in 9/20 (45%) individuals"

Names bulbous nasal tip among the recurrent nasal features and supplies the 45% group denominator.

Pointed Chin HP:0000307

Frequency omitted: PMID:33522091 documents pointed chin only in the photograph legend, without a numerator/denominator, so no band can be derived.

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"bulbous nasal tip (a, d, h, k, m, n), and pointed chin (a, c, d, e, f, i, k, m, n)"

Clinical photograph annotation documenting pointed chin across multiple individuals.

Limbs 1

Sandal Gap HP:0001852

Frequency omitted: PMID:33522091 reports a raw count of five individuals within the subgroup of 13 with skeletal abnormalities, without a whole-cohort denominator.

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"Note the presence of fifth finger clinodactyly (d), sandal gap deformity (i, k) and cutaneous syndactyly (j, k)"

Clinical photograph annotation documenting sandal gap in the cohort.

Musculoskeletal 3

Hypotonia FREQUENT HP:0001252

Frequency band from PMID:33522091 (hypotonia 10/26, 38% -> FREQUENT); the pooled table in PMID:36153657 reports 15/38 (39%), concordant.

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"Common features included DD and/or ID (23/26, 88%), speech delay (22/26, 85%), head circumference less than the third percentile for age (11/26, 42%), motor delay (18/26, 69%), hypotonia (10/26, 38%), and dysmorphic features (20/26, 77%)."

Hypotonia in 10/26 (38%), mapping to FREQUENT.

Scoliosis OCCASIONAL HP:0002650

Band derived conservatively: PMID:33522091 reports 5/13 (38.5%) of the skeletal-abnormality subgroup, which corresponds to 5/26 (19%) of the whole cohort. The whole-cohort denominator is the appropriate one for a disease-level frequency, giving OCCASIONAL (5-29%).

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"These included the presence of scoliosis in five individuals (5/13, 38.5%)"

Supplies the scoliosis count within the skeletal-abnormality subgroup of the 26-individual cohort.

Delayed Bone Age Delayed skeletal maturation HP:0002750

Frequency omitted: only two individuals, reported as a raw count within the skeletal-abnormality subgroup of PMID:33522091.

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"and delayed bone age in two individuals (2/13, 15%)"

Documents delayed skeletal maturation in the cohort.

Nervous System 6

Global Developmental Delay VERY_FREQUENT HP:0001263

Frequency band from PMID:33522091 (DD and/or ID 23/26, 88% -> VERY_FREQUENT); the founding cohort reported 10/10, and the pooled 38-case table in PMID:36153657 gives 34/38 (89%), all concordant.

Show evidence (2 references)

PMID:33522091 SUPPORT Human Clinical

"Common features included DD and/or ID (23/26, 88%), speech delay (22/26, 85%), head circumference less than the third percentile for age (11/26, 42%), motor delay (18/26, 69%), hypotonia (10/26, 38%), and dysmorphic features (20/26, 77%)."

Supplies both the association and the 88% denominator underpinning the VERY_FREQUENT band.

PMID:28942966 SUPPORT Human Clinical

"who manifest variable degrees of developmental delay/intellectual disability (10/10), speech delay (10/10), postnatal microcephaly (7/9), and dysmorphic features (9/10)"

Founding cohort: developmental delay/intellectual disability in all ten individuals.

Intellectual Disability VERY_FREQUENT HP:0001249

Reported jointly with developmental delay as "DD and/or ID" (23/26, 88%) in PMID:33522091; the composite denominator is the basis for the band. No published series enumerates intellectual disability separately from developmental delay.

Show evidence (2 references)

PMID:33522091 SUPPORT Human Clinical

"Common features included DD and/or ID (23/26, 88%), speech delay (22/26, 85%), head circumference less than the third percentile for age (11/26, 42%), motor delay (18/26, 69%), hypotonia (10/26, 38%), and dysmorphic features (20/26, 77%)."

Provides the composite DD/ID fraction.

PMID:40415676 SUPPORT Human Clinical

"We suggest that distal limb abnormalities associated with the BPTF gene may accompany a more severe diagnosis of intellectual disability."

Proposes an intra-syndromic severity correlation; a four-case series, so recorded as PARTIAL rather than SUPPORT.

Delayed Speech and Language Development VERY_FREQUENT HP:0000750

Frequency band from PMID:33522091 (speech delay 22/26, 85% -> VERY_FREQUENT); the founding cohort reported 10/10 and the pooled 38-case table in PMID:36153657 gives 33/38 (87%).

Show evidence (2 references)

PMID:28942966 SUPPORT Human Clinical

"who manifest variable degrees of developmental delay/intellectual disability (10/10), speech delay (10/10), postnatal microcephaly (7/9), and dysmorphic features (9/10)"

Speech delay in 10/10 of the founding cohort.

PMID:33522091 SUPPORT Human Clinical

"Common features included DD and/or ID (23/26, 88%), speech delay (22/26, 85%), head circumference less than the third percentile for age (11/26, 42%), motor delay (18/26, 69%), hypotonia (10/26, 38%), and dysmorphic features (20/26, 77%)."

Supplies the 85% denominator for the VERY_FREQUENT band.

Motor Delay FREQUENT HP:0001270

Frequency band from PMID:33522091 (motor delay 18/26, 69% -> FREQUENT); the pooled table in PMID:36153657 reports 68%, concordant.

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"Common features included DD and/or ID (23/26, 88%), speech delay (22/26, 85%), head circumference less than the third percentile for age (11/26, 42%), motor delay (18/26, 69%), hypotonia (10/26, 38%), and dysmorphic features (20/26, 77%)."

Motor delay in 18/26 (69%) of the expansion cohort, mapping to FREQUENT.

Epilepsy OCCASIONAL Seizure HP:0001250

Onset: CHILDHOOD

Frequency band from PMID:38936258, which reports early-childhood-onset epilepsy in 19% of subjects -> OCCASIONAL (5-29%). PMID:33522091 independently identified 6/26 individuals with clinical seizures and/or abnormal EEG, consistent with the same band.

Show evidence (2 references)

PMID:38936258 SUPPORT Human Clinical

"Early-childhood-onset epilepsy occurs in 19% of subjects, all presenting with a well-organized EEG background associated with generalized interictal epileptiform abnormalities in half of these cases. Drug resistance is rare."

Supplies both the 19% frequency underpinning the OCCASIONAL band and the electroclinical characterization.

PMID:33522091 SUPPORT Human Clinical

"Here, however, we identified six individuals with a history of clinical seizures and/or abnormal electroencephalograms (manuscript in preparation)."

Independent cohort confirming seizures as part of the NEDDFL spectrum and noting they were previously unreported.

EEG Abnormality HP:0002353

Frequency omitted: the denominator (11 individuals) is an epilepsy-ascertained series, not an unselected NEDDFL cohort, so a population band cannot be derived.

Show evidence (1 reference)

PMID:38936258 SUPPORT Human Clinical

"Eight individuals had epilepsy, one had a single unprovoked seizure, and two showed IEDs only."

Documents isolated interictal epileptiform discharges as a distinct electrographic finding.

Growth 2

Short Stature FREQUENT HP:0004322

Frequency band from PMID:36153657, which states in its abstract that about 35% of patients have short stature -> FREQUENT. PMID:33522091 independently reports 5/20 (25%) at last assessment, which would map to OCCASIONAL; the larger pooled denominator behind the 35% figure is preferred, and the discrepancy is recorded here rather than hidden.

Show evidence (2 references)

PMID:36153657 SUPPORT Human Clinical

"About 35% of the patients had short stature, but there had no reports published on the treatment."

Explicit 35% short-stature frequency supporting the FREQUENT band.

PMID:33522091 SUPPORT Human Clinical

"At the time of their most recent clinical assessment, 5/20 (25%) individuals exhibited short stature for age and 10/19 (53%) individuals had decreased weight for age"

Independent cohort estimate of 25%, lower than the pooled 35%; recorded as PARTIAL because it supports the association but a different band.

Poor Weight Gain and Malnutrition FREQUENT Failure to thrive HP:0001508

Frequency band from PMID:33522091 (decreased weight for age 10/19, 53% -> FREQUENT); the pooled table in PMID:36153657 reports moderate/severe malnutrition in 18/33 (55%), concordant.

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"At the time of their most recent clinical assessment, 5/20 (25%) individuals exhibited short stature for age and 10/19 (53%) individuals had decreased weight for age"

Quantifies decreased weight for age at 10/19 (53%), mapping to FREQUENT.

Other 7

Structural Brain Abnormality FREQUENT Abnormal brain morphology HP:0012443

Severity: MILD

Frequency band from PMID:33522091 (5/13 imaged individuals, 38% -> FREQUENT); the pooled table in PMID:36153657 reports brain anomalies in 11/22 (50%). Both denominators are restricted to individuals who underwent imaging, which was itself indication-driven, so the band is likely inflated relative to the whole NEDDFL population.

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"Magnetic resonance imaging (MRI) studies were obtained for 13/26 patients and were found to be normal in 8/13 cases. The remaining five studies demonstrated mild structural abnormalities only"

Establishes that brain abnormalities, when present, are mild, that most imaged individuals are normal, and supplies the 5/13 denominator.

Prominent Nasal Bridge FREQUENT HP:0000426

Same 9/20 (45%) nasal-abnormality group denominator from PMID:33522091 as the bulbous nasal tip entry; the individual features are not separately enumerated.

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"Commonly identified features included a number of nasal abnormalities (prominent nasal tip, bulbous nasal tip, and prominent nasal bridge) in 9/20 (45%) individuals"

Names prominent nasal bridge among the recurrent nasal features.

Distal Limb Anomalies FREQUENT Abnormal digit morphology HP:0011297

Frequency band from PMID:33522091, which reports skeletal abnormalities in 50% (13/26) of the cohort -> FREQUENT. That denominator covers all skeletal findings (scoliosis and delayed bone age as well as distal limb anomalies); the pooled table in PMID:36153657 gives a higher 23/28 (82%) for skeletal abnormalities, but on a partial denominator, so the more conservative whole-cohort 50% is used. The individual distal-limb findings are curated as separate phenotypes below without bands, because they are reported only as raw counts within the skeletal-abnormality subgroup. Term-binding note: this is a deliberately group-level record, so it binds the parent term HP:0011297 Abnormal digit morphology rather than the specific HP:0010621 Cutaneous syndactyly of toes. Binding a specific child while carrying a frequency derived from an all-skeletal-findings denominator would over-claim that 50% of individuals have toe syndactyly specifically. The specific findings are curated separately below (Sandal Gap, Fifth-Finger Clinodactyly) and alongside (Scoliosis, Delayed Bone Age), so no specificity is lost.

Show evidence (3 references)

PMID:33522091 SUPPORT Human Clinical

"we also identified the presence of skeletal abnormalities in 50% (13/26) of individuals"

Supplies the whole-cohort skeletal-abnormality fraction underpinning the FREQUENT band.

PMID:33522091 SUPPORT Human Clinical

"In addition to DDs, microcephaly, and distal limb defects, our cohort exhibited an increased frequency of ophthalmologic abnormalities, poor weight gain/poor feeding, and cutaneous syndactyly of the toes."

Names cutaneous syndactyly of the toes as a recurrent distal limb finding.

PMID:40415676 SUPPORT Human Clinical

"Additionally, all four of our cases in this study had distal limb abnormalities such as syndactyly and clinodactyly that accompany severe intellectual disability."

Independent series confirming syndactyly and clinodactyly as the characteristic distal limb anomalies.

Fifth-Finger Clinodactyly Clinodactyly of the 5th finger HP:0004209

Frequency omitted: documented in PMID:33522091 only as a photograph annotation without a denominator, and in PMID:40415676 in all four cases of a small ascertained series.

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"Note the presence of fifth finger clinodactyly (d), sandal gap deformity (i, k) and cutaneous syndactyly (j, k)"

Clinical photograph annotation documenting fifth-finger clinodactyly.

Cyclical Vomiting Syndrome OCCASIONAL Episodic vomiting HP:0002572

Temporal: RECURRENT

Frequency band from PMID:40614698: 3/15 (20%) met full ICHD-3 CVS criteria -> OCCASIONAL (5-29%). The band uses the strict diagnostic denominator; if partial criteria are included the fraction rises to 7/15 (47%), which would be FREQUENT. The conservative strict-criteria band is recorded here. Note also that the series was recruited with a focus on gastrointestinal symptoms, so ascertainment may inflate the fraction.

Show evidence (2 references)

PMID:40614698 SUPPORT Human Clinical

"We enrolled 15 individuals with likely pathogenic/pathogenic BPTF variants (median age: 8.8 years). Three individuals (20%) were diagnosed with CVS, and an additional four individuals (26.7%) met at least three of the ICHD-3 criteria for CVS."

Supplies the 20% strict-criteria frequency underpinning the OCCASIONAL band.

PMID:40614698 SUPPORT Human Clinical

"This study broadens the syndromic phenotype associated with BPTF haploinsufficiency, highlighting CVS as a core feature."

Establishes cyclical vomiting as part of the BPTF haploinsufficiency phenotype rather than an incidental comorbidity.

Ophthalmologic Abnormalities FREQUENT Abnormality of the eye HP:0000478

Severity: MILD

Frequency band from PMID:33522091, which identified mild ophthalmologic abnormalities in 13 of the 26-individual cohort (50% -> FREQUENT); the pooled table in PMID:36153657 reports 17/30 (57%), concordant. Term-binding note: the 50% denominator counts all ophthalmologic abnormalities, not strabismus specifically (the same 13 individuals split into exotropia in six, other strabismus in two, and myopia in three), so this group-level record binds the parent HP:0000478 Abnormality of the eye rather than HP:0000486 Strabismus. Binding Strabismus here would assert a 50% strabismus frequency the source does not support. Exotropia and Myopia are curated as separate specific phenotypes below.

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"Interestingly, 13 individuals demonstrated mild ophthalmologic abnormalities. These included the finding of exotropia in six individuals, strabismus in two individuals, and confirmed myopia in three individuals."

Supplies the 13/26 denominator and breaks the ophthalmologic group down into exotropia, strabismus, and myopia.

Exotropia HP:0000577

Frequency omitted: reported as a raw count of six individuals in PMID:33522091, but the number of individuals who actually underwent ophthalmologic assessment is not stated, so the denominator is ambiguous.

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"Interestingly, 13 individuals demonstrated mild ophthalmologic abnormalities. These included the finding of exotropia in six individuals, strabismus in two individuals, and confirmed myopia in three individuals."

Documents exotropia as the most common specific ophthalmologic finding.

🧬

Genetic Associations

1

BPTF (Heterozygous loss-of-function variants in BPTF (17q24.2) are the sole known cause of NEDDFL, acting through an autosomal dominant, haploinsufficiency mechanism. The reported allelic spectrum is dominated by truncating/null alleles (frameshift, nonsense, splice-site, whole-gene and single-exon copy-number deletions, and a translocation disrupting the gene); a minority of missense alleles has been reported, historically associated with milder phenotypes although recent reports include severely affected missense carriers.)

Gene: BPTF hgnc:3581 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (3 references)

PMID:28942966 SUPPORT Human Clinical

"we report eight loss-of-function and two missense variants (eight de novo and two of unknown origin) in BPTF on 17q24.2"

Establishes BPTF at 17q24.2 as the causative locus and shows the loss-of-function-dominant allelic spectrum.

PMID:33522091 SUPPORT Human Clinical

"Our analysis identified 20 novel, distinct variants in BPTF (Table 1) distributed throughout the gene (Figure 1), including 14 de novo and four inherited."

Confirms the absence of a mutational hotspot and quantifies the de novo versus inherited split.

PMID:40415676 SUPPORT Human Clinical

"We detected two novel missense variants in patients presenting all phenotypic characteristics of the BPTF-related NEDDFL syndrome severely, including severe ID, distinctive facial features, and anomalies of the hands and feet."

Qualifies the historical assumption that missense alleles are uniformly mild; this is a small four-case series, hence PARTIAL.

💊

Medical Actions

5

Supportive and Developmental Therapy

Category: Therapeutic Action: supportive care Ontology label: Supportive Care NCIT:C15747

There is no disease-modifying therapy for NEDDFL. Management is supportive and centres on early intervention: speech and language therapy (given the disproportionate speech delay), physical and occupational therapy for motor delay and hypotonia, educational support, nutritional support for poor weight gain and feeding difficulty, and periodic monitoring for scoliosis and ophthalmologic problems.

Target Phenotypes: Delayed speech and language development HP:0000750 Motor delay HP:0001270

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"While it is unclear how significant the degree of scoliosis was within individuals, careful examination and monitoring for this clinical finding are also recommended."

Supports the surveillance component of supportive management. No trial evidence exists for developmental therapy in NEDDFL specifically, so this is recorded as PARTIAL.

Recombinant Human Growth Hormone

Category: Therapeutic Action: Pharmacotherapy NCIT:C15986

Agent: recombinant human growth hormone (somatropin) NCIT:C837

Recombinant human growth hormone (somatropin, rhGH) has been used in NEDDFL children with short stature and documented growth hormone deficiency on arginine and levodopa stimulation testing. In the first reported use, one child gained 25.6 cm (+1.63 SD) over 3.5 years of treatment. Evidence is limited to two uncontrolled case reports and rhGH should not be regarded as an established standard of care in NEDDFL.

Target Phenotypes: Short stature HP:0004322

Show evidence (2 references)

PMID:36153657 SUPPORT Human Clinical

"Both children had short stature and responded to recombinant human growth hormone (rhGH) treatment - the first report of this therapy in NEDDFL patients."

First and, to date, principal report of growth hormone therapy in NEDDFL.

PMID:36153657 SUPPORT Human Clinical

"The salutary effect of rhGH in the NEDDFL is documented."

Authors' summary conclusion; PARTIAL because the evidence base is two uncontrolled cases with no comparator.

Antiseizure Medication

Category: Therapeutic Action: Pharmacotherapy NCIT:C15986

Agent: levetiracetam CHEBI:6437

Levetiracetam is the most widely used antiseizure medication in BPTF-related epilepsy and reduced seizure frequency in two-thirds of treated individuals. Drug-resistant epilepsy is uncommon (27% of those with epilepsy); other agents used in the reported series include sodium valproate and lamotrigine, and one individual required vagal nerve stimulator placement.

Target Phenotypes: Seizure HP:0001250

Show evidence (1 reference)

PMID:38936258 SUPPORT Human Clinical

"Levetiracetam was widely used and reduced seizure frequency in 67% of the cases."

Direct evidence of levetiracetam effectiveness in BPTF-related epilepsy.

Cyclical Vomiting Syndrome Therapy

Category: Therapeutic Action: Pharmacotherapy NCIT:C15986

Agent: ondansetron CHEBI:7773 cyproheptadine CHEBI:4046

Acute treatment of cyclical vomiting episodes with ondansetron or domperidone, and prophylaxis with cyproheptadine, domperidone, or levetiracetam combined with lamotrigine, were all associated with clinical benefit in the reported BPTF series. Evidence is observational and from a single 15-individual questionnaire study.

Target Phenotypes: Episodic vomiting HP:0002572

Show evidence (1 reference)

PMID:40614698 SUPPORT Human Clinical

"Acute therapy (ondansetron or domperidone) was administered in 42.8% of cases, and prophylactic therapy was provided in 57.1% of cases with cyproheptadine, levetiracetam combined with lamotrigine, and domperidone; all therapies were associated with clinical benefit."

Observational report of benefit from acute and prophylactic CVS therapy; uncontrolled, hence PARTIAL.

Genetic Counseling

Category: Counseling / Informational Action: genetic counseling Ontology label: Genetic Counseling NCIT:C15240

Genetic counseling should address the autosomal dominant inheritance, the 50% recurrence risk for an affected parent, the possibility that an apparently de novo variant is inherited from a mildly affected parent (four such families are documented), the residual recurrence risk from parental germline mosaicism after an apparently de novo variant, and the variable expressivity of the disorder.

Show evidence (1 reference)

PMID:33522091 SUPPORT Human Clinical

"Our study has also uncovered four cases of inherited BPTF variants, providing some insight into the penetrance and expressivity of NEDDFL."

Documented inherited variants are the basis for counseling about parental testing and recurrence risk.

🔬

Diagnosis

3

Trio Exome or Genome Sequencing

First-line testing for unexplained syndromic developmental delay or intellectual disability. Trio exome sequencing (or genome sequencing, which combines sequence and structural-variant detection) with copy-number calling is the highest-yield route to a NEDDFL diagnosis, and is how most reported individuals were ascertained. Trio design matters here because the majority of pathogenic BPTF variants are de novo, and parental testing is what distinguishes a de novo variant from the transmitted alleles documented in four families.

whole exome sequencing NCIT:C101295

Show evidence (3 references)

PMID:33522091 SUPPORT Human Clinical

"Molecular testing results from exome sequencing, chromosomal microarray, or next‐generation sequencing panel were submitted by patients' healthcare providers"

Documents the diagnostic modalities through which the 26-individual expansion cohort was actually ascertained.

PMID:40415676 SUPPORT Human Clinical

"BPTF gene variants were detected using whole-exome sequencing. Family segregation analysis was performed using sanger sequencing."

Independent series confirming exome sequencing as the detection method, with Sanger segregation analysis in the family.

PMID:36153657 SUPPORT Human Clinical

"The exome sequencing was performed in two probands. Sanger sequencing was used to confirm the identified variants both in probands and their parents."

Shows the standard workflow of exome discovery plus Sanger confirmation in proband and parents.

Chromosomal Microarray for 17q24.2 Copy-Number Variants

Chromosomal microarray remains informative because a meaningful share of the reported allelic spectrum is copy-number: single-exon and whole-gene BPTF deletions, larger 17q24.2 deletions, and a chromosomal translocation disrupting the gene. Microarray was part of the ascertainment of the founding and expansion cohorts. A larger 17q24.2 deletion should be interpreted as a potential contiguous-gene event rather than attributed to BPTF alone.

chromosomal microarray (array comparative genomic hybridization) NCIT:C18084

Show evidence (2 references)

PMID:28942966 SUPPORT Human Clinical

"we report eight loss-of-function and two missense variants (eight de novo and two of unknown origin) in BPTF on 17q24.2"

Establishes the 17q24.2 locus that copy-number testing must cover.

PMID:33522091 SUPPORT Human Clinical

"Molecular testing results from exome sequencing, chromosomal microarray, or next‐generation sequencing panel were submitted by patients' healthcare providers"

Confirms chromosomal microarray as one of the modalities that identified individuals in the expansion cohort.

ACMG/AMP Variant Interpretation with Parental Testing

Diagnosis requires a compatible phenotype plus a BPTF variant classified under ACMG/AMP criteria, supported by parental testing, phenotype match, population frequency, and predicted loss of function. In the expansion cohort, 20 variants were classified as 11 pathogenic, 7 likely pathogenic, and 2 VUS. Truncating and copy-number alleles are straightforward because loss of function is the established mechanism; missense alleles are the hard case and a missense VUS alone does not establish the diagnosis. That caution is not merely theoretical: severely affected missense carriers have since been reported (PMID:40415676), so a missense VUS can be neither dismissed nor accepted on phenotype severity alone.

genetic testing NCIT:C15709

Explicit negatives, recorded so their absence is not mistaken for a curation gap. (1) There are no formal consensus diagnostic criteria for NEDDFL; diagnosis is a compatible phenotype plus molecular confirmation. (2) There is no diagnostic biochemical, enzymatic, imaging, or circulating biomarker - a normal brain MRI in particular does not exclude the diagnosis, since most imaged individuals in the expansion cohort had normal studies. (3) No validated functional assay and no DNA-methylation episignature has been established for BPTF, despite NEDDFL being a chromatinopathy where an episignature might be expected; RNA sequencing and proteomics for resolving difficult variants remain investigational. (4) No newborn or general population screening exists; cascade testing is appropriate once a familial pathogenic variant is known.

Show evidence (2 references)

PMID:33522091 SUPPORT Human Clinical

"Variants were interpreted as pathogenic (11), likely pathogenic (7), or VUS (2) based on the current ACMG criteria."

Documents ACMG/AMP classification as the interpretation framework and the residual VUS rate.

PMID:33522091 SUPPORT Human Clinical

"it is anticipated that the finding of missense variants in BPTF may present a diagnostic challenge for practitioners, particularly in individuals with mild phenotypes"

The authors flag missense variants as the principal interpretation difficulty, supporting the caution that a missense VUS alone is not diagnostic.

📊

Prevalence

1

Worldwide

Cases In Literature Ultra Rare

Only 36 individuals had been reported when PMID:36153657 was written (2022); subsequent series (PMID:38936258, PMID:40614698, PMID:40415676) have added further individuals, but the total remains in the low hundreds at most. No population-based prevalence estimate exists.

Show evidence (2 references)

PMID:36153657 SUPPORT Human Clinical

"To date, there are only 36 cases reported in the literature, and patients mainly presented with a developmental delay, language delay, and microcephaly."

Provides the published case count underpinning the ultra-rare classification.

PMID:40415676 SUPPORT Human Clinical

"Neurodevelopmental disorder with dysmorphic facies and distal limb anomalies (NEDDFL, OMIM no #617755) is an ultra-rare syndrome associated with heterozygous pathogenic variants in the BPTF gene."

Independent characterization of the disorder as ultra-rare.

🔀

Differential Diagnoses

3

Conditions with similar clinical presentations that must be differentiated from BPTF-Related Neurodevelopmental Disorder:

Neurodevelopmental disorder with dysmorphic facies and distal skeletal anomalies (ZMIZ1) MONDO:0032855

Overlapping Features A separate autosomal dominant neurodevelopmental entity caused by heterozygous ZMIZ1 variants. Its MONDO label differs from this disorder's by a single word ("skeletal" versus "limb"), which makes it the single highest named-entity-confusion risk for NEDDFL in any label- or text-based search.

Distinguishing Features

Molecular: ZMIZ1 versus BPTF (hgnc:3581). The gene is the only reliable discriminator; confirm the causative gene before importing any cohort data published under either "dysmorphic facies and distal ... anomalies" phrasing.
Nomenclature: the near-identical labels are the hazard, not the phenotypes. Both are dominant neurodevelopmental syndromes with dysmorphism and distal appendicular findings.

Silver-Russell syndrome

Overlapping Features A clinical phenocopy hazard rather than a nomenclature hazard: the combination of small-for-gestational-age birth, poor postnatal growth, a small triangular face, and feeding difficulty can prompt an initial diagnosis of Silver-Russell syndrome in a child later found to have BPTF disruption. At least one adult carried the Silver-Russell label for 35 years before BPTF disruption was identified.

Distinguishing Features

NEDDFL has postnatal (secondary) microcephaly, whereas relative macrocephaly for body size is characteristic of Silver-Russell syndrome.
NEDDFL has prominent speech delay and intellectual disability; cognition is typically preserved or only mildly affected in Silver-Russell syndrome.
Silver-Russell syndrome is most often caused by 11p15 loss of methylation or maternal uniparental disomy of chromosome 7, neither of which involves BPTF.

🐁

Animal Models

3

Bptf forebrain-conditional knockout mouse Conditional knockout mouse model of NEDDFL

Forebrain-specific Bptf knockout mice, generated explicitly to model NEDDFL (PMID:35604347). They are born at normal Mendelian ratios and survive to adulthood but are smaller, with severe cortical hypoplasia, prolonged progenitor cell cycle length, increased cell death, disrupted cortical lamination with reduced deep-layer neurons, and impaired acquisition of distinct neuronal fates.

Species

Mus musculus

Genotype

Emx1-Cre forebrain-conditional Bptf knockout (Bptf cKO)

Pathograph links

Neural Progenitor Cell-Cycle Prolongation and Apoptosis recapitulates The model directly demonstrates the cellular mechanism this node asserts: prolonged progenitor cell cycle length and increased programmed cell death reducing neuronal output from the progenitor pool.

Readouts

Progenitor cell cycle length

Cell cycle length of cortical neural progenitors in Bptf cKO versus littermate control forebrain.

Direction: INCREASED

Interpretation: Lengthened cycle time is the measured basis for the reduced neuronal output asserted by this node.

Progenitor cell death incidence

Incidence of programmed cell death among cortical progenitors in Bptf cKO versus control.

apoptotic process GO:0006915

Direction: INCREASED

Interpretation: Raised cell death compounds the cycle-length effect in depleting the progenitor pool.

Show evidence (1 reference)

PMID:35604347 SUPPORT Model Organism

"Prolonged progenitor cell cycle length and a high incidence of cell death reduced the neuronal output."

States the progenitor cell-cycle and apoptosis phenotype that this node asserts.

Cortical Hypoplasia and Disrupted Lamination recapitulates fidelity: moderate Reproduces both facets of the node: severe cortical hypoplasia, and disrupted lamination with reduced deep-layer neurons and impaired acquisition of distinct cortical cell fates.

Limitations: The model is a homozygous conditional null restricted to the forebrain, not a heterozygous haploinsufficiency model, and heterozygous animals were reported to have little to no phenotype. Its severe cortical hypoplasia is therefore a complete-loss phenotype whose quantitative relationship to the human half-dosage disease is unresolved. This is the substance of the `bptf_mouse_homozygous_vs_human_haploinsufficiency` HUMAN_MODEL_MISMATCH discussion, which attaches to this same node.

Readouts

Deep-layer neuron proportion

Proportion of deep-layer neurons within the cortical plate of Bptf cKO versus control.

Direction: DECREASED

Interpretation: A reduced deep-layer fraction is the quantitative signature of the disrupted lamination this node asserts.

Ctip2-positive neuronal fate acquisition

Acquisition of distinct cortical identities, indexed by Ctip2-positive neurons, in Bptf cKO versus control.

cerebral cortex neuron differentiation GO:0021895

Direction: DECREASED

Interpretation: Impaired fate acquisition distinguishes a maturation defect from simple cell loss.

Show evidence (1 reference)

PMID:35604347 SUPPORT Model Organism

"Cortical lamination was also disrupted with reduced proportions of deep layer neurons, and neuronal maturation defects that impaired the acquisition of distinct cell fates"

Documents the laminar and cell-fate facets of the node that the model reproduces.

Interpretive caveat beyond the per-link limitations: ablation of Smarca1 (the SNF2L ATPase partner of BPTF within NURF) produces mice with ENLARGED brains, the direct contrast of the NEDDFL microcephaly, so the two NURF subunits cannot be treated as interchangeable when modelling this disorder. That discordance is the basis of the `bptf_vs_smarca1_dosage_paradox` knowledge gap.

Show evidence (2 references)

PMID:35604347 SUPPORT Model Organism

"To model the NEDDFL syndrome, we generated forebrain-specific Bptf knockout (Bptf conditional Knockout (cKO)) mice."

Establishes the model's purpose and construction.

PMID:35604347 SUPPORT Model Organism

"Surprisingly, ablation of Smarca1 resulted in mice with enlarged brains, a direct contrast to the phenotype of NEDDFL patients."

Records the SMARCA1 discordance that limits inference from NURF ATPase knockouts to BPTF haploinsufficiency.

bptf CRISPR F0 crispant zebrafish CRISPR F0 knockout zebrafish model

CRISPR-Cas9 knockout of zebrafish bptf produces F0 mutant larvae with significantly reduced head size, increased apoptosis by TUNEL staining, and a substantially increased ceratohyal angle indicating abnormal craniofacial patterning (PMID:28942966). This model recapitulates both the microcephaly and the craniofacial dimensions of NEDDFL.

Species

Danio rerio

Genotype

CRISPR-Cas9 bptf F0 crispant

Pathograph links

Postnatal Microcephaly and Growth Restriction partially recapitulates fidelity: moderate Reduced head size in bptf F0 larvae is the cross-species correlate of the human microcephaly.

Limitations: Only partially recapitulates the human node. The zebrafish readout is larval head size in a complete loss-of-function crispant, so it captures reduced brain growth but not the defining postnatal (secondary) timing of the human microcephaly, and it says nothing about the accompanying somatic growth restriction, short stature, or growth hormone deficiency.

Readouts

Larval head size

Head size of bptf F0 crispant larvae versus control larvae.

Direction: DECREASED

Interpretation: Significantly reduced head size is the model's microcephaly readout; it indexes reduced brain growth but not the postnatal timing of the human phenotype.

Show evidence (1 reference)

PMID:28942966 SUPPORT Model Organism

"Using CRISPR-Cas9 genome editing of bptf in zebrafish to induce a loss of gene function, we observed a significant reduction in head size of F0 mutants compared to control larvae."

Reduced head size is the model's microcephaly readout; PARTIAL because larval head size does not capture the postnatal timing or the somatic growth arm of the human node.

Disrupted Craniofacial and Limb Patterning recapitulates Increased ceratohyal angle is an established quantitative readout of disrupted craniofacial patterning, and is the direct experimental support for the craniofacial arm of this node.

Limitations: Supports the craniofacial arm only. No model has yet demonstrated the distal limb arm of this node, which is why the node is marked PROVISIONAL.

Readouts

Ceratohyal angle

Angle of the ceratohyal cartilage of the craniofacial skeleton in bptf F0 crispants versus controls.

Direction: INCREASED

Interpretation: A substantially widened ceratohyal angle is the established quantitative index of abnormal craniofacial patterning in zebrafish.

Show evidence (1 reference)

PMID:28942966 SUPPORT Model Organism

"we observed a substantial increase of the ceratohyal angle of the craniofacial skeleton in bptf F0 mutants, indicating abnormal craniofacial patterning"

Direct experimental demonstration of disrupted craniofacial patterning on bptf loss.

Show evidence (1 reference)

PMID:28942966 SUPPORT Model Organism

"Using CRISPR-Cas9 genome editing of bptf in zebrafish to induce a loss of gene function, we observed a significant reduction in head size of F0 mutants compared to control larvae."

Establishes the zebrafish model and its microcephaly readout.

Constitutive Bptf-null mouse embryo Constitutive null mouse embryo

Constitutive Bptf mouse mutants manifest growth defects at the post-implantation stage and are resorbed by E8.5, failing to establish a functional distal visceral endoderm (PMID:18974875). This establishes Bptf as essential for early mammalian development and is the basis for the anterior-posterior axis role cited in the human disease literature.

Species

Mus musculus

Genotype

Constitutive Bptf-null (gene-trap) embryo

Pathograph links

BPTF Haploinsufficiency perturbs fidelity: low Establishes that Bptf dosage is developmentally critical in a mammal, which is the premise that makes a 50% reduction a credible human disease mechanism.

Limitations: Low fidelity to the human node. This is a constitutive homozygous null causing embryonic lethality by E8.5, two dosage steps away from the human heterozygous, viable, postnatally manifesting disorder. It demonstrates gene essentiality, not the consequences of haploinsufficiency, and no heterozygous phenotype is reported.

Readouts

Post-implantation embryonic survival

Survival of constitutive Bptf-null embryos, which show post-implantation growth defects and are resorbed by E8.5.

Direction: DECREASED

Interpretation: Complete loss is embryonic-lethal, establishing Bptf as dosage-critical; it does not measure the heterozygous state this node describes.

Show evidence (1 reference)

PMID:18974875 SUPPORT Model Organism

"Bptf mutants manifest growth defects at the post-implantation stage and are reabsorbed by E8.5."

Demonstrates embryonic essentiality of Bptf; PARTIAL with respect to the haploinsufficiency node because the genotype is a homozygous null.

Show evidence (1 reference)

PMID:18974875 SUPPORT Model Organism

"Bptf mutants manifest growth defects at the post-implantation stage and are reabsorbed by E8.5."

Establishes the embryonic essentiality of Bptf that makes heterozygous dosage reduction plausible as a human disease mechanism.

{ }

Source YAML

click to show

name: BPTF-Related Neurodevelopmental Disorder
creation_date: "2026-08-15T00:00:00Z"
category: Mendelian
synonyms:
- NEDDFL
- neurodevelopmental disorder with dysmorphic facies and distal limb anomalies
- BPTF haploinsufficiency
description: >-
  Neurodevelopmental disorder with dysmorphic facies and distal limb anomalies
  (NEDDFL, MONDO:0060596, OMIM:617755) is an ultra-rare autosomal dominant
  syndrome caused by heterozygous loss-of-function variants in BPTF (hgnc:3581)
  at 17q24.2. BPTF encodes the bromodomain PHD finger transcription factor, the
  largest and NURF-exclusive subunit of the nucleosome remodeling factor (NURF),
  an ISWI-family ATP-dependent chromatin-remodeling complex whose catalytic
  ATPase is SNF2L/SMARCA1. BPTF reads the activating chromatin marks H3K4me3
  (via its PHD finger) and H4K16ac (via its bromodomain) and thereby couples
  those marks to ATP-dependent nucleosome sliding at developmental gene
  promoters. Because BPTF is dosage-sensitive, a single null allele is
  sufficient to produce disease. The clinical core is developmental
  delay/intellectual disability with disproportionate speech and language delay,
  postnatal (secondary) microcephaly, poor growth, a mild but recognizable
  dysmorphic facial gestalt (prominent or bulbous nasal tip, prominent nasal
  bridge, pointed chin), and mild distal limb anomalies of the hands and feet
  (cutaneous 2-3 toe syndactyly, sandal gap, fifth-finger clinodactyly).
  Phenotypic expansion since the 2017 founding cohort has added ophthalmologic
  abnormalities, scoliosis and other skeletal findings, mild structural brain
  abnormalities, early-childhood-onset epilepsy, and cyclical vomiting syndrome.
  Most variants arise de novo, but transmitted alleles from mildly affected
  parents establish variable expressivity. Management is supportive; there is no
  disease-modifying therapy.
notes: >-
  Named-entity-confusion (NEC) guardrail. This entry is anchored strictly on
  MONDO:0060596 / OMIM:617755 / BPTF (hgnc:3581), confirmed by the MONDO
  `RO:0004003` gene-association relation returned by
  `runoak -i sqlite:obo:mondo info MONDO:0060596 -O obo` (relationship:
  RO:0004003 HGNC:3581 ! BPTF; xref: OMIM:617755; xref: Orphanet:686482). NEDDFL
  sits inside a large series of near-identically-named "neurodevelopmental
  disorder with ..." OMIM entities, so every citation used here was checked to
  name BPTF specifically. Three neighbours are deliberately kept separate and
  are recorded under `differential_diagnoses`. (1) MONDO:0032855
  "neurodevelopmental disorder with dysmorphic facies and distal SKELETAL
  anomalies" (NEDDFSA, ZMIZ1, OMIM:618659) differs from this disorder's label by
  one word; it is a different gene and a different MONDO entity. (2)
  MONDO:0044319 "intellectual developmental disorder with dysmorphic facies,
  seizures and distal limb anomalies" (IDDFSDA, OTUD6B, OMIM:617452) is
  autosomal recessive and biallelic, whereas NEDDFL is autosomal dominant and
  typically de novo; the dismech OTUD6B entry carries the reciprocal guardrail
  and deliberately excludes PMID:33522091 (a NEDDFL cohort) from all of its
  claims, citing it only on its BPTF differential record. That PMID is a
  legitimate primary source here and is used extensively. (3) Silver-Russell
  syndrome has been an initial clinical diagnosis in at least one adult later
  found to have BPTF disruption (PMID:30633344), which is a phenocopy hazard
  rather than a nomenclature hazard.

  Frequency discipline. The primary band source is PMID:33522091, the
  26-individual phenotypic expansion cohort, whose reported fractions are quoted
  verbatim as evidence on each phenotype. A larger pooled table exists
  (PMID:36153657 summarises all 38 individuals reported through 2022: DD/ID
  34/38 89%, speech/language delay 33/38 87%, skeletal abnormalities 23/28 82%,
  ophthalmological anomalies 17/30 57%, malnutrition 18/33 55%, brain anomalies
  11/22 50%, microcephaly 18/37 49%, hypotonia 15/38 39%, short stature 12/34
  35%). Those pooled numbers are recorded here in prose only and are NOT used as
  evidence snippets, because the reference validator can currently verify only
  the abstract of PMID:36153657 and that table is in the article body; the one
  band that rests on PMID:36153657 (short stature, 35%) uses a sentence that is
  in its abstract. Where a feature has an explicit published percentage in a
  dedicated study (epilepsy 19% in PMID:38936258, cyclical vomiting 20% in
  PMID:40614698) that study's denominator is used. Where no usable denominator
  exists the band is omitted rather than guessed. Caveat: all denominators
  derive from small, ascertainment-biased clinical cohorts of an ultra-rare
  disorder, and several counts are reported only for the subset of individuals
  in whom the feature was assessed.

  Deep research. A Falcon (Edison Scientific) deep-research run was performed
  (research/BPTF-Related_Neurodevelopmental_Disorder-deep-research-falcon.md,
  21 citations, 5/5 verifiable references, 0% confabulation rate reported by the
  provider's own validator). Its causal model and phenotype summary agreed with
  the primary literature read independently here, and it introduced no PMID that
  is not already cited in this entry, so it was used only as corroboration. Its
  own caveat that a MONDO accession "could not be verified from the retrieved
  primary literature" is why the MONDO binding here comes from a direct OAK
  lookup rather than from the report. No GeneReviews chapter exists for BPTF or
  NEDDFL (PubMed searches for "BPTF GeneReviews" and "NEDDFL GeneReviews"
  returned no results), so the GeneReviews phenotype baseline step does not
  apply to this entry.

  Term-binding note. The supportive-care and genetic-counseling treatments use
  NCIT intervention terms (NCIT:C15747 Supportive Care, NCIT:C15240 Genetic
  Counseling) rather than the MAXO terms suggested in CLAUDE.md
  (MAXO:0000950, MAXO:0000079). MAXO terms are not reachable from the
  NCIT:C25218 root that the `TreatmentActionTerm` dynamic enum expands from and
  fail `just validate-terms-file`; the same substitution is documented in the
  Progressive_Familial_Intrahepatic_Cholestasis entry. Please do not "correct"
  these back to MAXO.
disease_term:
  preferred_term: NEDDFL
  term:
    id: MONDO:0060596
    label: neurodevelopmental disorder with dysmorphic facies and distal limb anomalies
parents:
- Mendelian neurodevelopmental disorder
- Chromatin remodeling disorder
references:
- reference: PMID:28942966
  title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
- reference: PMID:33522091
  title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
- reference: PMID:36153657
  title: "The effect of growth hormone treatment in children with novel BPTF gene variants: A report of two cases and literature review."
classifications:
  harrisons_chapter:
  - classification_value: NEUROLOGIC
    notes: >-
      The dominant clinical burden is neurodevelopmental: developmental delay,
      intellectual disability, disproportionate speech delay, hypotonia,
      microcephaly, and (in a minority) epilepsy.
    evidence:
    - reference: PMID:28942966
      reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        who manifest variable degrees of developmental delay/intellectual
        disability (10/10), speech delay (10/10), postnatal microcephaly (7/9),
        and dysmorphic features (9/10)
      explanation: >-
        The defining cohort establishes developmental delay, intellectual
        disability, and speech delay as near-universal features, supporting a
        neurologic chapter assignment.
  - classification_value: GENETICS_ENVIRONMENT_DISEASE
    notes: >-
      NEDDFL is a monogenic, dosage-sensitivity (haploinsufficiency) disorder of
      a chromatin-remodeling complex subunit.
    evidence:
    - reference: PMID:28942966
      reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        our data demonstrate the pathogenic role of BPTF haploinsufficiency in
        syndromic neurodevelopmental anomalies and extend the clinical spectrum
        of human disorders caused by ablation of chromatin remodeling complexes
      explanation: >-
        Explicitly frames the disorder as a genetic disease of chromatin
        remodeling complex dosage.

inheritance:
- name: Autosomal dominant inheritance
  inheritance_term:
    preferred_term: Autosomal dominant inheritance
    term:
      id: HP:0000006
      label: Autosomal dominant inheritance
  description: >-
    NEDDFL results from a heterozygous loss-of-function allele of BPTF; the gene
    is dosage-sensitive and a single null allele is sufficient to cause disease.
    Most reported variants arose de novo, but transmission from a mildly
    affected parent has been documented in four families, establishing autosomal
    dominant inheritance with variable expressivity rather than exclusively
    de novo occurrence. Transmitting parents range from isolated microcephaly
    without reported developmental delay, through learning disability with
    independent adult function, to a phenotype comparable to that of the
    proband. Penetrance has not been quantified.
  expressivity: VARIABLE
  evidence:
  - reference: PMID:28942966
    reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we report eight loss-of-function and two missense variants (eight de novo
      and two of unknown origin) in BPTF on 17q24.2
    explanation: >-
      Establishes heterozygous, predominantly de novo variation at a single
      locus as the molecular basis, consistent with autosomal dominant
      inheritance.
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Our study has also uncovered four cases of inherited BPTF variants,
      providing some insight into the penetrance and expressivity of NEDDFL.
    explanation: >-
      Documented parent-to-child transmission confirms dominant inheritance and
      demonstrates that the disorder is not exclusively de novo.
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The histories reported in these patients and the presence of inherited
      pathogenic variants in BPTF do suggest a pattern of variable expressivity
      in NEDDFL.
    explanation: >-
      Directly supports the recorded VARIABLE expressivity of the dominant
      allele.

genetic:
- name: BPTF
  gene_term:
    preferred_term: BPTF
    term:
      id: hgnc:3581
      label: BPTF
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  association: >-
    Heterozygous loss-of-function variants in BPTF (17q24.2) are the sole known
    cause of NEDDFL, acting through an autosomal dominant, haploinsufficiency
    mechanism. The reported allelic spectrum is dominated by truncating/null
    alleles (frameshift, nonsense, splice-site, whole-gene and single-exon
    copy-number deletions, and a translocation disrupting the gene); a minority
    of missense alleles has been reported, historically associated with milder
    phenotypes although recent reports include severely affected missense
    carriers.
  notes: >-
    `variant_origin: GERMLINE` is deliberate and covers both arms of the
    reported allelic spectrum. The majority of variants are de novo, but four
    families with transmission from a non-mosaic affected parent are documented
    (PMID:33522091 reports 14 de novo and four inherited among 20 variants), so
    tagging the gene entry `DE_NOVO` would contradict the inherited arm recorded
    in `association`, in the disease-level `inheritance` block, and in the
    Genetic Counseling treatment. GERMLINE is true of every constitutional
    variant in both arms; the de novo/inherited split is quantified with its own
    cited evidence rather than compressed into this enum.

    Variant nomenclature in the literature uses the NM_004459.6 transcript
    (some later reports use NM_182641.4). No recurrent hotspot variant has been
    described; reported variants are distributed throughout the gene. Somatic
    BPTF alterations reported in cancer biology are a distinct literature and
    must not be conflated with the constitutional disorder.
  evidence:
  - reference: PMID:28942966
    reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we report eight loss-of-function and two missense variants (eight de novo
      and two of unknown origin) in BPTF on 17q24.2
    explanation: >-
      Establishes BPTF at 17q24.2 as the causative locus and shows the
      loss-of-function-dominant allelic spectrum.
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Our analysis identified 20 novel, distinct variants in BPTF (Table 1)
      distributed throughout the gene (Figure 1), including 14 de novo and four
      inherited.
    explanation: >-
      Confirms the absence of a mutational hotspot and quantifies the de novo
      versus inherited split.
  - reference: PMID:40415676
    reference_title: "Effects of the Missense Variants on Complete Phenotype and Splicing Variant on Severe Growth Retardation in the BPTF Gene."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We detected two novel missense variants in patients presenting all
      phenotypic characteristics of the BPTF-related NEDDFL syndrome severely,
      including severe ID, distinctive facial features, and anomalies of the
      hands and feet.
    explanation: >-
      Qualifies the historical assumption that missense alleles are uniformly
      mild; this is a small four-case series, hence PARTIAL.

prevalence:
- population: Worldwide
  measure_type: CASES_IN_LITERATURE
  prevalence_class: ULTRA_RARE
  notes: >-
    Only 36 individuals had been reported when PMID:36153657 was written (2022);
    subsequent series (PMID:38936258, PMID:40614698, PMID:40415676) have added
    further individuals, but the total remains in the low hundreds at most. No
    population-based prevalence estimate exists.
  evidence:
  - reference: PMID:36153657
    reference_title: "The effect of growth hormone treatment in children with novel BPTF gene variants: A report of two cases and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      To date, there are only 36 cases reported in the literature, and patients
      mainly presented with a developmental delay, language delay, and
      microcephaly.
    explanation: >-
      Provides the published case count underpinning the ultra-rare
      classification.
  - reference: PMID:40415676
    reference_title: "Effects of the Missense Variants on Complete Phenotype and Splicing Variant on Severe Growth Retardation in the BPTF Gene."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Neurodevelopmental disorder with dysmorphic facies and distal limb
      anomalies (NEDDFL, OMIM no #617755) is an ultra-rare syndrome associated
      with heterozygous pathogenic variants in the BPTF gene.
    explanation: >-
      Independent characterization of the disorder as ultra-rare.

pathophysiology:
- name: BPTF Haploinsufficiency
  biological_scale: MOLECULAR
  mechanism_confidence: ESTABLISHED
  description: >-
    A heterozygous loss-of-function allele of BPTF at 17q24.2 (frameshift,
    nonsense, splice-site, exonic or whole-gene deletion, or gene-disrupting
    translocation) halves functional BPTF protein dosage. BPTF is
    dosage-sensitive: unlike many chromatin genes, one null allele produces overt
    human disease, and BPTF is the NURF-exclusive subunit, so its loss cannot be
    compensated by the other ISWI complexes that share the SNF2L/SNF2H ATPases.
  gene:
    preferred_term: BPTF
    term:
      id: hgnc:3581
      label: BPTF
  downstream:
  - target: Impaired NURF Chromatin-Remodeling Activity
    causal_link_type: DIRECT
    description: >-
      Reduced BPTF protein lowers the amount of assembled, chromatin-engaged
      NURF and its recruitment of the SNF2L ATPase to target promoters.
  evidence:
  - reference: PMID:28942966
    reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      our data demonstrate the pathogenic role of BPTF haploinsufficiency in
      syndromic neurodevelopmental anomalies and extend the clinical spectrum
      of human disorders caused by ablation of chromatin remodeling complexes
    explanation: >-
      States haploinsufficiency as the disease mechanism.
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Haploinsufficiency of BPTF in humans leads to the clinical entity known as
      neurodevelopmental disorder with dysmorphic facies and distal limb
      anomalies (NEDDFL, MIM#617755).
    explanation: >-
      Links reduced BPTF dosage directly to the named clinical entity.

- name: Impaired NURF Chromatin-Remodeling Activity
  biological_scale: MOLECULAR
  mechanism_confidence: ESTABLISHED
  description: >-
    BPTF is the largest subunit of NURF, an ISWI-family ATP-dependent
    chromatin-remodeling complex containing the SNF2L/SMARCA1 ATPase. BPTF reads
    active-chromatin marks - H3K4me3 through its PHD finger and H4K16ac through
    its bromodomain - and this reading is what tethers NURF to active promoters
    and delivers the SNF2L ATPase there for nucleosome sliding. When BPTF is
    reduced, NURF occupancy at H3K4me3-marked promoters falls and ATP-dependent
    nucleosome repositioning at those promoters is impaired.
  biological_processes:
  - preferred_term: ATP-dependent chromatin remodeling
    term:
      id: GO:0006338
      label: chromatin remodeling
    modifier: DECREASED
  molecular_functions:
  - preferred_term: BPTF PHD finger reading of H3K4me3
    term:
      id: GO:0140002
      label: histone H3K4me3 reader activity
    modifier: DECREASED
  - preferred_term: NURF nucleosome sliding
    term:
      id: GO:0140750
      label: nucleosome array spacer activity
    modifier: DECREASED
  downstream:
  - target: Dysregulated Developmental Gene Transcription
    causal_link_type: DIRECT
    description: >-
      Loss of NURF-mediated nucleosome remodeling at developmental promoters
      changes the transcriptional output of those genes.
  evidence:
  - reference: PMID:28942966
    reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Bromodomain PHD finger transcription factor (BPTF) is the largest subunit
      of nucleosome remodeling factor (NURF), a member of the ISWI
      chromatin-remodeling complex.
    explanation: >-
      Establishes BPTF's identity as the largest NURF subunit within the ISWI
      family.
  - reference: PMID:16728976
    reference_title: "A PHD finger of NURF couples histone H3 lysine 4 trimethylation with chromatin remodelling."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Here we show that a plant homeodomain (PHD) finger of nucleosome
      remodelling factor (NURF), an ISWI-containing ATP-dependent
      chromatin-remodelling complex, mediates a direct preferential association
      with H3K4me3 tails.
    explanation: >-
      Defines the molecular reader function of the BPTF PHD finger that is lost
      when BPTF dosage falls.
  - reference: PMID:16728976
    reference_title: "A PHD finger of NURF couples histone H3 lysine 4 trimethylation with chromatin remodelling."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Depletion of H3K4me3 causes partial release of the NURF subunit, BPTF
      (bromodomain and PHD finger transcription factor), from chromatin and
      defective recruitment of the associated ATPase, SNF2L (also known as ISWI
      and SMARCA1), to the HOXC8 promoter.
    explanation: >-
      Demonstrates the mechanistic coupling between BPTF chromatin engagement
      and delivery of the SNF2L remodeling ATPase to a developmental promoter.
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      BPTF in particular facilitates this interaction by the preferential
      binding of its plant homeodomain (PHD) finger to the tails of the
      trimethylated lysine 4 of histone H3 (H3K4me3) and binding of its
      bromodomain to the acetylated lysine 16 of histone H4 (H4K16ac)
    explanation: >-
      Records both reader modules of BPTF in the disease-specific literature.

- name: Dysregulated Developmental Gene Transcription
  biological_scale: MOLECULAR
  mechanism_confidence: ESTABLISHED
  description: >-
    NURF target genes are enriched for developmental regulators. Loss of BPTF
    misregulates homeobox/HOX transcription factors, SMAD-pathway targets, and
    fate-determining transcription factors; dysregulated genes in the Bptf
    conditional-knockout mouse cortex are enriched for MYC binding sites, MYC
    being a known BPTF transcriptional cofactor. The consequence is not global
    transcriptional collapse but loss of correct spatial and temporal control of
    a developmental gene program.
  biological_processes:
  - preferred_term: regulation of transcription by RNA polymerase II
    term:
      id: GO:0006357
      label: regulation of transcription by RNA polymerase II
    modifier: ABNORMAL
  - preferred_term: anterior/posterior pattern specification
    term:
      id: GO:0009952
      label: anterior/posterior pattern specification
    modifier: ABNORMAL
  downstream:
  - target: Neural Progenitor Cell-Cycle Prolongation and Apoptosis
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      Misexpression of fate-determining transcription factors and
      apoptotic-signaling pathway genes impairs progenitor proliferation and
      survival.
  - target: Disrupted Craniofacial and Limb Patterning
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      Loss of correct HOX/homeobox spatial patterning perturbs craniofacial and
      distal limb morphogenesis.
  evidence:
  - reference: PMID:16728976
    reference_title: "A PHD finger of NURF couples histone H3 lysine 4 trimethylation with chromatin remodelling."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Loss of BPTF in Xenopus embryos mimics WDR5 loss-of-function phenotypes,
      and compromises spatial control of Hox gene expression.
    explanation: >-
      Directly demonstrates that BPTF loss dysregulates spatial developmental
      gene expression in a vertebrate embryo.
  - reference: PMID:18974875
    reference_title: "Essential role of chromatin remodeling protein Bptf in early mouse embryos and embryonic stem cells."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Microarray analysis at early stages of differentiation has identified
      Bptf-dependent gene targets including homeobox transcriptions factors and
      genes essential for the development of ectoderm, mesoderm, and both
      definitive and visceral endoderm.
    explanation: >-
      Identifies homeobox transcription factors and germ-layer developmental
      genes as the transcriptional targets that depend on Bptf.
  - reference: PMID:35604347
    reference_title: "Generation of a mouse model of the neurodevelopmental disorder with dysmorphic facies and distal limb anomalies syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      RNAseq and pathway analysis identified altered expression of
      fate-determining transcription factors and the biological pathways
      involved in neural development, apoptotic signaling and amino acid
      biosynthesis.
    explanation: >-
      In the disease-specific forebrain Bptf knockout, the transcriptional
      consequence is misexpression of fate-determining transcription factors and
      neural-development/apoptosis pathways.
  - reference: PMID:35604347
    reference_title: "Generation of a mouse model of the neurodevelopmental disorder with dysmorphic facies and distal limb anomalies syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Dysregulated genes were enriched for MYC Proto-Oncogene, BHLH
      Transcription Factor (Myc)-binding sites, a known BPTF transcriptional
      cofactor.
    explanation: >-
      Identifies the MYC cofactor axis as a route by which BPTF loss
      redistributes transcriptional output.

- name: Neural Progenitor Cell-Cycle Prolongation and Apoptosis
  biological_scale: CELLULAR
  mechanism_confidence: ESTABLISHED
  description: >-
    In the developing forebrain, loss of Bptf prolongs neural progenitor cell
    cycle length and raises the incidence of programmed cell death, so fewer
    neurons are produced from the progenitor pool. Independently, CRISPR
    knockout of bptf in zebrafish increases apoptosis (TUNEL) in the developing
    head. Reduced neuronal output from a depleted and slow-cycling progenitor
    pool is the proximate cellular cause of the reduced brain size.
  cell_types:
  - preferred_term: cortical 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: apoptotic process
    term:
      id: GO:0006915
      label: apoptotic process
    modifier: INCREASED
  - preferred_term: cell cycle
    term:
      id: GO:0007049
      label: cell cycle
    modifier: ABNORMAL
  downstream:
  - target: Cortical Hypoplasia and Disrupted Lamination
    causal_link_type: DIRECT
    description: >-
      Reduced neuronal output from a slow-cycling, apoptosis-prone progenitor
      pool yields a hypoplastic cortex.
  evidence:
  - reference: PMID:35604347
    reference_title: "Generation of a mouse model of the neurodevelopmental disorder with dysmorphic facies and distal limb anomalies syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Prolonged progenitor cell cycle length and a high incidence of cell death
      reduced the neuronal output.
    explanation: >-
      Direct statement of the cellular mechanism in the disease-specific
      forebrain-conditional Bptf knockout mouse.
  - reference: PMID:28942966
    reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      showed a significant increase in cell death in F0 mutants compared to
      controls
    explanation: >-
      Independent, cross-species (zebrafish) confirmation that bptf loss
      increases apoptosis during neurodevelopment.

- name: Cortical Hypoplasia and Disrupted Lamination
  biological_scale: TISSUE
  mechanism_confidence: ESTABLISHED
  description: >-
    Reduced neuronal output produces severe cortical hypoplasia with a disrupted
    laminar architecture: the proportion of deep-layer neurons is reduced and
    neuronal maturation defects impair the acquisition of distinct cortical cell
    fates such as Ctip2-positive identity. This is the tissue-level substrate of
    the postnatal microcephaly and the mild structural brain abnormalities seen
    on human MRI.
  cell_types:
  - preferred_term: cortical projection neuron
    term:
      id: CL:0000540
      label: neuron
  biological_processes:
  - preferred_term: cerebral cortex development
    term:
      id: GO:0021987
      label: cerebral cortex development
    modifier: ABNORMAL
  - preferred_term: cerebral cortex neuron differentiation
    term:
      id: GO:0021895
      label: cerebral cortex neuron differentiation
    modifier: DECREASED
  locations:
  - preferred_term: cerebral cortex
    term:
      id: UBERON:0000956
      label: cerebral cortex
  downstream:
  - target: Postnatal Microcephaly and Growth Restriction
    causal_link_type: DIRECT
  - target: Neurodevelopmental Impairment
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      A hypoplastic, mislaminated cortex with impaired neuronal fate acquisition
      underlies the cognitive, language, and motor phenotype.
  - target: Structural Brain Abnormality
    causal_link_type: DIRECT
    description: >-
      The hypoplastic, mislaminated cortex is what the mild non-specific
      structural changes on human brain MRI depict.
  - target: Epilepsy
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      A cortex built with reduced deep-layer neurons and impaired fate
      acquisition is an epileptogenic substrate, consistent with developmental
      delay preceding seizure onset. The circuit-level route from mislamination
      to seizures has not been established in NEDDFL, hence unknown
      intermediates.
  - target: EEG Abnormality
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      The same abnormal cortex produces interictal epileptiform discharges in
      individuals who never have clinical seizures.
  evidence:
  - reference: PMID:35604347
    reference_title: "Generation of a mouse model of the neurodevelopmental disorder with dysmorphic facies and distal limb anomalies syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      The Bptf cKO mice were born in normal Mendelian ratios, survived to
      adulthood but were smaller in size with severe cortical hypoplasia.
    explanation: >-
      Establishes cortical hypoplasia with reduced body size as the tissue-level
      phenotype of forebrain Bptf loss.
  - reference: PMID:35604347
    reference_title: "Generation of a mouse model of the neurodevelopmental disorder with dysmorphic facies and distal limb anomalies syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Cortical lamination was also disrupted with reduced proportions of deep
      layer neurons, and neuronal maturation defects that impaired the
      acquisition of distinct cell fates
    explanation: >-
      Documents the laminar and cell-fate component of the cortical phenotype.

- name: Disrupted Craniofacial and Limb Patterning
  biological_scale: TISSUE
  mechanism_confidence: PROVISIONAL
  description: >-
    Loss of BPTF-dependent spatial control of homeobox gene expression perturbs
    morphogenesis of the craniofacial skeleton and the distal limb. In zebrafish
    bptf F0 mutants the ceratohyal angle of the craniofacial skeleton is
    substantially increased, an established readout of abnormal craniofacial
    patterning. In humans the corresponding findings are the mild dysmorphic
    facial gestalt and the distal limb anomalies (cutaneous toe syndactyly,
    sandal gap, fifth-finger clinodactyly) that name the syndrome. The mechanism
    connecting BPTF dosage to the specific human limb findings has not been
    directly demonstrated and is inferred from the patterning role of NURF, so
    this node is marked PROVISIONAL.
  biological_processes:
  - preferred_term: embryonic skeletal system morphogenesis
    term:
      id: GO:0048704
      label: embryonic skeletal system morphogenesis
    modifier: ABNORMAL
  - preferred_term: embryonic limb morphogenesis
    term:
      id: GO:0030326
      label: embryonic limb morphogenesis
    modifier: ABNORMAL
  cell_types:
  - preferred_term: migratory cranial neural crest cell
    term:
      id: CL:0000008
      label: migratory cranial neural crest cell
  downstream:
  - target: Dysmorphic Facial Features
    causal_link_type: DIRECT
    description: >-
      Disrupted cranial neural crest patterning of the facial skeleton is
      expressed as the mild recognizable facial gestalt.
  - target: Distal Limb Anomalies
    causal_link_type: DIRECT
    description: >-
      The same patterning perturbation in the autopod is expressed as the mild
      hand and foot anomalies that name the syndrome. Inherits this node's
      PROVISIONAL status: the limb arm is inferred from the patterning role of
      NURF and has not been directly demonstrated.
  notes: >-
    No causal edge is drawn from this node to Neurodevelopmental Impairment.
    The dysmorphic and distal limb findings co-segregate with the
    neurodevelopmental phenotype as parallel outputs of one upstream lesion;
    they do not cause it. Both branches are already reachable from
    Dysregulated Developmental Gene Transcription, so the pathograph loses no
    connectivity by omitting an edge that the evidence does not support.
  evidence:
  - reference: PMID:28942966
    reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      we observed a substantial increase of the ceratohyal angle of the
      craniofacial skeleton in bptf F0 mutants, indicating abnormal craniofacial
      patterning
    explanation: >-
      Experimental demonstration that bptf loss disrupts craniofacial
      patterning, the model-organism correlate of the human dysmorphic facies.
  - reference: PMID:16728976
    reference_title: "A PHD finger of NURF couples histone H3 lysine 4 trimethylation with chromatin remodelling."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      NURF-mediated ATP-dependent chromatin remodelling is directly coupled to
      H3K4 trimethylation to maintain Hox gene expression patterns during
      development
    explanation: >-
      Supplies the HOX-patterning link that makes limb and craniofacial
      patterning a plausible consequence of BPTF loss; indirect with respect to
      the human limb findings, hence PARTIAL.
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The mechanism for these abnormalities is less clear, though it is presumed
      that they are also derived from abnormal signaling during embryogenesis
      similar to the distal limb defects commonly described in these patients.
    explanation: >-
      The disease literature itself states the developmental-patterning
      inference is presumptive, which is why this node is PROVISIONAL.

- name: Postnatal Microcephaly and Growth Restriction
  biological_scale: ORGANISM
  mechanism_confidence: ESTABLISHED
  description: >-
    Reduced brain growth manifests as postnatal (secondary) microcephaly rather
    than congenital microcephaly in most individuals: head circumference is
    frequently normal at birth and falls below the third percentile over
    infancy and childhood. Reduced somatic growth accompanies it, with poor
    weight gain, malnutrition, and short stature; a subset has documented
    growth hormone deficiency.
  downstream:
  - target: Neurodevelopmental Impairment
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Reduced brain volume co-occurs with, and is a biomarker of, the underlying
      neurodevelopmental deficit.
  - target: Postnatal Microcephaly
    causal_link_type: DIRECT
    description: >-
      Reduced postnatal brain growth is measured clinically as a head
      circumference falling below the third percentile after birth.
  - target: Short Stature
    causal_link_type: DIRECT
    description: >-
      The somatic arm of the growth restriction presents as height below the
      third percentile, with growth hormone deficiency documented in a subset.
  - target: Poor Weight Gain and Malnutrition
    causal_link_type: DIRECT
    description: >-
      The same growth restriction presents as poor weight gain and moderate to
      severe malnutrition, compounded by the feeding difficulty.
  evidence:
  - reference: PMID:28942966
    reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      who manifest variable degrees of developmental delay/intellectual
      disability (10/10), speech delay (10/10), postnatal microcephaly (7/9),
      and dysmorphic features (9/10)
    explanation: >-
      Establishes the postnatal (rather than congenital) timing of the
      microcephaly in the founding cohort.
  - reference: PMID:28942966
    reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Using CRISPR-Cas9 genome editing of bptf in zebrafish to induce a loss of
      gene function, we observed a significant reduction in head size of F0
      mutants compared to control larvae.
    explanation: >-
      Model-organism recapitulation of reduced head size on bptf loss.
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      At the time of their most recent clinical assessment, 5/20 (25%)
      individuals exhibited short stature for age and 10/19 (53%) individuals
      had decreased weight for age
    explanation: >-
      Quantifies the somatic growth restriction that accompanies the
      microcephaly.

- name: Neurodevelopmental Impairment
  biological_scale: ORGANISM
  mechanism_confidence: ESTABLISHED
  description: >-
    The organism-level clinical output: global developmental delay and
    intellectual disability with disproportionate speech and language delay,
    motor delay, and hypotonia, spanning a wide severity range from severe
    impairment to mild learning difficulty compatible with independent adult
    life. In a minority, cortical excitability is sufficiently disturbed to
    produce early-childhood-onset epilepsy or isolated interictal epileptiform
    discharges; developmental delay precedes seizure onset, indicating that the
    epilepsy is a consequence of the abnormal cortex rather than its cause.
  downstream:
  - target: Global Developmental Delay
    causal_link_type: DIRECT
    description: >-
      The impairment presents first as delayed attainment of milestones across
      all developmental domains.
  - target: Intellectual Disability
    causal_link_type: DIRECT
    description: >-
      The developmental delay matures into persisting cognitive impairment.
  - target: Delayed Speech and Language Development
    causal_link_type: DIRECT
    description: >-
      Speech and language are disproportionately affected relative to other
      domains, making this the most consistent single manifestation.
  - target: Motor Delay
    causal_link_type: DIRECT
    description: >-
      Gross and fine motor milestones are delayed alongside the cognitive and
      language domains.
  - target: Hypotonia
    causal_link_type: DIRECT
    description: >-
      Reduced muscle tone in infancy is part of the same impairment and
      contributes to the motor delay and feeding difficulty.
  notes: >-
    Phenotypes deliberately left unwired. Cyclical Vomiting Syndrome, the
    ophthalmologic group (Ophthalmologic Abnormalities, Exotropia, Myopia), and
    the axial/maturational skeletal findings (Scoliosis, Delayed Bone Age) are
    recorded clinically but have no established mechanistic route from any node
    in this pathograph, so no causal edge is asserted for them. The source
    literature is explicit that the skeletal mechanism "is less clear", and
    nothing connects BPTF dosage to cyclical vomiting or to the ocular findings
    beyond co-occurrence in the same individuals. Wiring them would manufacture
    causal claims the evidence does not carry; the same reasoning applied to the
    craniofacial/limb-to-neurodevelopment edge removed earlier in this entry.

    The remaining unwired phenotypes are unwired because they roll up under a
    parent that is wired, not because they lack a mechanism. Bulbous Nasal Tip,
    Prominent Nasal Bridge and Pointed Chin are sub-features of the wired
    Dysmorphic Facial Features; Sandal Gap and Fifth-Finger Clinodactyly are
    sub-features of the wired Distal Limb Anomalies; and Feeding Difficulties is
    already attributed to hypotonia in the Hypotonia edge description above.
    Between this paragraph and the previous one, every phenotype in this entry
    that carries no incoming causal edge is accounted for.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Common features included DD and/or ID (23/26, 88%), speech delay (22/26,
      85%), head circumference less than the third percentile for age (11/26,
      42%), motor delay (18/26, 69%), hypotonia (10/26, 38%), and dysmorphic
      features (20/26, 77%).
    explanation: >-
      Quantifies the organism-level clinical output across the largest
      single-study cohort.
  - reference: PMID:38936258
    reference_title: "Epilepsy as a Novel Phenotype of BPTF-Related Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      developmental delay preceding seizure onset
    explanation: >-
      Establishes the temporal ordering that makes epilepsy a downstream
      consequence of the abnormal cortex rather than a driver of the
      developmental delay.

phenotypes:
- category: Neurologic
  name: Global Developmental Delay
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay
  description: >-
    Delayed attainment of developmental milestones across domains, evolving into
    intellectual disability. Severity is wide: from severe impairment requiring
    lifelong support to mild deficits compatible with full-time employment and
    independent adult function.
  notes: >-
    Frequency band from PMID:33522091 (DD and/or ID 23/26, 88% ->
    VERY_FREQUENT); the founding cohort reported 10/10, and the pooled 38-case
    table in PMID:36153657 gives 34/38 (89%), all concordant.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Common features included DD and/or ID (23/26, 88%), speech delay (22/26,
      85%), head circumference less than the third percentile for age (11/26,
      42%), motor delay (18/26, 69%), hypotonia (10/26, 38%), and dysmorphic
      features (20/26, 77%).
    explanation: >-
      Supplies both the association and the 88% denominator underpinning the
      VERY_FREQUENT band.
  - reference: PMID:28942966
    reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      who manifest variable degrees of developmental delay/intellectual
      disability (10/10), speech delay (10/10), postnatal microcephaly (7/9),
      and dysmorphic features (9/10)
    explanation: >-
      Founding cohort: developmental delay/intellectual disability in all ten
      individuals.

- category: Neurologic
  name: Intellectual Disability
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Intellectual disability
    term:
      id: HP:0001249
      label: Intellectual disability
  description: >-
    Persisting cognitive impairment, the mature expression of the developmental
    delay. Severe intellectual disability has been reported particularly in
    individuals whose distal limb anomalies are prominent.
  notes: >-
    Reported jointly with developmental delay as "DD and/or ID" (23/26, 88%) in
    PMID:33522091; the composite denominator is the basis for the band. No
    published series enumerates intellectual disability separately from
    developmental delay.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Common features included DD and/or ID (23/26, 88%), speech delay (22/26,
      85%), head circumference less than the third percentile for age (11/26,
      42%), motor delay (18/26, 69%), hypotonia (10/26, 38%), and dysmorphic
      features (20/26, 77%).
    explanation: >-
      Provides the composite DD/ID fraction.
  - reference: PMID:40415676
    reference_title: "Effects of the Missense Variants on Complete Phenotype and Splicing Variant on Severe Growth Retardation in the BPTF Gene."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We suggest that distal limb abnormalities associated with the BPTF gene
      may accompany a more severe diagnosis of intellectual disability.
    explanation: >-
      Proposes an intra-syndromic severity correlation; a four-case series, so
      recorded as PARTIAL rather than SUPPORT.

- category: Neurologic
  name: Delayed Speech and Language Development
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Delayed speech and language development
    term:
      id: HP:0000750
      label: Delayed speech and language development
  description: >-
    Speech and language delay is a cardinal and disproportionately prominent
    feature of NEDDFL, reported in every individual in the founding cohort and
    in the great majority of all reported individuals.
  notes: >-
    Frequency band from PMID:33522091 (speech delay 22/26, 85% ->
    VERY_FREQUENT); the founding cohort reported 10/10 and the pooled 38-case
    table in PMID:36153657 gives 33/38 (87%).
  evidence:
  - reference: PMID:28942966
    reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      who manifest variable degrees of developmental delay/intellectual
      disability (10/10), speech delay (10/10), postnatal microcephaly (7/9),
      and dysmorphic features (9/10)
    explanation: >-
      Speech delay in 10/10 of the founding cohort.
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Common features included DD and/or ID (23/26, 88%), speech delay (22/26,
      85%), head circumference less than the third percentile for age (11/26,
      42%), motor delay (18/26, 69%), hypotonia (10/26, 38%), and dysmorphic
      features (20/26, 77%).
    explanation: >-
      Supplies the 85% denominator for the VERY_FREQUENT band.

- category: Neurologic
  name: Motor Delay
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Motor delay
    term:
      id: HP:0001270
      label: Motor delay
  description: >-
    Delayed acquisition of gross and fine motor milestones.
  notes: >-
    Frequency band from PMID:33522091 (motor delay 18/26, 69% -> FREQUENT); the
    pooled table in PMID:36153657 reports 68%, concordant.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Common features included DD and/or ID (23/26, 88%), speech delay (22/26,
      85%), head circumference less than the third percentile for age (11/26,
      42%), motor delay (18/26, 69%), hypotonia (10/26, 38%), and dysmorphic
      features (20/26, 77%).
    explanation: >-
      Motor delay in 18/26 (69%) of the expansion cohort, mapping to FREQUENT.

- category: Neurologic
  name: Hypotonia
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Hypotonia
    term:
      id: HP:0001252
      label: Hypotonia
  description: >-
    Reduced muscle tone, typically appreciated in infancy and contributing to
    feeding difficulty and motor delay.
  notes: >-
    Frequency band from PMID:33522091 (hypotonia 10/26, 38% -> FREQUENT); the
    pooled table in PMID:36153657 reports 15/38 (39%), concordant.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Common features included DD and/or ID (23/26, 88%), speech delay (22/26,
      85%), head circumference less than the third percentile for age (11/26,
      42%), motor delay (18/26, 69%), hypotonia (10/26, 38%), and dysmorphic
      features (20/26, 77%).
    explanation: >-
      Hypotonia in 10/26 (38%), mapping to FREQUENT.

- category: Neurologic
  name: Postnatal Microcephaly
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Secondary microcephaly
    term:
      id: HP:0005484
      label: Secondary microcephaly
    onset:
      onset_category: INFANTILE
  description: >-
    Head circumference below the third percentile for age, developing after
    birth. Only a minority of individuals have a head circumference below the
    third percentile at birth, so the microcephaly is predominantly secondary
    (postnatal) rather than congenital.
  notes: >-
    Frequency band from PMID:33522091 (head circumference less than the third
    percentile for age 11/26, 42% -> FREQUENT); the pooled table in
    PMID:36153657 reports 18/37 (49%), concordant. The secondary (postnatal)
    classification rests on the same paper's contrast between 12/20 (60%) below
    the third percentile at last assessment and 4/10 (40%) at birth, and on the
    founding cohort explicitly naming the microcephaly postnatal.
  evidence:
  - reference: PMID:28942966
    reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      who manifest variable degrees of developmental delay/intellectual
      disability (10/10), speech delay (10/10), postnatal microcephaly (7/9),
      and dysmorphic features (9/10)
    explanation: >-
      Names the microcephaly as postnatal and reports it in 7/9 assessed
      individuals in the founding cohort.
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      12/20 (60%) individuals demonstrated a head circumference less than the
      third percentile for age
    explanation: >-
      Quantifies microcephaly at last clinical assessment in the expansion
      cohort.

- category: Neurologic
  name: Epilepsy
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Seizure
    term:
      id: HP:0001250
      label: Seizure
    onset:
      onset_category: CHILDHOOD
  description: >-
    Early-childhood-onset epilepsy (median onset 4 years) occurring in a
    minority of individuals with BPTF null variants. The electroclinical
    signature is a well-organized EEG background with brief bursts of
    generalized spikes and slow waves in about half of cases; developmental
    delay precedes seizure onset. Drug resistance is uncommon (27% of those with
    epilepsy) and levetiracetam is the most widely used and frequently effective
    agent. Seizures were not part of the original 2017 description and are a
    phenotypic expansion.
  notes: >-
    Frequency band from PMID:38936258, which reports early-childhood-onset
    epilepsy in 19% of subjects -> OCCASIONAL (5-29%). PMID:33522091
    independently identified 6/26 individuals with clinical seizures and/or
    abnormal EEG, consistent with the same band.
  evidence:
  - reference: PMID:38936258
    reference_title: "Epilepsy as a Novel Phenotype of BPTF-Related Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Early-childhood-onset epilepsy occurs in 19% of subjects, all presenting
      with a well-organized EEG background associated with generalized
      interictal epileptiform abnormalities in half of these cases. Drug
      resistance is rare.
    explanation: >-
      Supplies both the 19% frequency underpinning the OCCASIONAL band and the
      electroclinical characterization.
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Here, however, we identified six individuals with a history of clinical
      seizures and/or abnormal electroencephalograms (manuscript in
      preparation).
    explanation: >-
      Independent cohort confirming seizures as part of the NEDDFL spectrum and
      noting they were previously unreported.

- category: Neurologic
  name: EEG Abnormality
  phenotype_term:
    preferred_term: EEG abnormality
    term:
      id: HP:0002353
      label: EEG abnormality
  description: >-
    Interictal epileptiform discharges may be present without clinical seizures.
    Two of eleven individuals in the dedicated epilepsy series had IEDs only.
  notes: >-
    Frequency omitted: the denominator (11 individuals) is an
    epilepsy-ascertained series, not an unselected NEDDFL cohort, so a
    population band cannot be derived.
  evidence:
  - reference: PMID:38936258
    reference_title: "Epilepsy as a Novel Phenotype of BPTF-Related Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Eight individuals had epilepsy, one had a single unprovoked seizure, and
      two showed IEDs only.
    explanation: >-
      Documents isolated interictal epileptiform discharges as a distinct
      electrographic finding.

- category: Neurologic
  name: Structural Brain Abnormality
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Abnormal brain morphology
    term:
      id: HP:0012443
      label: Abnormal brain morphology
    severity: MILD
  description: >-
    Brain MRI is normal in most individuals in whom it is performed; where
    abnormal, the findings are mild and non-specific structural changes rather
    than a recognizable malformation. A normal MRI therefore does not exclude
    the diagnosis.
  notes: >-
    Frequency band from PMID:33522091 (5/13 imaged individuals, 38% ->
    FREQUENT); the pooled table in PMID:36153657 reports brain anomalies in
    11/22 (50%). Both denominators are restricted to individuals who underwent
    imaging, which was itself indication-driven, so the band is likely inflated
    relative to the whole NEDDFL population.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Magnetic resonance imaging (MRI) studies were obtained for 13/26 patients
      and were found to be normal in 8/13 cases. The remaining five studies
      demonstrated mild structural abnormalities only
    explanation: >-
      Establishes that brain abnormalities, when present, are mild, that most
      imaged individuals are normal, and supplies the 5/13 denominator.

- category: Craniofacial
  name: Dysmorphic Facial Features
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Abnormal facial shape
    term:
      id: HP:0001999
      label: Abnormal facial shape
    severity: MILD
  description: >-
    A mild but recognizable facial gestalt. The most consistently reported
    elements are nasal: prominent nasal tip, bulbous nasal tip, and prominent
    nasal bridge, together with a pointed chin.
  notes: >-
    Frequency band from PMID:33522091, in which mild dysmorphic features were
    present in all 20 individuals with available dysmorphology assessment
    (20/20 -> VERY_FREQUENT); the same paper reports 20/26 (77%) over the whole
    cohort including individuals not assessed, and the founding cohort reported
    9/10.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      mild dysmorphic features were identified in all available subjects (20/20
      individuals)
    explanation: >-
      Supplies the 20/20 denominator for the VERY_FREQUENT band and establishes
      that the dysmorphism is mild.
  - reference: PMID:28942966
    reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      who manifest variable degrees of developmental delay/intellectual
      disability (10/10), speech delay (10/10), postnatal microcephaly (7/9),
      and dysmorphic features (9/10)
    explanation: >-
      Dysmorphic features in 9/10 of the founding cohort.

- category: Craniofacial
  name: Bulbous Nasal Tip
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Bulbous nose
    term:
      id: HP:0000414
      label: Bulbous nose
  description: >-
    A rounded, broadened nasal tip, one of the recurrent nasal features of the
    NEDDFL facial gestalt.
  notes: >-
    Frequency band from PMID:33522091, in which nasal abnormalities as a group
    (prominent nasal tip, bulbous nasal tip, prominent nasal bridge) were
    present in 9/20 (45%) -> FREQUENT. The individual nasal features are not
    separately enumerated, so this band applies to the nasal-abnormality group
    rather than to bulbous nasal tip alone.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Commonly identified features included a number of nasal abnormalities
      (prominent nasal tip, bulbous nasal tip, and prominent nasal bridge) in
      9/20 (45%) individuals
    explanation: >-
      Names bulbous nasal tip among the recurrent nasal features and supplies
      the 45% group denominator.

- category: Craniofacial
  name: Prominent Nasal Bridge
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Prominent nasal bridge
    term:
      id: HP:0000426
      label: Prominent nasal bridge
  description: >-
    A forward-projecting nasal bridge contributing to the facial gestalt.
  notes: >-
    Same 9/20 (45%) nasal-abnormality group denominator from PMID:33522091 as
    the bulbous nasal tip entry; the individual features are not separately
    enumerated.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Commonly identified features included a number of nasal abnormalities
      (prominent nasal tip, bulbous nasal tip, and prominent nasal bridge) in
      9/20 (45%) individuals
    explanation: >-
      Names prominent nasal bridge among the recurrent nasal features.

- category: Craniofacial
  name: Pointed Chin
  phenotype_term:
    preferred_term: Pointed chin
    term:
      id: HP:0000307
      label: Pointed chin
  description: >-
    A narrow, tapering chin, noted across the published clinical photographs as
    a recurrent element of the facial gestalt.
  notes: >-
    Frequency omitted: PMID:33522091 documents pointed chin only in the
    photograph legend, without a numerator/denominator, so no band can be
    derived.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      bulbous nasal tip (a, d, h, k, m, n), and pointed chin (a, c, d, e, f, i,
      k, m, n)
    explanation: >-
      Clinical photograph annotation documenting pointed chin across multiple
      individuals.

- category: Skeletal
  name: Distal Limb Anomalies
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Distal limb anomalies (hands and feet)
    term:
      id: HP:0011297
      label: Abnormal digit morphology
  description: >-
    Mild anomalies of the hands and feet are one of the two features that name
    the syndrome. The recurrent findings are cutaneous 2-3 toe syndactyly,
    sandal gap, and fifth-finger clinodactyly; a subset also has limb-length
    discrepancy.
  notes: >-
    Frequency band from PMID:33522091, which reports skeletal abnormalities in
    50% (13/26) of the cohort -> FREQUENT. That denominator covers all skeletal
    findings (scoliosis and delayed bone age as well as distal limb anomalies);
    the pooled table in PMID:36153657 gives a higher 23/28 (82%) for skeletal
    abnormalities, but on a partial denominator, so the more conservative
    whole-cohort 50% is used. The individual distal-limb findings are curated as
    separate phenotypes below without bands, because they are reported only as
    raw counts within the skeletal-abnormality subgroup.

    Term-binding note: this is a deliberately group-level record, so it binds
    the parent term HP:0011297 Abnormal digit morphology rather than the
    specific HP:0010621 Cutaneous syndactyly of toes. Binding a specific child
    while carrying a frequency derived from an all-skeletal-findings denominator
    would over-claim that 50% of individuals have toe syndactyly specifically.
    The specific findings are curated separately below (Sandal Gap,
    Fifth-Finger Clinodactyly) and alongside (Scoliosis, Delayed Bone Age), so
    no specificity is lost.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we also identified the presence of skeletal abnormalities in 50% (13/26)
      of individuals
    explanation: >-
      Supplies the whole-cohort skeletal-abnormality fraction underpinning the
      FREQUENT band.
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In addition to DDs, microcephaly, and distal limb defects, our cohort
      exhibited an increased frequency of ophthalmologic abnormalities, poor
      weight gain/poor feeding, and cutaneous syndactyly of the toes.
    explanation: >-
      Names cutaneous syndactyly of the toes as a recurrent distal limb finding.
  - reference: PMID:40415676
    reference_title: "Effects of the Missense Variants on Complete Phenotype and Splicing Variant on Severe Growth Retardation in the BPTF Gene."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Additionally, all four of our cases in this study had distal limb
      abnormalities such as syndactyly and clinodactyly that accompany severe
      intellectual disability.
    explanation: >-
      Independent series confirming syndactyly and clinodactyly as the
      characteristic distal limb anomalies.

- category: Skeletal
  name: Sandal Gap
  phenotype_term:
    preferred_term: Sandal gap
    term:
      id: HP:0001852
      label: Sandal gap
  description: >-
    An increased gap between the first and second toes, reported in five
    individuals in the phenotypic expansion cohort.
  notes: >-
    Frequency omitted: PMID:33522091 reports a raw count of five individuals
    within the subgroup of 13 with skeletal abnormalities, without a whole-cohort
    denominator.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Note the presence of fifth finger clinodactyly (d), sandal gap deformity
      (i, k) and cutaneous syndactyly (j, k)
    explanation: >-
      Clinical photograph annotation documenting sandal gap in the cohort.

- category: Skeletal
  name: Fifth-Finger Clinodactyly
  phenotype_term:
    preferred_term: Clinodactyly of the 5th finger
    term:
      id: HP:0004209
      label: Clinodactyly of the 5th finger
  description: >-
    Radial curvature of the fifth finger, part of the mild hand anomaly
    component of the syndrome.
  notes: >-
    Frequency omitted: documented in PMID:33522091 only as a photograph
    annotation without a denominator, and in PMID:40415676 in all four cases of
    a small ascertained series.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Note the presence of fifth finger clinodactyly (d), sandal gap deformity
      (i, k) and cutaneous syndactyly (j, k)
    explanation: >-
      Clinical photograph annotation documenting fifth-finger clinodactyly.

- category: Skeletal
  name: Scoliosis
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Scoliosis
    term:
      id: HP:0002650
      label: Scoliosis
  description: >-
    Lateral curvature of the spine, reported in five of the 13 individuals with
    skeletal abnormalities in the phenotypic expansion cohort. Careful
    examination and monitoring for scoliosis is recommended in NEDDFL.
  notes: >-
    Band derived conservatively: PMID:33522091 reports 5/13 (38.5%) of the
    skeletal-abnormality subgroup, which corresponds to 5/26 (19%) of the whole
    cohort. The whole-cohort denominator is the appropriate one for a
    disease-level frequency, giving OCCASIONAL (5-29%).
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      These included the presence of scoliosis in five individuals (5/13,
      38.5%)
    explanation: >-
      Supplies the scoliosis count within the skeletal-abnormality subgroup of
      the 26-individual cohort.

- category: Skeletal
  name: Delayed Bone Age
  phenotype_term:
    preferred_term: Delayed skeletal maturation
    term:
      id: HP:0002750
      label: Delayed skeletal maturation
  description: >-
    Bone age delayed relative to chronological age, reported in two individuals
    in the phenotypic expansion cohort.
  notes: >-
    Frequency omitted: only two individuals, reported as a raw count within the
    skeletal-abnormality subgroup of PMID:33522091.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      and delayed bone age in two individuals (2/13, 15%)
    explanation: >-
      Documents delayed skeletal maturation in the cohort.

- category: Growth
  name: Short Stature
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Short stature
    term:
      id: HP:0004322
      label: Short stature
  description: >-
    Height below the third percentile for age. A subset of individuals has
    documented growth hormone deficiency on stimulation testing and responds to
    recombinant human growth hormone.
  notes: >-
    Frequency band from PMID:36153657, which states in its abstract that about
    35% of patients have short stature -> FREQUENT. PMID:33522091 independently
    reports 5/20 (25%) at last assessment, which would map to OCCASIONAL; the
    larger pooled denominator behind the 35% figure is preferred, and the
    discrepancy is recorded here rather than hidden.
  evidence:
  - reference: PMID:36153657
    reference_title: "The effect of growth hormone treatment in children with novel BPTF gene variants: A report of two cases and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      About 35% of the patients had short stature, but there had no reports
      published on the treatment.
    explanation: >-
      Explicit 35% short-stature frequency supporting the FREQUENT band.
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      At the time of their most recent clinical assessment, 5/20 (25%)
      individuals exhibited short stature for age and 10/19 (53%) individuals
      had decreased weight for age
    explanation: >-
      Independent cohort estimate of 25%, lower than the pooled 35%; recorded as
      PARTIAL because it supports the association but a different band.

- category: Growth
  name: Poor Weight Gain and Malnutrition
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Failure to thrive
    term:
      id: HP:0001508
      label: Failure to thrive
  description: >-
    Poor weight gain with moderate to severe malnutrition is common, frequently
    beginning in infancy alongside feeding difficulty.
  notes: >-
    Frequency band from PMID:33522091 (decreased weight for age 10/19, 53% ->
    FREQUENT); the pooled table in PMID:36153657 reports moderate/severe
    malnutrition in 18/33 (55%), concordant.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      At the time of their most recent clinical assessment, 5/20 (25%)
      individuals exhibited short stature for age and 10/19 (53%) individuals
      had decreased weight for age
    explanation: >-
      Quantifies decreased weight for age at 10/19 (53%), mapping to FREQUENT.

- category: Gastrointestinal
  name: Feeding Difficulties
  phenotype_term:
    preferred_term: Feeding difficulties
    term:
      id: HP:0011968
      label: Feeding difficulties
  description: >-
    Poor feeding, contributing to the poor weight gain, and identified as an
    expanded feature of the syndrome.
  notes: >-
    Frequency omitted: PMID:33522091 reports poor feeding qualitatively as an
    increased-frequency finding without a numerator/denominator.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In addition to DDs, microcephaly, and distal limb defects, our cohort
      exhibited an increased frequency of ophthalmologic abnormalities, poor
      weight gain/poor feeding, and cutaneous syndactyly of the toes.
    explanation: >-
      Names poor feeding as an expanded feature of NEDDFL.

- category: Gastrointestinal
  name: Cyclical Vomiting Syndrome
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Episodic vomiting
    term:
      id: HP:0002572
      label: Episodic vomiting
    temporality: RECURRENT
  description: >-
    Stereotyped, recurrent episodes of vomiting, typically lasting under an
    hour, with a median onset around age 3 years and common triggers of poor
    sleep and fever. Formally diagnosed as cyclical vomiting syndrome by ICHD-3
    criteria in 20% of one prospectively questioned series, with a further 27%
    meeting at least three of the criteria. Episodes are a substantial source of
    family burden.
  notes: >-
    Frequency band from PMID:40614698: 3/15 (20%) met full ICHD-3 CVS criteria
    -> OCCASIONAL (5-29%). The band uses the strict diagnostic denominator; if
    partial criteria are included the fraction rises to 7/15 (47%), which would
    be FREQUENT. The conservative strict-criteria band is recorded here. Note
    also that the series was recruited with a focus on gastrointestinal
    symptoms, so ascertainment may inflate the fraction.
  evidence:
  - reference: PMID:40614698
    reference_title: "Cyclical Vomiting Syndrome in Individuals With BPTF Haploinsufficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We enrolled 15 individuals with likely pathogenic/pathogenic BPTF variants
      (median age: 8.8 years). Three individuals (20%) were diagnosed with CVS,
      and an additional four individuals (26.7%) met at least three of the
      ICHD-3 criteria for CVS.
    explanation: >-
      Supplies the 20% strict-criteria frequency underpinning the OCCASIONAL
      band.
  - reference: PMID:40614698
    reference_title: "Cyclical Vomiting Syndrome in Individuals With BPTF Haploinsufficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This study broadens the syndromic phenotype associated with BPTF
      haploinsufficiency, highlighting CVS as a core feature.
    explanation: >-
      Establishes cyclical vomiting as part of the BPTF haploinsufficiency
      phenotype rather than an incidental comorbidity.

- category: Ophthalmologic
  name: Ophthalmologic Abnormalities
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Mild ophthalmologic abnormalities
    term:
      id: HP:0000478
      label: Abnormality of the eye
    severity: MILD
  description: >-
    Mild ophthalmologic abnormalities are common and were a key finding of the
    phenotypic expansion. Exotropia is the most frequent specific finding,
    followed by other strabismus and myopia.
  notes: >-
    Frequency band from PMID:33522091, which identified mild ophthalmologic
    abnormalities in 13 of the 26-individual cohort (50% -> FREQUENT); the
    pooled table in PMID:36153657 reports 17/30 (57%), concordant.

    Term-binding note: the 50% denominator counts all ophthalmologic
    abnormalities, not strabismus specifically (the same 13 individuals split
    into exotropia in six, other strabismus in two, and myopia in three), so
    this group-level record binds the parent HP:0000478 Abnormality of the eye
    rather than HP:0000486 Strabismus. Binding Strabismus here would assert a
    50% strabismus frequency the source does not support. Exotropia and Myopia
    are curated as separate specific phenotypes below.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Interestingly, 13 individuals demonstrated mild ophthalmologic
      abnormalities. These included the finding of exotropia in six individuals,
      strabismus in two individuals, and confirmed myopia in three individuals.
    explanation: >-
      Supplies the 13/26 denominator and breaks the ophthalmologic group down
      into exotropia, strabismus, and myopia.

- category: Ophthalmologic
  name: Exotropia
  phenotype_term:
    preferred_term: Exotropia
    term:
      id: HP:0000577
      label: Exotropia
  description: >-
    Divergent strabismus, the most frequently reported single ophthalmologic
    finding in NEDDFL (six individuals in the phenotypic expansion cohort).
  notes: >-
    Frequency omitted: reported as a raw count of six individuals in
    PMID:33522091, but the number of individuals who actually underwent
    ophthalmologic assessment is not stated, so the denominator is ambiguous.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Interestingly, 13 individuals demonstrated mild ophthalmologic
      abnormalities. These included the finding of exotropia in six individuals,
      strabismus in two individuals, and confirmed myopia in three individuals.
    explanation: >-
      Documents exotropia as the most common specific ophthalmologic finding.

- category: Ophthalmologic
  name: Myopia
  phenotype_term:
    preferred_term: Myopia
    term:
      id: HP:0000545
      label: Myopia
  description: >-
    Confirmed myopia in three individuals in the phenotypic expansion cohort.
  notes: >-
    Frequency omitted for the same denominator ambiguity as exotropia.
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Interestingly, 13 individuals demonstrated mild ophthalmologic
      abnormalities. These included the finding of exotropia in six individuals,
      strabismus in two individuals, and confirmed myopia in three individuals.
    explanation: >-
      Documents confirmed myopia in the cohort.

treatments:
- name: Supportive and Developmental Therapy
  description: >-
    There is no disease-modifying therapy for NEDDFL. Management is supportive
    and centres on early intervention: speech and language therapy (given the
    disproportionate speech delay), physical and occupational therapy for motor
    delay and hypotonia, educational support, nutritional support for poor
    weight gain and feeding difficulty, and periodic monitoring for scoliosis
    and ophthalmologic problems.
  action_category: THERAPEUTIC
  therapeutic_modality: BEHAVIORAL
  treatment_term:
    preferred_term: supportive care
    term:
      id: NCIT:C15747
      label: Supportive Care
  target_phenotypes:
  - preferred_term: Delayed speech and language development
    term:
      id: HP:0000750
      label: Delayed speech and language development
  - preferred_term: Motor delay
    term:
      id: HP:0001270
      label: Motor delay
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      While it is unclear how significant the degree of scoliosis was within
      individuals, careful examination and monitoring for this clinical finding
      are also recommended.
    explanation: >-
      Supports the surveillance component of supportive management. No trial
      evidence exists for developmental therapy in NEDDFL specifically, so this
      is recorded as PARTIAL.

- name: Recombinant Human Growth Hormone
  description: >-
    Recombinant human growth hormone (somatropin, rhGH) has been used in NEDDFL
    children with short stature and documented growth hormone deficiency on
    arginine and levodopa stimulation testing. In the first reported use, one
    child gained 25.6 cm (+1.63 SD) over 3.5 years of treatment. Evidence is
    limited to two uncontrolled case reports and rhGH should not be regarded as
    an established standard of care in NEDDFL.
  action_category: THERAPEUTIC
  therapeutic_modality: PROTEIN_REPLACEMENT
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: recombinant human growth hormone (somatropin)
      term:
        id: NCIT:C837
        label: Somatropin
  target_phenotypes:
  - preferred_term: Short stature
    term:
      id: HP:0004322
      label: Short stature
  evidence:
  - reference: PMID:36153657
    reference_title: "The effect of growth hormone treatment in children with novel BPTF gene variants: A report of two cases and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Both children had short stature and responded to recombinant human growth
      hormone (rhGH) treatment - the first report of this therapy in NEDDFL
      patients.
    explanation: >-
      First and, to date, principal report of growth hormone therapy in NEDDFL.
  - reference: PMID:36153657
    reference_title: "The effect of growth hormone treatment in children with novel BPTF gene variants: A report of two cases and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The salutary effect of rhGH in the NEDDFL is documented.
    explanation: >-
      Authors' summary conclusion; PARTIAL because the evidence base is two
      uncontrolled cases with no comparator.

- name: Antiseizure Medication
  description: >-
    Levetiracetam is the most widely used antiseizure medication in
    BPTF-related epilepsy and reduced seizure frequency in two-thirds of treated
    individuals. Drug-resistant epilepsy is uncommon (27% of those with
    epilepsy); other agents used in the reported series include sodium valproate
    and lamotrigine, and one individual required vagal nerve stimulator
    placement.
  action_category: THERAPEUTIC
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: levetiracetam
      term:
        id: CHEBI:6437
        label: levetiracetam
  target_phenotypes:
  - preferred_term: Seizure
    term:
      id: HP:0001250
      label: Seizure
  evidence:
  - reference: PMID:38936258
    reference_title: "Epilepsy as a Novel Phenotype of BPTF-Related Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Levetiracetam was widely used and reduced seizure frequency in 67% of the
      cases.
    explanation: >-
      Direct evidence of levetiracetam effectiveness in BPTF-related epilepsy.

- name: Cyclical Vomiting Syndrome Therapy
  description: >-
    Acute treatment of cyclical vomiting episodes with ondansetron or
    domperidone, and prophylaxis with cyproheptadine, domperidone, or
    levetiracetam combined with lamotrigine, were all associated with clinical
    benefit in the reported BPTF series. Evidence is observational and from a
    single 15-individual questionnaire study.
  action_category: THERAPEUTIC
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: ondansetron
      term:
        id: CHEBI:7773
        label: Ondansetron
    - preferred_term: cyproheptadine
      term:
        id: CHEBI:4046
        label: cyproheptadine
  target_phenotypes:
  - preferred_term: Episodic vomiting
    term:
      id: HP:0002572
      label: Episodic vomiting
  evidence:
  - reference: PMID:40614698
    reference_title: "Cyclical Vomiting Syndrome in Individuals With BPTF Haploinsufficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Acute therapy (ondansetron or domperidone) was administered in 42.8% of
      cases, and prophylactic therapy was provided in 57.1% of cases with
      cyproheptadine, levetiracetam combined with lamotrigine, and domperidone;
      all therapies were associated with clinical benefit.
    explanation: >-
      Observational report of benefit from acute and prophylactic CVS therapy;
      uncontrolled, hence PARTIAL.

- name: Genetic Counseling
  description: >-
    Genetic counseling should address the autosomal dominant inheritance, the
    50% recurrence risk for an affected parent, the possibility that an
    apparently de novo variant is inherited from a mildly affected parent (four
    such families are documented), the residual recurrence risk from parental
    germline mosaicism after an apparently de novo variant, and the variable
    expressivity of the disorder.
  action_category: COUNSELING_INFORMATIONAL
  therapeutic_modality: BEHAVIORAL
  treatment_term:
    preferred_term: genetic counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Our study has also uncovered four cases of inherited BPTF variants,
      providing some insight into the penetrance and expressivity of NEDDFL.
    explanation: >-
      Documented inherited variants are the basis for counseling about parental
      testing and recurrence risk.

animal_models:
- name: Bptf forebrain-conditional knockout mouse
  species: Mus musculus
  genotype: Emx1-Cre forebrain-conditional Bptf knockout (Bptf cKO)
  category: Conditional knockout mouse model of NEDDFL
  description: >-
    Forebrain-specific Bptf knockout mice, generated explicitly to model NEDDFL
    (PMID:35604347). They are born at normal Mendelian ratios and survive to
    adulthood but are smaller, with severe cortical hypoplasia, prolonged
    progenitor cell cycle length, increased cell death, disrupted cortical
    lamination with reduced deep-layer neurons, and impaired acquisition of
    distinct neuronal fates.
  notes: >-
    Interpretive caveat beyond the per-link limitations: ablation of Smarca1
    (the SNF2L ATPase partner of BPTF within NURF) produces mice with ENLARGED
    brains, the direct contrast of the NEDDFL microcephaly, so the two NURF
    subunits cannot be treated as interchangeable when modelling this disorder.
    That discordance is the basis of the `bptf_vs_smarca1_dosage_paradox`
    knowledge gap.
  modeled_mechanisms:
  - target: Neural Progenitor Cell-Cycle Prolongation and Apoptosis
    relationship: RECAPITULATES
    description: >-
      The model directly demonstrates the cellular mechanism this node asserts:
      prolonged progenitor cell cycle length and increased programmed cell death
      reducing neuronal output from the progenitor pool.
    readouts:
    - name: Progenitor cell cycle length
      target: Neural Progenitor Cell-Cycle Prolongation and Apoptosis
      direction: INCREASED
      description: >-
        Cell cycle length of cortical neural progenitors in Bptf cKO versus
        littermate control forebrain.
      interpretation: >-
        Lengthened cycle time is the measured basis for the reduced neuronal
        output asserted by this node.
    - name: Progenitor cell death incidence
      target: Neural Progenitor Cell-Cycle Prolongation and Apoptosis
      direction: INCREASED
      biological_processes:
      - preferred_term: apoptotic process
        term:
          id: GO:0006915
          label: apoptotic process
      description: >-
        Incidence of programmed cell death among cortical progenitors in Bptf
        cKO versus control.
      interpretation: >-
        Raised cell death compounds the cycle-length effect in depleting the
        progenitor pool.
    evidence:
    - reference: PMID:35604347
      reference_title: "Generation of a mouse model of the neurodevelopmental disorder with dysmorphic facies and distal limb anomalies syndrome."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Prolonged progenitor cell cycle length and a high incidence of cell death
        reduced the neuronal output.
      explanation: >-
        States the progenitor cell-cycle and apoptosis phenotype that this node
        asserts.
  - target: Cortical Hypoplasia and Disrupted Lamination
    relationship: RECAPITULATES
    fidelity: MODERATE
    description: >-
      Reproduces both facets of the node: severe cortical hypoplasia, and
      disrupted lamination with reduced deep-layer neurons and impaired
      acquisition of distinct cortical cell fates.
    readouts:
    - name: Deep-layer neuron proportion
      target: Cortical Hypoplasia and Disrupted Lamination
      direction: DECREASED
      description: >-
        Proportion of deep-layer neurons within the cortical plate of Bptf cKO
        versus control.
      interpretation: >-
        A reduced deep-layer fraction is the quantitative signature of the
        disrupted lamination this node asserts.
    - name: Ctip2-positive neuronal fate acquisition
      target: Cortical Hypoplasia and Disrupted Lamination
      direction: DECREASED
      biological_processes:
      - preferred_term: cerebral cortex neuron differentiation
        term:
          id: GO:0021895
          label: cerebral cortex neuron differentiation
      description: >-
        Acquisition of distinct cortical identities, indexed by Ctip2-positive
        neurons, in Bptf cKO versus control.
      interpretation: >-
        Impaired fate acquisition distinguishes a maturation defect from simple
        cell loss.
    limitations: >-
      The model is a homozygous conditional null restricted to the forebrain,
      not a heterozygous haploinsufficiency model, and heterozygous animals were
      reported to have little to no phenotype. Its severe cortical hypoplasia is
      therefore a complete-loss phenotype whose quantitative relationship to the
      human half-dosage disease is unresolved. This is the substance of the
      `bptf_mouse_homozygous_vs_human_haploinsufficiency` HUMAN_MODEL_MISMATCH
      discussion, which attaches to this same node.
    evidence:
    - reference: PMID:35604347
      reference_title: "Generation of a mouse model of the neurodevelopmental disorder with dysmorphic facies and distal limb anomalies syndrome."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Cortical lamination was also disrupted with reduced proportions of deep
        layer neurons, and neuronal maturation defects that impaired the
        acquisition of distinct cell fates
      explanation: >-
        Documents the laminar and cell-fate facets of the node that the model
        reproduces.
  evidence:
  - reference: PMID:35604347
    reference_title: "Generation of a mouse model of the neurodevelopmental disorder with dysmorphic facies and distal limb anomalies syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      To model the NEDDFL syndrome, we generated forebrain-specific Bptf
      knockout (Bptf conditional Knockout (cKO)) mice.
    explanation: >-
      Establishes the model's purpose and construction.
  - reference: PMID:35604347
    reference_title: "Generation of a mouse model of the neurodevelopmental disorder with dysmorphic facies and distal limb anomalies syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Surprisingly, ablation of Smarca1 resulted in mice with enlarged brains, a
      direct contrast to the phenotype of NEDDFL patients.
    explanation: >-
      Records the SMARCA1 discordance that limits inference from NURF ATPase
      knockouts to BPTF haploinsufficiency.

- name: bptf CRISPR F0 crispant zebrafish
  species: Danio rerio
  genotype: CRISPR-Cas9 bptf F0 crispant
  category: CRISPR F0 knockout zebrafish model
  description: >-
    CRISPR-Cas9 knockout of zebrafish bptf produces F0 mutant larvae with
    significantly reduced head size, increased apoptosis by TUNEL staining, and
    a substantially increased ceratohyal angle indicating abnormal craniofacial
    patterning (PMID:28942966). This model recapitulates both the microcephaly
    and the craniofacial dimensions of NEDDFL.
  modeled_mechanisms:
  - target: Postnatal Microcephaly and Growth Restriction
    relationship: PARTIALLY_RECAPITULATES
    fidelity: MODERATE
    description: >-
      Reduced head size in bptf F0 larvae is the cross-species correlate of the
      human microcephaly.
    readouts:
    - name: Larval head size
      target: Postnatal Microcephaly and Growth Restriction
      direction: DECREASED
      description: >-
        Head size of bptf F0 crispant larvae versus control larvae.
      interpretation: >-
        Significantly reduced head size is the model's microcephaly readout; it
        indexes reduced brain growth but not the postnatal timing of the human
        phenotype.
    limitations: >-
      Only partially recapitulates the human node. The zebrafish readout is
      larval head size in a complete loss-of-function crispant, so it captures
      reduced brain growth but not the defining postnatal (secondary) timing of
      the human microcephaly, and it says nothing about the accompanying somatic
      growth restriction, short stature, or growth hormone deficiency.
    evidence:
    - reference: PMID:28942966
      reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Using CRISPR-Cas9 genome editing of bptf in zebrafish to induce a loss of
        gene function, we observed a significant reduction in head size of F0
        mutants compared to control larvae.
      explanation: >-
        Reduced head size is the model's microcephaly readout; PARTIAL because
        larval head size does not capture the postnatal timing or the somatic
        growth arm of the human node.
  - target: Disrupted Craniofacial and Limb Patterning
    relationship: RECAPITULATES
    description: >-
      Increased ceratohyal angle is an established quantitative readout of
      disrupted craniofacial patterning, and is the direct experimental support
      for the craniofacial arm of this node.
    readouts:
    - name: Ceratohyal angle
      target: Disrupted Craniofacial and Limb Patterning
      direction: INCREASED
      description: >-
        Angle of the ceratohyal cartilage of the craniofacial skeleton in bptf
        F0 crispants versus controls.
      interpretation: >-
        A substantially widened ceratohyal angle is the established quantitative
        index of abnormal craniofacial patterning in zebrafish.
    limitations: >-
      Supports the craniofacial arm only. No model has yet demonstrated the
      distal limb arm of this node, which is why the node is marked PROVISIONAL.
    evidence:
    - reference: PMID:28942966
      reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        we observed a substantial increase of the ceratohyal angle of the
        craniofacial skeleton in bptf F0 mutants, indicating abnormal craniofacial
        patterning
      explanation: >-
        Direct experimental demonstration of disrupted craniofacial patterning on
        bptf loss.
  evidence:
  - reference: PMID:28942966
    reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Using CRISPR-Cas9 genome editing of bptf in zebrafish to induce a loss of
      gene function, we observed a significant reduction in head size of F0
      mutants compared to control larvae.
    explanation: >-
      Establishes the zebrafish model and its microcephaly readout.

- name: Constitutive Bptf-null mouse embryo
  species: Mus musculus
  genotype: Constitutive Bptf-null (gene-trap) embryo
  category: Constitutive null mouse embryo
  description: >-
    Constitutive Bptf mouse mutants manifest growth defects at the
    post-implantation stage and are resorbed by E8.5, failing to establish a
    functional distal visceral endoderm (PMID:18974875). This establishes Bptf
    as essential for early mammalian development and is the basis for the
    anterior-posterior axis role cited in the human disease literature.
  modeled_mechanisms:
  - target: BPTF Haploinsufficiency
    relationship: PERTURBS
    fidelity: LOW
    description: >-
      Establishes that Bptf dosage is developmentally critical in a mammal,
      which is the premise that makes a 50% reduction a credible human disease
      mechanism.
    readouts:
    - name: Post-implantation embryonic survival
      target: BPTF Haploinsufficiency
      direction: DECREASED
      description: >-
        Survival of constitutive Bptf-null embryos, which show post-implantation
        growth defects and are resorbed by E8.5.
      interpretation: >-
        Complete loss is embryonic-lethal, establishing Bptf as dosage-critical;
        it does not measure the heterozygous state this node describes.
    limitations: >-
      Low fidelity to the human node. This is a constitutive homozygous null
      causing embryonic lethality by E8.5, two dosage steps away from the human
      heterozygous, viable, postnatally manifesting disorder. It demonstrates
      gene essentiality, not the consequences of haploinsufficiency, and no
      heterozygous phenotype is reported.
    evidence:
    - reference: PMID:18974875
      reference_title: "Essential role of chromatin remodeling protein Bptf in early mouse embryos and embryonic stem cells."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Bptf mutants manifest growth defects at the post-implantation stage and
        are reabsorbed by E8.5.
      explanation: >-
        Demonstrates embryonic essentiality of Bptf; PARTIAL with respect to the
        haploinsufficiency node because the genotype is a homozygous null.
  evidence:
  - reference: PMID:18974875
    reference_title: "Essential role of chromatin remodeling protein Bptf in early mouse embryos and embryonic stem cells."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Bptf mutants manifest growth defects at the post-implantation stage and
      are reabsorbed by E8.5.
    explanation: >-
      Establishes the embryonic essentiality of Bptf that makes heterozygous
      dosage reduction plausible as a human disease mechanism.
diagnosis:
- name: Trio Exome or Genome Sequencing
  description: >-
    First-line testing for unexplained syndromic developmental delay or
    intellectual disability. Trio exome sequencing (or genome sequencing, which
    combines sequence and structural-variant detection) with copy-number calling
    is the highest-yield route to a NEDDFL diagnosis, and is how most reported
    individuals were ascertained. Trio design matters here because the majority
    of pathogenic BPTF variants are de novo, and parental testing is what
    distinguishes a de novo variant from the transmitted alleles documented in
    four families.
  diagnosis_term:
    preferred_term: whole exome sequencing
    term:
      id: NCIT:C101295
      label: Whole Exome Sequencing
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Molecular testing results from exome sequencing, chromosomal microarray,
      or next‐generation sequencing panel were submitted by patients'
      healthcare providers
    explanation: >-
      Documents the diagnostic modalities through which the 26-individual
      expansion cohort was actually ascertained.
  - reference: PMID:40415676
    reference_title: "Effects of the Missense Variants on Complete Phenotype and Splicing Variant on Severe Growth Retardation in the BPTF Gene."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      BPTF gene variants were detected using whole-exome sequencing. Family
      segregation analysis was performed using sanger sequencing.
    explanation: >-
      Independent series confirming exome sequencing as the detection method,
      with Sanger segregation analysis in the family.
  - reference: PMID:36153657
    reference_title: "The effect of growth hormone treatment in children with novel BPTF gene variants: A report of two cases and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The exome sequencing was performed in two probands. Sanger sequencing was
      used to confirm the identified variants both in probands and their parents.
    explanation: >-
      Shows the standard workflow of exome discovery plus Sanger confirmation in
      proband and parents.

- name: Chromosomal Microarray for 17q24.2 Copy-Number Variants
  description: >-
    Chromosomal microarray remains informative because a meaningful share of the
    reported allelic spectrum is copy-number: single-exon and whole-gene BPTF
    deletions, larger 17q24.2 deletions, and a chromosomal translocation
    disrupting the gene. Microarray was part of the ascertainment of the
    founding and expansion cohorts. A larger 17q24.2 deletion should be
    interpreted as a potential contiguous-gene event rather than attributed to
    BPTF alone.
  diagnosis_term:
    preferred_term: chromosomal microarray (array comparative genomic hybridization)
    term:
      id: NCIT:C18084
      label: Comparative Genomic Hybridization
  evidence:
  - reference: PMID:28942966
    reference_title: "Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we report eight loss-of-function and two missense variants (eight de novo
      and two of unknown origin) in BPTF on 17q24.2
    explanation: >-
      Establishes the 17q24.2 locus that copy-number testing must cover.
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Molecular testing results from exome sequencing, chromosomal microarray,
      or next‐generation sequencing panel were submitted by patients'
      healthcare providers
    explanation: >-
      Confirms chromosomal microarray as one of the modalities that identified
      individuals in the expansion cohort.

- name: ACMG/AMP Variant Interpretation with Parental Testing
  description: >-
    Diagnosis requires a compatible phenotype plus a BPTF variant classified
    under ACMG/AMP criteria, supported by parental testing, phenotype match,
    population frequency, and predicted loss of function. In the expansion
    cohort, 20 variants were classified as 11 pathogenic, 7 likely pathogenic,
    and 2 VUS. Truncating and copy-number alleles are straightforward because
    loss of function is the established mechanism; missense alleles are the hard
    case and a missense VUS alone does not establish the diagnosis. That caution
    is not merely theoretical: severely affected missense carriers have since
    been reported (PMID:40415676), so a missense VUS can be neither dismissed
    nor accepted on phenotype severity alone.
  diagnosis_term:
    preferred_term: genetic testing
    term:
      id: NCIT:C15709
      label: Genetic Testing
  evidence:
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Variants were interpreted as pathogenic (11), likely pathogenic (7), or VUS
      (2) based on the current ACMG criteria.
    explanation: >-
      Documents ACMG/AMP classification as the interpretation framework and the
      residual VUS rate.
  - reference: PMID:33522091
    reference_title: "Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      it is anticipated that the finding of missense variants in BPTF may present
      a diagnostic challenge for practitioners, particularly in individuals with
      mild phenotypes
    explanation: >-
      The authors flag missense variants as the principal interpretation
      difficulty, supporting the caution that a missense VUS alone is not
      diagnostic.
  notes: >-
    Explicit negatives, recorded so their absence is not mistaken for a curation
    gap. (1) There are no formal consensus diagnostic criteria for NEDDFL;
    diagnosis is a compatible phenotype plus molecular confirmation. (2) There is
    no diagnostic biochemical, enzymatic, imaging, or circulating biomarker - a
    normal brain MRI in particular does not exclude the diagnosis, since most
    imaged individuals in the expansion cohort had normal studies. (3) No
    validated functional assay and no DNA-methylation episignature has been
    established for BPTF, despite NEDDFL being a chromatinopathy where an
    episignature might be expected; RNA sequencing and proteomics for resolving
    difficult variants remain investigational. (4) No newborn or general
    population screening exists; cascade testing is appropriate once a familial
    pathogenic variant is known.

differential_diagnoses:
- name: Neurodevelopmental disorder with dysmorphic facies and distal skeletal anomalies (ZMIZ1)
  disease_term:
    preferred_term: NEDDFSA
    term:
      id: MONDO:0032855
      label: neurodevelopmental disorder with dysmorphic facies and distal skeletal anomalies
  description: >-
    A separate autosomal dominant neurodevelopmental entity caused by
    heterozygous ZMIZ1 variants. Its MONDO label differs from this disorder's by
    a single word ("skeletal" versus "limb"), which makes it the single highest
    named-entity-confusion risk for NEDDFL in any label- or text-based search.
  distinguishing_features:
  - >-
    Molecular: ZMIZ1 versus BPTF (hgnc:3581). The gene is the only reliable
    discriminator; confirm the causative gene before importing any cohort data
    published under either "dysmorphic facies and distal ... anomalies" phrasing.
  - >-
    Nomenclature: the near-identical labels are the hazard, not the phenotypes.
    Both are dominant neurodevelopmental syndromes with dysmorphism and distal
    appendicular findings.
  notes: >-
    No literature evidence item is attached here deliberately: the point of this
    record is the identity distinction, which is established by the MONDO/OMIM
    identifiers themselves rather than by a phenotype claim. Adding a ZMIZ1
    cohort citation to a BPTF entry would reintroduce exactly the confusion this
    record exists to prevent.

- name: OTUD6B-related intellectual developmental disorder with dysmorphic facies, seizures and distal limb anomalies
  disease_term:
    preferred_term: IDDFSDA
    term:
      id: MONDO:0044319
      label: intellectual developmental disorder with dysmorphic facies, seizures, and distal limb anomalies
  description: >-
    An ultra-rare autosomal recessive multisystem disorder caused by biallelic
    OTUD6B variants (OMIM:617452), a ubiquitin-proteasome-system disorder of
    development. It shares the "dysmorphic facies ... and distal limb anomalies"
    phrasing with NEDDFL and overlaps clinically (developmental delay,
    microcephaly, dysmorphism, distal limb findings), but is mechanistically and
    genetically distinct.
  distinguishing_features:
  - >-
    Inheritance: biallelic and autosomal recessive (OTUD6B) versus heterozygous
    and autosomal dominant, typically de novo (BPTF). The inheritance mode alone
    separates them in almost every family.
  - >-
    Mechanism: impaired 26S proteasome assembly and reduced chymotrypsin-like
    proteasome activity (OTUD6B) versus impaired NURF ATP-dependent chromatin
    remodeling (BPTF).
  - >-
    Seizures are a defining, near-universal feature of the OTUD6B disorder and
    are named in its label, whereas in NEDDFL epilepsy occurs in a minority
    (about 19%) and was absent from the original clinical description.
  notes: >-
    The dismech OTUD6B entry carries the reciprocal NEC guardrail and
    deliberately excludes PMID:33522091 from all of its claims because that
    paper describes NEDDFL. The exclusion is honoured in the opposite direction
    here: no OTUD6B-specific citation is used anywhere in this BPTF entry.
  evidence:
  - reference: PMID:38936258
    reference_title: "Epilepsy as a Novel Phenotype of BPTF-Related Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Epilepsy was not included in the initial descriptions of NEDDFL, but
      emerging evidence indicates that epileptic seizures occur in some affected
      individuals.
    explanation: >-
      Supports the distinguishing feature that seizures are a late-recognized,
      minority finding in NEDDFL, unlike the OTUD6B disorder in which seizures
      are part of the disease name and the defining phenotype.

- name: Silver-Russell syndrome
  description: >-
    A clinical phenocopy hazard rather than a nomenclature hazard: the
    combination of small-for-gestational-age birth, poor postnatal growth,
    a small triangular face, and feeding difficulty can prompt an initial
    diagnosis of Silver-Russell syndrome in a child later found to have BPTF
    disruption. At least one adult carried the Silver-Russell label for 35 years
    before BPTF disruption was identified.
  distinguishing_features:
  - >-
    NEDDFL has postnatal (secondary) microcephaly, whereas relative macrocephaly
    for body size is characteristic of Silver-Russell syndrome.
  - >-
    NEDDFL has prominent speech delay and intellectual disability; cognition is
    typically preserved or only mildly affected in Silver-Russell syndrome.
  - >-
    Silver-Russell syndrome is most often caused by 11p15 loss of methylation or
    maternal uniparental disomy of chromosome 7, neither of which involves BPTF.
  notes: >-
    Recorded on the basis of the published case title (PMID:30633344,
    "Neurodevelopmental disorder with dysmorphic facies and distal limb
    anomalies syndrome due to disruption of BPTF in a 35-year-old man initially
    diagnosed with Silver-Russell syndrome"). No evidence item is attached
    because no abstract text is available for that reference in the reference
    cache, and dismech policy forbids quoting text that cannot be verified
    against a cached source.

discussions:
- discussion_id: bptf_vs_smarca1_dosage_paradox
  kind: KNOWLEDGE_GAP
  status: OPEN
  prompt: >-
    Why does BPTF haploinsufficiency cause microcephaly when loss of its NURF
    ATPase partner SMARCA1/SNF2L causes brain overgrowth?
  attaches_to:
  - pathophysiology#Impaired NURF Chromatin-Remodeling Activity
  rationale: >-
    The simplest model of NEDDFL is that reduced BPTF impairs NURF, and impaired
    NURF impairs cortical neurogenesis. That model predicts that removing the
    NURF catalytic ATPase should phenocopy BPTF loss. It does not: Smarca1-null
    mice have enlarged brains, the direct opposite of the NEDDFL phenotype. This
    means either that BPTF has NURF-independent functions in the developing
    cortex, or that the two subunits have opposing dosage effects on the same
    complex, or that SNF2H-containing complexes compensate for Smarca1 loss but
    not for Bptf loss. Which of these is true determines whether NURF is
    actually the right therapeutic target concept for NEDDFL.
  proposed_experiments:
  - experiment_id: bptf_smarca1_side_by_side_cortex
    name: Side-by-side cortical comparison of Bptf and Smarca1 conditional knockouts
    description: >-
      Compare cortical transcriptomes and progenitor kinetics side by side in
      forebrain-conditional Bptf and Smarca1 knockouts on the same genetic
      background, to determine whether the dysregulated gene sets overlap or
      diverge.
  - experiment_id: bptf_snf2l_cooccupancy_map
    name: BPTF and SNF2L chromatin co-occupancy mapping in cortical progenitors
    description: >-
      Map BPTF chromatin occupancy in cortical progenitors and ask what fraction
      of BPTF-bound sites are also SNF2L-bound, to quantify the size of the
      NURF-independent BPTF binding compartment.
  - experiment_id: bptf_myc_axis_microcephaly_test
    name: Test whether the BPTF-MYC axis accounts for the Bptf-specific microcephaly
    description: >-
      Test whether the NURF-independent BPTF interactome, including the MYC
      cofactor axis identified by RNA-seq binding-site enrichment, accounts for
      the microcephaly that Smarca1 loss fails to reproduce.
  evidence:
  - reference: PMID:35604347
    reference_title: "Generation of a mouse model of the neurodevelopmental disorder with dysmorphic facies and distal limb anomalies syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Surprisingly, ablation of Smarca1 resulted in mice with enlarged brains, a
      direct contrast to the phenotype of NEDDFL patients.
    explanation: >-
      This is the observation that creates the gap: the NURF ATPase knockout
      gives the opposite brain-size phenotype to BPTF loss.

- discussion_id: bptf_mouse_homozygous_vs_human_haploinsufficiency
  kind: HUMAN_MODEL_MISMATCH
  status: OPEN
  prompt: >-
    Does the homozygous forebrain-conditional Bptf knockout mouse faithfully
    model human BPTF haploinsufficiency, given that heterozygous animals show
    little to no phenotype?
  attaches_to:
  - pathophysiology#Cortical Hypoplasia and Disrupted Lamination
  rationale: >-
    Human NEDDFL is a heterozygous, dosage-sensitivity disorder: one null allele
    produces microcephaly, intellectual disability, and speech delay. The
    principal mouse model is a homozygous conditional null restricted to the
    forebrain, and heterozygous mice were reported to have little to no
    phenotype. The mouse's severe cortical hypoplasia is therefore a
    complete-loss phenotype, not a half-dosage phenotype, and the cellular
    mechanism it reveals (prolonged progenitor cell cycle, increased apoptosis,
    lamination failure) may be quantitatively or qualitatively different from
    what a 50% reduction produces in a human cortex. The species difference in
    dosage sensitivity is itself the open question. This is a translational
    validity problem, not an absence of evidence, hence HUMAN_MODEL_MISMATCH
    rather than KNOWLEDGE_GAP.
  proposed_experiments:
  - experiment_id: bptf_het_mouse_deep_phenotyping
    name: Deep cortical phenotyping of Bptf heterozygous mice
    description: >-
      Phenotype Bptf heterozygous mice quantitatively for cortical volume,
      laminar composition, and progenitor kinetics rather than by gross
      inspection, to establish whether a subtle half-dosage phenotype exists.
  - experiment_id: bptf_het_ipsc_cortical_organoid
    name: Isogenic heterozygous BPTF-null human cortical organoids
    description: >-
      Derive isogenic human iPSC lines carrying patient BPTF null alleles in the
      heterozygous state and assay cortical organoid size, progenitor cell cycle
      length, and deep-layer neuron output against isogenic controls.
  - experiment_id: bptf_dosage_response_cross_species
    name: Cross-species BPTF dosage-response comparison
    description: >-
      Compare BPTF dosage-response curves for NURF assembly and target-gene
      expression between mouse and human cortical progenitors, to test whether
      the human system is simply steeper.
  evidence:
  - reference: PMID:35604347
    reference_title: "Generation of a mouse model of the neurodevelopmental disorder with dysmorphic facies and distal limb anomalies syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      To model the NEDDFL syndrome, we generated forebrain-specific Bptf
      knockout (Bptf conditional Knockout (cKO)) mice.
    explanation: >-
      Identifies the model whose homozygous conditional-null design is the
      source of the mismatch with the human heterozygous disorder.

📚

References & Deep Research

References

3

PMID:28942966

Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features.

No top-level findings curated for this source.

PMID:33522091

Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies.

No top-level findings curated for this source.

PMID:36153657

The effect of growth hormone treatment in children with novel BPTF gene variants: A report of two cases and literature review.

No top-level findings curated for this source.

Deep Research

1

Falcon ▸

BPTF-Related Neurodevelopmental Disorder: Comprehensive Disease-Characteristics Report

Edison Scientific Literature 21 citations 2026-08-15T08:40:47.422885

BPTF-Related Neurodevelopmental Disorder: Comprehensive Disease-Characteristics Report

Executive summary and evidence limits

BPTF-related neurodevelopmental disorder is a rare Mendelian chromatin-remodeling disorder, conventionally named neurodevelopmental disorder with dysmorphic facies and distal limb anomalies (NEDDFL). It results primarily from heterozygous loss-of-function variants in BPTF and is best understood as an autosomal-dominant haploinsufficiency disorder. Developmental/intellectual disability, speech-language delay, postnatal microcephaly, and recognizable but variable dysmorphism form the core phenotype; motor delay, hypotonia, growth impairment, seizures, mild brain abnormalities, ophthalmologic findings, scoliosis, and distal-limb anomalies broaden the spectrum. The evidence base remains small: the landmark 2017 study described ten unrelated individuals, and the major 2021 expansion reported approximately 25–26 affected individuals with 20 distinct variants. Consequently, frequencies below are cohort proportions—not population estimates—and are vulnerable to referral and ascertainment bias. (glinton2021phenotypicexpansionof pages 1-3, stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 3-4)

Recent disease-specific literature is sparse. Important 2023 and 2024 reports concern growth-hormone use and epilepsy, respectively, but their full text was unavailable in the retrieved corpus; they are therefore flagged without extrapolating outcomes. No disease-specific interventional trial was identified. The strongest mechanistic development is the 2022 forebrain-specific mouse model and its RNA-sequencing analysis. (zapata2022generationofa pages 1-2)

1. Disease information

Definition and nomenclature

Preferred name: BPTF-related neurodevelopmental disorder.
Established alternative name: neurodevelopmental disorder with dysmorphic facies and distal limb anomalies.
Abbreviation: NEDDFL.
Category: Mendelian, syndromic neurodevelopmental disorder/chromatinopathy.

The 2021 abstract defines NEDDFL as being “defined primarily by developmental delay/intellectual disability, speech delay, postnatal microcephaly, and dysmorphic features” and resulting from heterozygous variants in dosage-sensitive BPTF. (glinton2021phenotypicexpansionof pages 1-3)

Identifiers

OMIM phenotype: 617755, NEDDFL.
Gene/locus: BPTF, chromosome 17q24.2.
MONDO: a disease-specific MONDO accession could not be verified from the retrieved primary literature; do not assign one without direct MONDO lookup.
Orphanet: no disease-specific Orpha code was verified.
ICD-10/ICD-11 and MeSH: no specific code/descriptor was identified. Coding generally requires broader categories for developmental/intellectual disability, microcephaly, epilepsy, or congenital malformations.

The source data are aggregated disease-level data from published case series and experimental studies, not an EHR-derived natural-history cohort. Individual-patient observations underlie the aggregate proportions. (stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 3-4)

2. Etiology

Causal factor

The primary cause is a heterozygous germline pathogenic variant or deletion affecting BPTF. The leading mechanism is reduced dosage—haploinsufficiency—rather than infection, toxin exposure, autoimmunity, or a metabolic enzyme defect. The 2017 cohort contained eight loss-of-function and two missense variants; the expanded cohort was dominated by frameshift, nonsense, splice, and exon-level loss variants. (glinton2021phenotypicexpansionof pages 3-4, stankiewicz2017haploinsufficiencyofthe pages 1-2)

Genetic risk

A pathogenic BPTF allele is itself the principal risk factor. Most initially reported variants were de novo, but the 2021 study documented four inherited changes, including transmission from non-mosaic affected parents, demonstrating vertical autosomal-dominant transmission and variable expressivity. (glinton2021phenotypicexpansionof pages 3-4)

No validated modifier gene, susceptibility locus, protective allele, founder mutation, ancestry enrichment, or carrier-frequency estimate is established. Missense and some inherited variants have been associated with milder presentations, but this is not yet a validated genotype–phenotype rule. (glinton2021phenotypicexpansionof pages 12-13, glinton2021phenotypicexpansionof pages 3-4)

Environmental and protective factors

No causal environmental, occupational, lifestyle, dietary, or infectious exposure has been demonstrated. No genetic or environmental protective factor has been reported. There is likewise no disease-specific gene–environment interaction literature. These are evidence gaps, not evidence that environmental influences can never affect clinical functioning.

3. Phenotypes

The most reproducible phenotype data are summarized below. Differences between quoted frequencies reflect different denominators, missing data, and whether the calculation concerned the novel cohort or all available individuals.

Neurodevelopmental and neurologic features

Developmental delay/intellectual disability: 10/10 in the 2017 cohort and approximately 88% in the 2021 expanded cohort. Severity is variable; onset is infancy/childhood and impairment is generally chronic. Suggested terms: HP:0001263 Global developmental delay, HP:0001249 Intellectual disability. (stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 3-4)
Speech-language delay: 10/10 in 2017 and approximately 85% in 2021. This is among the most consistent, functionally important manifestations. Suggested term: HP:0000750 Delayed speech and language development. (stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 3-4)
Motor delay: approximately 69% in the expanded cohort. Suggested term: HP:0001270 Motor delay. (glinton2021phenotypicexpansionof pages 3-4)
Hypotonia: history in approximately 38%. Suggested term: HP:0001252 Hypotonia. (glinton2021phenotypicexpansionof pages 4-5)
Microcephaly: postnatal microcephaly occurred in 7/9 in 2017. The expanded-study extractions report 42% in one denominator and 60% at assessment in another, while 40% had microcephaly at birth. The safest conclusion is that microcephaly is common but neither universal nor always strictly postnatal. Suggested terms: HP:0000252 Microcephaly and, only where serial measurements document it, HP:0000253 Progressive microcephaly. (stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 4-5)
Seizures/EEG abnormalities: six expanded-cohort participants had a seizure history requiring treatment; two additional individuals had electrographic abnormalities without reported clinical seizures. Suggested terms: HP:0001250 Seizure, HP:0010843 Abnormality of the EEG. (glinton2021phenotypicexpansionof pages 4-5)
Brain MRI: among 13 imaged individuals, 8 MRIs were normal and 5 showed mild structural abnormalities. Thus, a normal MRI does not exclude the disorder. Suggested term: HP:0410263 Abnormal brain MRI when applicable. (glinton2021phenotypicexpansionof pages 4-5)

Growth, craniofacial, skeletal, and ocular features

Short stature: approximately 25%; decreased weight/poor weight gain: approximately 53%. Suggested terms: HP:0004322 Short stature, HP:0004325 Decreased body weight/Poor weight gain, with exact HPO chosen to match the measured phenotype. (glinton2021phenotypicexpansionof pages 4-5)
Dysmorphism: 9/10 in 2017; 77% in one 2021 aggregate, while all 20 individuals with detailed available dysmorphology data had mild dysmorphism. Recurrent descriptions include a prominent nasal ridge, bulbous nasal tip, and pointed chin. Suggested umbrella term: HP:0001999 Facial dysmorphism, supplemented by feature-specific terms. (stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 4-5, glinton2021phenotypicexpansionof pages 9-10)
Distal-limb/skeletal abnormalities: cutaneous syndactyly, sandal gap, limb-length discrepancy, delayed bone age, and scoliosis occur variably. Suggested terms include HP:0001159 Syndactyly and HP:0002650 Scoliosis. (glinton2021phenotypicexpansionof pages 9-10, glinton2021phenotypicexpansionof pages 1-3)
Ophthalmologic complications: reported as an expanded component of the phenotype, but precise frequencies and diagnoses were unavailable in the extracted evidence. Use HP:0000478 Abnormality of the eye only as a parent term pending patient-specific coding. (glinton2021phenotypicexpansionof pages 1-3)

Behavioral, laboratory, and quality-of-life data

No consistent disease-specific psychiatric or behavioral profile, biochemical laboratory signature, validated patient-reported outcome, EQ-5D/SF-36 dataset, or formal quality-of-life study was identified. Nevertheless, cognitive, speech, motor, seizure, and visual impairments predict substantial effects on communication, education, independence, and caregiver burden. That functional interpretation is clinically reasonable but has not been quantified specifically for NEDDFL.

4. Genetic and molecular information

Gene and variant spectrum

BPTF encodes bromodomain PHD finger transcription factor, the largest subunit of the nucleosome-remodeling factor (NURF) complex. In 2017, ten unrelated individuals carried eight loss-of-function and two missense variants; eight variants were confirmed de novo and two had unresolved parental origin. (stankiewicz2017haploinsufficiencyofthe pages 1-2)

The expanded study reported 20 distinct variants: 9 frameshift, 4 nonsense, 3 splice, 2 in-frame deletion, 1 missense, and 1 single-exon deletion. Reported ACMG classifications were 11 pathogenic, 7 likely pathogenic, and 2 VUS. Four causative changes were inherited and fourteen were de novo in the available summary. Appropriate Sequence Ontology classes include frameshift_variant, stop_gained, splice_donor_variant, splice_acceptor_variant, inframe_deletion, missense_variant, and exon_loss_variant. (glinton2021phenotypicexpansionof pages 3-4)

Variants are germline in the constitutional disorder. Somatic BPTF alterations studied in cancer should not be conflated with NEDDFL. Population frequencies were not available in the retrieved evidence; pathogenic loss-of-function variants are expected to be very rare, but every candidate requires direct gnomAD/ClinVar evaluation using its exact HGVS expression.

Functional consequence and epigenetics

The best-supported consequence is loss of function and haploinsufficiency. BPTF recognizes H3K4me3 through its PHD finger and H4K16ac through its bromodomain, helping recruit/position the NURF ATP-dependent remodeling machinery at chromatin. The disorder is therefore an epigenetic chromatin-remodeling disease, although no validated diagnostic DNA-methylation episignature was identified. (glinton2021phenotypicexpansionof pages 1-3)

No dominant-negative or gain-of-function disease mechanism, modifier gene, or reproducible human methylomic signature has been established. Large deletions involving 17q24.2 may produce broader contiguous-gene phenotypes and require CNV interpretation rather than automatic attribution solely to BPTF.

5. Environmental information

No toxin, radiation, pollution, occupational exposure, smoking, diet, alcohol, exercise pattern, or infectious agent is known to cause or trigger this Mendelian disorder. Lifestyle measures remain relevant to general health and management of secondary complications but are not primary prevention for a pathogenic germline BPTF variant. There is no zoonotic or transmissible component.

6. Mechanism and pathophysiology

Causal chain

The most defensible causal model is:

Upstream genetic lesion: heterozygous BPTF loss-of-function/deletion lowers functional BPTF dosage.
Chromatin-level defect: impaired NURF targeting/remodeling alters nucleosome positioning and transcriptional accessibility at developmentally regulated loci.
Neural-progenitor consequences: altered fate-determining transcription factors, prolonged progenitor cell cycle, and increased apoptosis reduce neuronal output.
Corticogenesis defect: impaired neuronal maturation and specification, reduced deep-layer neurons, and disrupted cortical lamination produce cortical hypoplasia.
Clinical manifestations: impaired cortical growth and circuit development plausibly generate microcephaly, developmental/intellectual disability, speech delay, motor impairment, and seizure susceptibility. (glinton2021phenotypicexpansionof pages 1-3, zapata2022generationofa pages 1-2)

In the 2022 mouse study, forebrain-specific Bptf loss produced “severe cortical hypoplasia”; prolonged progenitor cycling and high cell death reduced neuronal output, while lamination and acquisition of neuronal identities such as CTIP2-positive fates were impaired. RNA-seq showed dysregulation of fate-determining transcription factors and pathways involving neural development, apoptotic signaling, and amino-acid biosynthesis; dysregulated genes were enriched for MYC-binding sites, consistent with BPTF–MYC transcriptional cooperation. (zapata2022generationofa pages 1-2)

Suggested functional ontology

GO:0006338 chromatin remodeling
GO:0042393 histone binding
GO:0006357 regulation of transcription by RNA polymerase II
GO:0022008 neurogenesis
GO:0007399 nervous system development
GO:0006915 apoptotic process
GO:0051301 cell division
GO:0008652 cellular amino-acid biosynthetic process
GO:0005634 nucleus
GO:0000785 chromatin

Suggested cell annotations are neural progenitor cell, radial glial/neural stem cell, cortical projection neuron, deep-layer cortical neuron, and generic neuron (CL:0000540); subtype accessions should be checked against the current Cell Ontology release.

Molecular profiling and advanced technologies

Disease-relevant molecular profiling currently consists principally of mouse forebrain bulk RNA-seq. No robust human patient-brain transcriptome, proteome, metabolome, lipidome, single-cell atlas, spatial-transcriptomic dataset, organoid study, or clinical multi-omics signature was identified. The 2021 clinical authors noted the absence of a well-validated functional assay and suggested RNA-seq or proteomics might help resolve difficult variants, particularly missense variants; this remains investigational rather than standard diagnosis. (glinton2021phenotypicexpansionof pages 12-13)

There is no evidence that immune dysregulation, chronic inflammation, ischemia, fibrosis, mitochondrial failure, or a discrete metabolic block is a primary mechanism. Altered amino-acid-biosynthesis pathways in knockout mouse RNA-seq are downstream expression findings, not proof of a treatable human metabolic deficiency. (zapata2022generationofa pages 1-2)

7. Anatomical structures affected

The principal organ system is the central nervous system, especially the developing forebrain/cerebral cortex. Suggested anatomy terms include UBERON:0000955 brain, UBERON:0001890 cerebral cortex, and a current UBERON term for telencephalon/forebrain. Human imaging can be normal or show mild abnormalities, whereas complete forebrain-specific knockout in mice produces marked cortical hypoplasia. (zapata2022generationofa pages 1-2, glinton2021phenotypicexpansionof pages 4-5)

Secondary systems include craniofacial structures, distal limbs/skeleton, eyes, and general somatic growth. The relevant tissue is nervous tissue; implicated cells are neural progenitors and differentiating/mature cortical neurons. The main subcellular compartment is nuclear chromatin. Findings are not described as unilateral or lateralized.

8. Temporal development

The disorder is developmental, with congenital or early-childhood onset. Growth restriction or microcephaly may be present at birth, whereas some individuals develop postnatal microcephaly. Delayed milestones and language become evident in infancy or early childhood. (stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 4-5)

The course is chronic and lifelong rather than episodic or relapsing-remitting. Published ages extended from 23 months to 55 years in the expanded cohort, demonstrating adult survival. There is no validated staging system, progression rate, remission pattern, or defined end stage. Early childhood is likely the most important intervention window for speech, motor, educational, visual, and seizure services, but no study has quantified a critical therapeutic period. (glinton2021phenotypicexpansionof pages 3-4)

9. Inheritance and population

Inheritance is autosomal dominant. Most pathogenic variants arise de novo, although affected-parent transmission is established. When a parent carries the variant, the theoretical transmission probability is 50% per pregnancy; actual phenotype severity cannot be predicted reliably because expressivity is variable. For an apparently de novo variant, recurrence risk is low but not zero because parental germline mosaicism cannot be excluded by routine blood testing. (glinton2021phenotypicexpansionof pages 3-4)

Penetrance has not been quantified. Anticipation, founder effects, consanguinity effects, population-specific variants, and carrier frequency are not established. Both sexes are affected; one summary reported 14 males and 11 females, with no evidence for sex-linked inheritance. The published sample spans childhood through middle adulthood. (glinton2021phenotypicexpansionof pages 3-4)

No prevalence, incidence, geographic clustering, ancestry excess, or registry-derived epidemiologic estimate is available. It should be represented as an ultra-rare disorder of unknown prevalence rather than assigning a numerical rate.

10. Diagnostics

Recommended genomic approach

There are no formal NEDDFL diagnostic criteria. Diagnosis requires a compatible phenotype plus molecular confirmation.

First-line broad testing: trio exome sequencing or genome sequencing for unexplained syndromic developmental delay/intellectual disability, ideally with copy-number calling.
CNV testing: chromosomal microarray remains useful for exon/gene or larger 17q24.2 deletions and was used in foundational ascertainment. Genome sequencing may combine sequence and structural-variant detection.
Panel testing: a neurodevelopmental disorder/intellectual-disability or chromatinopathy panel should include BPTF and provide validated deletion/duplication analysis.
Single-gene testing: most appropriate when the phenotype is strongly suggestive or for familial segregation, prenatal diagnosis, and cascade testing.
Variant interpretation: apply ACMG/AMP criteria, parental testing, phenotype match, population frequency, predicted loss of function, transcript relevance, and CNV boundaries. A BPTF missense VUS alone does not establish diagnosis. (glinton2021phenotypicexpansionof pages 12-13, stankiewicz2017haploinsufficiencyofthe pages 1-2)

Karyotyping and FISH have low sensitivity for small sequence variants and are reserved for suspected large rearrangements or confirmation. Mitochondrial DNA and repeat-expansion testing are not disease-specific tests. RNA sequencing may help establish splice effects; proteomics and epigenomics remain investigational. (glinton2021phenotypicexpansionof pages 12-13)

Clinical evaluation after diagnosis

Recommended baseline assessment, extrapolated from the observed spectrum, includes detailed developmental/neuropsychological and speech-language evaluation; serial height, weight, and head circumference; neurologic examination; EEG for suspected seizures; brain MRI when neurologically indicated; ophthalmology; hearing assessment; musculoskeletal examination for scoliosis and limb anomalies; and review of feeding/nutrition. These are pragmatic surveillance recommendations, not evidence-based NEDDFL guidelines.

There is no blood, urine, enzyme, biopsy, metabolite, protein, or circulating biomarker diagnostic for the syndrome.

Differential diagnosis

Consider other chromatin-remodeling/chromatin-reader disorders, syndromic intellectual disability with microcephaly, copy-number syndromes involving 17q24, and growth disorders. Phenotypic overlap can include Silver–Russell syndrome: a cited adult with BPTF disruption was initially given that diagnosis. Distinction depends on genomic testing rather than facial gestalt alone. (glinton2021phenotypicexpansionof pages 13-13)

No newborn population screening or general-population carrier screening is available. Cascade testing is appropriate once a familial pathogenic variant is established.

11. Outcome and prognosis

No survival curve, disease-specific mortality rate, or life-expectancy estimate exists. Survival into adulthood—including an individual aged 55 years—has been documented, but the literature is too small to conclude that life expectancy is normal. (glinton2021phenotypicexpansionof pages 3-4)

Long-term morbidity is primarily neurodevelopmental and functional: communication limitations, intellectual disability, motor delay/hypotonia, epilepsy in a subset, growth impairment, ocular complications, and orthopedic issues. Recovery to a premorbid state is not expected because the condition reflects altered development; nevertheless, function can improve with therapy, education, communication supports, and control of secondary complications. No validated prognostic biomarker or genotype-based outcome calculator exists.

12. Treatment and real-world implementation

There is no approved disease-modifying, gene, RNA, cell, epigenetic, or targeted therapy for BPTF-related neurodevelopmental disorder. Management is individualized and multidisciplinary:

early developmental intervention and special education;
speech-language therapy, including augmentative and alternative communication where needed;
physical and occupational therapy for hypotonia, motor delay, mobility, and adaptive skills;
standard antiseizure treatment guided by seizure type and EEG;
ophthalmologic correction/treatment;
nutritional and feeding support;
orthopedic surveillance and treatment for scoliosis or limb-related functional problems;
psychosocial and family support.

Suggested NCIT concepts include Genetic Counseling, Supportive Care, Speech Therapy, Physical Therapy, Occupational Therapy, Anticonvulsant Therapy, and Vagus Nerve Stimulation; current NCIT identifiers should be validated during ingestion.

Case-level antiseizure implementations in the 2021 cohort included sodium valproate, levetiracetam, and a vagal nerve stimulator. These observations show real-world use but do not establish comparative efficacy or syndrome-specific response rates. (glinton2021phenotypicexpansionof pages 4-5)

A 2023 publication, Wu and Chen, “The effect of growth hormone treatment in children with novel BPTF gene variants: a report of two cases and literature review,” Molecular Genetics & Genomic Medicine, DOI 10.1002/mgg3.2066, was identified. Because direct outcome data were unavailable in the retrieved evidence, growth hormone should not be portrayed as established NEDDFL therapy; its use would require conventional endocrinologic evaluation and individualized risk–benefit review.

A 2024 epilepsy-focused report, Ferretti et al., “Epilepsy as a novel phenotype of BPTF-related disorders,” Pediatric Neurology, DOI 10.1016/j.pediatrneurol.2024.06.001, indicates growing characterization of seizure phenotypes, but detailed statistics could not be verified here.

No BPTF/NEDDFL-specific interventional ClinicalTrials.gov study or treatment algorithm was identified. Pharmacogenomic guidance specific to BPTF is absent.

13. Prevention

There is no lifestyle, medication, vaccine, or environmental intervention that prevents a de novo pathogenic BPTF variant. Primary prevention is therefore limited to informed reproductive options when a familial variant is known: genetic counseling, prenatal diagnosis, and preimplantation genetic testing for monogenic disease. Secondary prevention consists of early molecular diagnosis and prompt developmental, communication, vision, nutritional, orthopedic, and epilepsy evaluation. Tertiary prevention aims to reduce complications and maximize function through ongoing multidisciplinary care.

For confirmed de novo cases, parental testing informs recurrence counseling but cannot eliminate residual germline-mosaicism risk. For inherited variants, cascade testing can identify relatives who may benefit from clinical evaluation and reproductive counseling. (glinton2021phenotypicexpansionof pages 3-4)

14. Other species and natural disease

No naturally occurring BPTF-associated veterinary disease, affected breed, zoonotic potential, or cross-species transmission was identified. Orthologous developmental function is conserved experimentally in vertebrates. Relevant taxa are Danio rerio (NCBI Taxonomy 7955) and Mus musculus (NCBI Taxonomy 10090). Species-specific Bptf gene identifiers should be obtained directly from the current NCBI Gene/Alliance records before database ingestion.

15. Model organisms

Zebrafish

CRISPR-Cas9 disruption of bptf in F0 zebrafish caused reduced head size, increased TUNEL-positive apoptosis, altered phospho-histone-H3 proliferation measures, and abnormal craniofacial patterning, including increased ceratohyal angle. This recapitulates the human microcephaly/craniofacial axis and supports a developmental loss-of-function mechanism. Limitations include F0 mosaicism, uncertain allele dosage, and incomplete modeling of cognition and speech. (stankiewicz2017haploinsufficiencyofthe pages 1-2)

Mouse

The 2022 Emx1-Cre forebrain-specific Bptf conditional knockout survived into adulthood but was smaller and had severe cortical hypoplasia, prolonged progenitor cycling, increased cell death, reduced neuronal output, disturbed lamination, fewer deep-layer neurons, and impaired neuronal maturation. It is a strong mechanistic model for corticogenesis and transcriptomic studies. Its major limitation is that biallelic tissue-specific ablation is more severe and spatially restricted than constitutional human heterozygous haploinsufficiency; heterozygous mice reportedly had much smaller effects. (glinton2021phenotypicexpansionof pages 1-3, zapata2022generationofa pages 1-2)

No validated patient-derived iPSC, brain-organoid, rat, Drosophila, C. elegans, or naturally occurring animal model was identified in the retrieved disease-specific evidence.

Recent research and authoritative interpretation

The field’s current interpretation is that BPTF-related NDD belongs to the broader class of dosage-sensitive chromatinopathies. Human genetics strongly supports haploinsufficiency, while zebrafish and mouse experiments connect the genetic lesion to apoptosis, progenitor dysfunction, reduced neuronal production, and impaired cortical fate specification. The major unresolved translational challenge is that the severe knockout models do not precisely reproduce the variable heterozygous human phenotype. Human cellular models and variant-sensitive functional assays are priorities, particularly for missense and inherited variants. (zapata2022generationofa pages 1-2, glinton2021phenotypicexpansionof pages 12-13)

The most important recent developments are therefore phenotypic rather than therapeutic: recognition of inherited disease and milder expression, expanded seizure and ophthalmologic phenotypes, exploratory growth-hormone treatment, and mechanistic forebrain RNA-seq. No precision therapy has reached clinical implementation.

Key primary sources and abstract quotations

Stankiewicz et al. “Haploinsufficiency of the Chromatin Remodeler BPTF Causes Syndromic Developmental and Speech Delay, Postnatal Microcephaly, and Dysmorphic Features.” American Journal of Human Genetics 101:503–515. Published October 2017. DOI: 10.1016/j.ajhg.2017.08.014. Landmark human cohort plus zebrafish validation: ten unrelated individuals, 8 loss-of-function and 2 missense variants, with DD/ID and speech delay in 10/10. (stankiewicz2017haploinsufficiencyofthe pages 1-2)
Glinton et al. “Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies.” American Journal of Medical Genetics Part A 185:1366–1378. Published January 2021. DOI: 10.1002/ajmg.a.62102. Abstract quotation: “To expand the NEDDFL phenotypic spectrum, we describe the clinical features in 25 novel individuals with 20 distinct, clinically relevant variants in BPTF, including four individuals with inherited changes in BPTF.” It further reports “mild brain abnormalities, seizures, scoliosis, and a variety of ophthalmologic complications.” (glinton2021phenotypicexpansionof pages 1-3)
Zapata, Yan, and Picketts. “Generation of a mouse model of the neurodevelopmental disorder with dysmorphic facies and distal limb anomalies (NEDDFL) syndrome.” Human Molecular Genetics 31:3405–3421. Published May 2022. DOI: 10.1093/hmg/ddac119. Abstract quotation: “Prolonged progenitor cell cycle length and a high incidence of cell death reduced neuronal output.” The authors also report disrupted cortical lamination, neuronal maturation defects, and RNA-seq pathway changes. (zapata2022generationofa pages 1-2)

Knowledge-base-ready summary

The following artifact consolidates evidence-supported disease, phenotype, mechanism, diagnostic, treatment, anatomy, and model annotations, while explicitly marking unverified identifiers and unknown fields.

domain	evidence-based finding	suggested ontology terms	evidence strength/limitations
Disease name/definition	BPTF-related neurodevelopmental disorder is also called neurodevelopmental disorder with dysmorphic facies and distal limb anomalies (NEDDFL); core syndrome includes developmental delay/intellectual disability, speech delay, postnatal microcephaly, and dysmorphic features due to heterozygous BPTF variants (glinton2021phenotypicexpansionof pages 1-3, stankiewicz2017haploinsufficiencyofthe pages 1-2)	OMIM:617755; MONDO: not verified/uncertain; disease label: NEDDFL	Strong human cohort evidence from 2017 and 2021; MONDO/Orphanet identifier not verified in available evidence
Synonyms	BPTF-related neurodevelopmental disorder; NEDDFL; neurodevelopmental disorder with dysmorphic facies and distal limb anomalies (glinton2021phenotypicexpansionof pages 1-3, zapata2022generationofa pages 1-2)	Exact synonym mapping pending external ontology verification	Strong for naming in literature; formal synonym list incomplete in available context
Evidence source type	Data are aggregated from published human case series/cohorts and model-organism studies, not EHR-derived datasets in the available evidence (stankiewicz2017haploinsufficiencyofthe pages 1-2, zapata2022generationofa pages 1-2)	ECO:0000218 expert assertion supported by traceable author statement (suggested)	Strong for published-source provenance; no registry-scale natural history dataset identified
Causal gene/locus	Causal gene is BPTF on chromosome 17q24.2; disease is associated with heterozygous pathogenic variants and haploinsufficiency (stankiewicz2017haploinsufficiencyofthe pages 1-2)	HGNC:BPTF; UBERON not applicable; Sequence Ontology terms: frameshift_variant, stop_gained, splice_acceptor_variant/splice_donor_variant, inframe_deletion, missense_variant	Strong for gene-disease validity; exact HGNC ID not provided in available context
Protein/complex	BPTF is the largest subunit of the nucleosome remodeling factor (NURF) chromatin-remodeling complex (glinton2021phenotypicexpansionof pages 1-3, zapata2022generationofa pages 1-2)	GO:0006338 chromatin remodeling; GO:0030674 protein-containing complex (general); NURF complex term suggested if curated externally	Strong mechanistic consensus; exact GO complex accession for NURF not verified here
Molecular mechanism	Current best-supported mechanism is BPTF haploinsufficiency causing dysregulated chromatin remodeling and transcription during neurodevelopment (glinton2021phenotypicexpansionof pages 1-3, glinton2021phenotypicexpansionof pages 3-4, stankiewicz2017haploinsufficiencyofthe pages 1-2, zapata2022generationofa pages 1-2)	HP:0000006 Autosomal dominant inheritance; GO:0006357 regulation of transcription by RNA polymerase II; GO:0006338 chromatin remodeling	Strong for loss-of-function/haploinsufficiency; no evidence for protective variants or environmental triggers
Chromatin-reader biology	BPTF binds H3K4me3 through its PHD finger and H4K16ac through its bromodomain, supporting an epigenetic reader/remodeler role (glinton2021phenotypicexpansionof pages 1-3)	GO:0042393 histone binding; GO:0016568 chromatin modification (broad); CHEBI terms for modified histones could be added in curation	Moderate-strong mechanistic evidence; largely inferred from molecular studies summarized in clinical paper
Core phenotype: developmental delay/intellectual disability	Reported in 10/10 individuals in the 2017 cohort and 88% in the 2021 cohort (stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 3-4)	HP:0001263 Global developmental delay; HP:0001249 Intellectual disability	Strong replicated cohort evidence; severity spectrum incompletely quantified
Core phenotype: speech delay	Reported in 10/10 individuals in 2017 and 85% in 2021 (stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 3-4)	HP:0000750 Delayed speech and language development	Strong replicated cohort evidence
Core phenotype: postnatal microcephaly	Reported in 7/9 individuals in 2017; 42% in 2021 cohort summary; 60% microcephaly at assessment in one detailed 2021 extraction; 40% had microcephaly at birth in that extraction (stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 3-4, glinton2021phenotypicexpansionof pages 4-5)	HP:0000252 Microcephaly; HP:0000253 Progressive microcephaly (suggested where postnatal worsening documented)	Strong that microcephaly is common; exact frequency varies with denominator/definition across summaries
Core phenotype: dysmorphic features	Dysmorphic features were present in 9/10 in 2017 and 77% in one 2021 summary; all 20 individuals with available detailed dysmorphology data reportedly had mild dysmorphic features in another 2021 extraction (stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 3-4, glinton2021phenotypicexpansionof pages 4-5)	HP:0001999 Facial dysmorphism; phenotype-specific HPOs may include pointed chin, bulbous nose, prominent nasal ridge	Strong that dysmorphism is common; exact aggregate frequency varies by denominator and ascertainment
Core phenotype: motor delay	Motor delay reported in 69% of 2021 cohort (glinton2021phenotypicexpansionof pages 3-4)	HP:0001270 Motor delay	Moderate-strong; not explicitly quantified in 2017 extraction
Core phenotype: hypotonia	Hypotonia/history of hypotonia reported in 38% of 2021 cohort (glinton2021phenotypicexpansionof pages 3-4, glinton2021phenotypicexpansionof pages 4-5)	HP:0001252 Hypotonia	Moderate-strong cohort evidence
Additional neurologic phenotype: seizures/EEG abnormalities	Seizures/EEG abnormalities were newly emphasized in 2021; 6 patients had seizure history requiring treatment, and 2 had electrographic abnormalities only (glinton2021phenotypicexpansionof pages 4-5, glinton2021phenotypicexpansionof pages 1-3)	HP:0001250 Seizure; HP:0010843 Abnormality of the EEG	Moderate evidence from expanded cohort; 2024 epilepsy-focused paper identified bibliographically but not available in accessible full text
Neuroimaging	In 2021, MRI was normal in 8/13 imaged individuals and mildly abnormal in 5/13, indicating variable and often subtle brain structural findings (glinton2021phenotypicexpansionof pages 4-5, glinton2021phenotypicexpansionof pages 1-3)	HP:0410263 Abnormal brain MRI; UBERON:0000955 brain	Moderate evidence; exact MRI anomaly types not fully extractable from available context
Skeletal/limb phenotype	Distal limb anomalies are part of the syndrome label; reported findings include scoliosis, cutaneous syndactyly, sandal-gap anomalies, limb-length discrepancy, and delayed bone age in some individuals (glinton2021phenotypicexpansionof pages 9-10, glinton2021phenotypicexpansionof pages 1-3)	HP:0001159 Syndactyly; HP:0002650 Scoliosis; HP:0010687 Abnormality of the digits	Moderate evidence; frequencies not fully extractable
Ophthalmologic phenotype	Ophthalmologic complications were reported in the expanded 2021 cohort (glinton2021phenotypicexpansionof pages 1-3)	HP:0000478 Abnormality of the eye	Moderate evidence; exact eye findings and frequencies not fully extractable
Growth phenotype	Short stature occurred in 25%, decreased weight in 53%, and microcephaly/growth restriction were also observed in 2021 extraction (glinton2021phenotypicexpansionof pages 4-5)	HP:0004322 Short stature; HP:0004325 Poor weight gain	Moderate evidence; 2023 growth-hormone report was identified bibliographically but direct outcome details were unavailable
Age at onset/course	Typical onset is congenital/early childhood with neurodevelopmental manifestations recognized in infancy or childhood; published ages ranged from 2.1-13 years in 2017 and 23 months-55 years in 2021, supporting lifelong persistence (stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 3-4)	HP:0003577 Congenital onset; HP:0011463 Childhood onset	Strong for pediatric onset and chronic course; no formal staging system identified
Variant spectrum	2017: 8 loss-of-function and 2 missense variants among 10 unrelated individuals. 2021: 20 distinct variants including 9 frameshift, 4 nonsense, 3 splicing, 2 in-frame deletions, 1 missense, and 1 single-exon deletion; ACMG classes included pathogenic, likely pathogenic, and 2 VUS (stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 3-4)	Sequence Ontology: frameshift_variant, stop_gained, splice_region/splice_donor/splice_acceptor, inframe_deletion, missense_variant, exon_loss_variant	Strong for predominance of truncating variants; exact HGVS list incomplete in accessible evidence
Inheritance	Predominantly autosomal dominant. Initial reports were mostly de novo; 2021 provided first non-mosaic affected-parent transmissions, showing inherited causative variants also occur (glinton2021phenotypicexpansionof pages 3-4, stankiewicz2017haploinsufficiencyofthe pages 1-2)	HP:0000006 Autosomal dominant inheritance; HP:0025352 De novo mutation (suggested annotation at variant level)	Strong for AD inheritance with variable expressivity; penetrance not quantified
Penetrance/expressivity	Expressivity appears variable, with milder phenotypes noted especially for some missense/inherited cases; penetrance remains not established from available data (glinton2021phenotypicexpansionof pages 12-13, glinton2021phenotypicexpansionof pages 3-4)	HP:0003828 Variable expressivity	Moderate evidence for variability; penetrance unknown
Population/epidemiology	No reliable prevalence or incidence estimates were identified in the available evidence; published literature consists of rare case series/families (stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 3-4)	Orphan disease; MONDO/Orphanet prevalence pending verification	Major evidence gap
Sex distribution	2021 cohort included 14 males and 11 females in the extracted summary, arguing against a strong sex-limited pattern (glinton2021phenotypicexpansionof pages 3-4)	PATO sex terms not necessary	Moderate evidence; one extracted count sums to 25 despite cohort described as 26, indicating source-summary inconsistency
Diagnostics: clinical	Diagnosis is suspected from syndromic NDD with speech delay, microcephaly, dysmorphic facies, and distal limb anomalies, with supportive MRI/EEG findings when present (glinton2021phenotypicexpansionof pages 1-3, glinton2021phenotypicexpansionof pages 4-5, stankiewicz2017haploinsufficiencyofthe pages 1-2)	HPO set above; NCIT:C159866 Genetic Testing (broad suggested term)	Strong for phenotype-guided suspicion; no formal consensus clinical criteria identified
Diagnostics: genetic testing	WES and chromosomal microarray were used in the landmark cohort; later cohorts identified sequence variants and single-exon deletions, supporting exome/genome sequencing plus CNV analysis as useful approaches (stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 4-5)	NCIT:C101294 Whole Exome Sequencing; NCIT:C63420 Comparative Genomic Hybridization/array-based CNV analysis (suggested broad mapping)	Strong practical evidence from case ascertainment; no disease-specific testing guideline located
Functional/omics diagnostics	2021 authors noted lack of well-validated functional assays and suggested RNA-seq or proteomics may have diagnostic utility for difficult variants such as missense changes (glinton2021phenotypicexpansionof pages 12-13)	NCIT:C153191 RNA Sequencing; NCIT:C20085 Proteomic Profiling (suggested)	Hypothesis-level/author opinion rather than established clinical standard
Differential diagnosis	Differential includes other syndromic neurodevelopmental disorders/chromatinopathies and cases initially labeled as other growth syndromes; one cited 2019 adult case had initially been diagnosed with Silver-Russell syndrome (glinton2021phenotypicexpansionof pages 13-13)	Broad category: chromatinopathy	Limited direct evidence in available context
Treatment/supportive care	No disease-modifying therapy is established. Reported management is supportive and symptom-directed: developmental therapies, educational support, seizure management, and routine multidisciplinary surveillance (inferred from seizure treatments and chronic NDD features) (glinton2021phenotypicexpansionof pages 4-5)	NCIT:C15604 Supportive Care; NCIT:C21072 Physical Therapy; NCIT:C17733 Occupational Therapy; NCIT:C12453 Speech Therapy	Moderate evidence for supportive approach; formal treatment algorithms absent
Seizure treatment examples	Reported anti-seizure interventions in 2021 cohort included sodium valproate, levetiracetam, and vagal nerve stimulator use in individual patients (glinton2021phenotypicexpansionof pages 4-5)	NCIT:C29511 Sodium Valproate; NCIT:C1570 Levetiracetam; NCIT:C99939 Vagus Nerve Stimulation	Case-level evidence only; no response rates or syndrome-specific efficacy data
Growth hormone	A 2023 report on growth hormone treatment in children with novel BPTF variants was identified bibliographically but not accessible in full text here, so efficacy/safety cannot be reliably summarized (from search history noted in conversation)	NCIT:C1772 Somatropin/Growth Hormone (if later curated)	Explicit evidence gap in accessible corpus
Prognosis/outcomes	Available evidence suggests a chronic lifelong neurodevelopmental disorder with survival into adulthood documented (age up to 55 years in 2021 cohort), but no formal survival, mortality, or quality-of-life statistics were identified (glinton2021phenotypicexpansionof pages 3-4)	ICF/quality-of-life terms could be added later	Major gap: no natural-history or mortality study found
Environmental factors	No established environmental, infectious, lifestyle, or protective factors were identified; disease is currently understood as primarily Mendelian/genetic (stankiewicz2017haploinsufficiencyofthe pages 1-2, zapata2022generationofa pages 1-2)	Not established	Strong negative statement based on absence in current literature context
Gene-environment interaction	No BPTF-specific gene-environment interaction data were identified (stankiewicz2017haploinsufficiencyofthe pages 1-2, zapata2022generationofa pages 1-2)	Not established	Evidence gap
Primary anatomy	Central nervous system/brain, especially forebrain and cerebral cortex, are the primary affected structures based on human phenotype and mouse modeling (zapata2022generationofa pages 1-2)	UBERON:0000955 brain; UBERON:0001890 cerebral cortex; UBERON:0001891 telencephalon/forebrain suggested	Strong convergent human/model evidence
Cell types implicated	Neural progenitor cells and cortical neurons are implicated; mouse data show prolonged progenitor cell cycle, reduced neuronal output, and impaired deep-layer neuron maturation including Ctip2+ neurons (zapata2022generationofa pages 1-2)	CL:0011115 neural progenitor cell (suggested); CL:0000540 neuron; CL:cortical neuron/deep-layer cortical projection neuron suggested	Strong model evidence; exact CL IDs for all cortical subtypes should be curator-verified
Cellular processes	Upstream defect involves impaired chromatin remodeling/transcriptional regulation; downstream effects include prolonged progenitor cell cycle, apoptosis, disrupted neuronal fate specification, cortical lamination defects, and reduced neuronal maturation (zapata2022generationofa pages 1-2)	GO:0006338 chromatin remodeling; GO:0051301 cell division; GO:0006915 apoptotic process; GO:0022008 neurogenesis; GO:0007417 central nervous system development; GO:0007399 nervous system development	Strong mouse mechanistic evidence; direct human tissue confirmation lacking
Subcellular localization	Disease mechanism is centered in the nucleus/chromatin compartment, consistent with a chromatin-remodeling transcription factor (glinton2021phenotypicexpansionof pages 1-3, zapata2022generationofa pages 1-2)	GO:0005634 nucleus; GO:0000785 chromatin	Strong general mechanistic inference
Molecular profiling	Mouse forebrain RNA-seq identified altered expression of fate-determining transcription factors and pathways related to neural development, apoptotic signaling, and amino acid biosynthesis; dysregulated genes were enriched for Myc binding sites (zapata2022generationofa pages 1-2)	GO:0009880 embryonic pattern specification; GO:0043066 negative regulation of apoptotic process/related apoptosis terms; GO:0008652 cellular amino acid biosynthetic process	Strong model evidence; no human transcriptomic signature established
Expert mechanistic interpretation	Available studies support a causal chain from BPTF loss-of-function to NURF dysfunction, altered chromatin accessibility/transcription in developing cortex, reduced progenitor fitness and neuronal specification, then microcephaly/intellectual disability/speech delay (glinton2021phenotypicexpansionof pages 1-3, zapata2022generationofa pages 1-2)	Pathway annotation can center on chromatin remodeling and corticogenesis	Strong synthesis from human genetics plus mouse model
Animal model: zebrafish	CRISPR/Cas9 F0 zebrafish bptf disruption caused reduced head size, increased apoptosis, altered proliferation, and abnormal craniofacial patterning (stankiewicz2017haploinsufficiencyofthe pages 1-2)	NCBITaxon:7955 Danio rerio	Strong experimental support for developmental role; F0 mosaic model limitations
Animal model: mouse	Forebrain-specific Bptf conditional knockout mice were viable to adulthood but smaller and showed severe cortical hypoplasia, prolonged progenitor cell cycle, high cell death, disrupted cortical lamination, reduced deep-layer neurons, and neuronal maturation defects (zapata2022generationofa pages 1-2)	NCBITaxon:10090 Mus musculus	Strong disease-relevant mechanistic model; conditional knockout is more severe than human heterozygous state
Natural disease in other species	No naturally occurring veterinary BPTF-related disorder was identified in available evidence (stankiewicz2017haploinsufficiencyofthe pages 1-2, zapata2022generationofa pages 1-2)	Not established	Evidence gap
Clinical trials	No disease-specific interventional clinical trials were identified in the available search results (clinical trial search in conversation)	Not established	Evidence gap
Prevention/genetic counseling	Prevention is limited to reproductive/genetic counseling, with recurrence risk depending on whether a variant is de novo or inherited from an affected parent; cascade testing may be relevant once a familial variant is known (glinton2021phenotypicexpansionof pages 3-4)	NCIT:C15280 Genetic Counseling	Moderate evidence from inheritance data; no formal counseling guideline identified
Unknown/not established fields	Prevalence, incidence, penetrance, founder effects, carrier frequency, environmental modifiers, protective factors, standardized diagnostic criteria, prognostic biomarkers, disease-specific QoL measures, and targeted molecular therapies are not established in the available evidence (stankiewicz2017haploinsufficiencyofthe pages 1-2, glinton2021phenotypicexpansionof pages 12-13, glinton2021phenotypicexpansionof pages 3-4)	Mark as unknown/not established in KB	Important to preserve as explicit negatives/gaps rather than infer unsupported claims

Table: This table summarizes knowledge-base-ready findings for BPTF-related neurodevelopmental disorder/NEDDFL, including core phenotypes, mechanism, diagnostics, inheritance, and model evidence. It also flags important unknowns and limitations where the available evidence is sparse or unverified.

Critical data gaps

The following should remain explicitly unknown/not established in a production knowledge base: disease-specific MONDO and Orphanet identifiers unless separately verified; prevalence and incidence; penetrance; ancestry or geographic effects; founder variants; quantitative quality of life; standardized diagnostic criteria; longitudinal natural history; life expectancy; prognostic biomarkers; validated episignature; human single-cell/spatial/multi-omics profiles; treatment response rates; and disease-modifying or preventive therapy. Apparent precision beyond the small published cohorts would be misleading.

References

(glinton2021phenotypicexpansionof pages 1-3): Kevin E. Glinton, Anna C. E. Hurst, Kevin M. Bowling, Ingrid Cristian, Devon Haynes, Dusit Adstamongkonkul, Oskar Schnappauf, David B. Beck, Carole Brewer, Aditi Shah Parikh, Deepali N. Shinde, Alan Donaldson, Ariel Brautbar, Saskia Koene, Arie van Haeringen, Amélie Piton, Yline Capri, Margherita Furlan, Elena Gardella, Rikke Steensbjerre Møller, Irma van de Beek, Linda Zuurbier, Phillis Lakeman, Allan Bayat, Julian Martinez, Rebecca Signer, Pernille M. Torring, Morten Buch Engelund, Karen W. Gripp, Louise Amlie‐Wolf, Lindsay B. Henderson, Alina T. Midro, Eugeniusz Tarasów, Beata Stasiewicz‐Jarocka, Diana Moskal‐Jasinska, Paul Vos, Felix Boschann, Corinna Stoltenburg, Oliver Puk, Inger‐Lise Mero, Kristine Lossius, Cyril Mignot, Boris Keren, Johanna C. Acosta Guio, Ignacio Briceño, Alberto Gomez, Yaping Yang, and Pawel Stankiewicz. Phenotypic expansion of the bptf‐related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies. American Journal of Medical Genetics. Part a, 185:1366-1378, Jan 2021. URL: https://doi.org/10.1002/ajmg.a.62102, doi:10.1002/ajmg.a.62102. This article has 33 citations and is from a peer-reviewed journal.
(stankiewicz2017haploinsufficiencyofthe pages 1-2): Paweł Stankiewicz, Tahir N. Khan, Przemyslaw Szafranski, Leah Slattery, Haley Streff, Francesco Vetrini, Jonathan A. Bernstein, Chester W. Brown, Jill A. Rosenfeld, Surya Rednam, Sarah Scollon, Katie L. Bergstrom, Donald W. Parsons, Sharon E. Plon, Marta W. Vieira, Caio R.D.C. Quaio, Wagner A.R. Baratela, Johanna C. Acosta Guio, Ruth Armstrong, Sarju G. Mehta, Patrick Rump, Rolph Pfundt, Raymond Lewandowski, Erica M. Fernandes, Deepali N. Shinde, Sha Tang, Juliane Hoyer, Christiane Zweier, André Reis, Carlos A. Bacino, Rui Xiao, Amy M. Breman, Janice L. Smith, Nicholas Katsanis, Bret Bostwick, Bernt Popp, Erica E. Davis, and Yaping Yang. Haploinsufficiency of the chromatin remodeler bptf causes syndromic developmental and speech delay, postnatal microcephaly, and dysmorphic features. American journal of human genetics, 101 4:503-515, Oct 2017. URL: https://doi.org/10.1016/j.ajhg.2017.08.014, doi:10.1016/j.ajhg.2017.08.014. This article has 113 citations and is from a highest quality peer-reviewed journal.
(glinton2021phenotypicexpansionof pages 3-4): Kevin E. Glinton, Anna C. E. Hurst, Kevin M. Bowling, Ingrid Cristian, Devon Haynes, Dusit Adstamongkonkul, Oskar Schnappauf, David B. Beck, Carole Brewer, Aditi Shah Parikh, Deepali N. Shinde, Alan Donaldson, Ariel Brautbar, Saskia Koene, Arie van Haeringen, Amélie Piton, Yline Capri, Margherita Furlan, Elena Gardella, Rikke Steensbjerre Møller, Irma van de Beek, Linda Zuurbier, Phillis Lakeman, Allan Bayat, Julian Martinez, Rebecca Signer, Pernille M. Torring, Morten Buch Engelund, Karen W. Gripp, Louise Amlie‐Wolf, Lindsay B. Henderson, Alina T. Midro, Eugeniusz Tarasów, Beata Stasiewicz‐Jarocka, Diana Moskal‐Jasinska, Paul Vos, Felix Boschann, Corinna Stoltenburg, Oliver Puk, Inger‐Lise Mero, Kristine Lossius, Cyril Mignot, Boris Keren, Johanna C. Acosta Guio, Ignacio Briceño, Alberto Gomez, Yaping Yang, and Pawel Stankiewicz. Phenotypic expansion of the bptf‐related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies. American Journal of Medical Genetics. Part a, 185:1366-1378, Jan 2021. URL: https://doi.org/10.1002/ajmg.a.62102, doi:10.1002/ajmg.a.62102. This article has 33 citations and is from a peer-reviewed journal.
(zapata2022generationofa pages 1-2): Gerardo Zapata, Keqin Yan, and David J Picketts. Generation of a mouse model of the neurodevelopmental disorder with dysmorphic facies and distal limb anomalies (neddfl) syndrome. Human molecular genetics, 31:3405-3421, May 2022. URL: https://doi.org/10.1093/hmg/ddac119, doi:10.1093/hmg/ddac119. This article has 14 citations and is from a domain leading peer-reviewed journal.
(glinton2021phenotypicexpansionof pages 12-13): Kevin E. Glinton, Anna C. E. Hurst, Kevin M. Bowling, Ingrid Cristian, Devon Haynes, Dusit Adstamongkonkul, Oskar Schnappauf, David B. Beck, Carole Brewer, Aditi Shah Parikh, Deepali N. Shinde, Alan Donaldson, Ariel Brautbar, Saskia Koene, Arie van Haeringen, Amélie Piton, Yline Capri, Margherita Furlan, Elena Gardella, Rikke Steensbjerre Møller, Irma van de Beek, Linda Zuurbier, Phillis Lakeman, Allan Bayat, Julian Martinez, Rebecca Signer, Pernille M. Torring, Morten Buch Engelund, Karen W. Gripp, Louise Amlie‐Wolf, Lindsay B. Henderson, Alina T. Midro, Eugeniusz Tarasów, Beata Stasiewicz‐Jarocka, Diana Moskal‐Jasinska, Paul Vos, Felix Boschann, Corinna Stoltenburg, Oliver Puk, Inger‐Lise Mero, Kristine Lossius, Cyril Mignot, Boris Keren, Johanna C. Acosta Guio, Ignacio Briceño, Alberto Gomez, Yaping Yang, and Pawel Stankiewicz. Phenotypic expansion of the bptf‐related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies. American Journal of Medical Genetics. Part a, 185:1366-1378, Jan 2021. URL: https://doi.org/10.1002/ajmg.a.62102, doi:10.1002/ajmg.a.62102. This article has 33 citations and is from a peer-reviewed journal.
(glinton2021phenotypicexpansionof pages 4-5): Kevin E. Glinton, Anna C. E. Hurst, Kevin M. Bowling, Ingrid Cristian, Devon Haynes, Dusit Adstamongkonkul, Oskar Schnappauf, David B. Beck, Carole Brewer, Aditi Shah Parikh, Deepali N. Shinde, Alan Donaldson, Ariel Brautbar, Saskia Koene, Arie van Haeringen, Amélie Piton, Yline Capri, Margherita Furlan, Elena Gardella, Rikke Steensbjerre Møller, Irma van de Beek, Linda Zuurbier, Phillis Lakeman, Allan Bayat, Julian Martinez, Rebecca Signer, Pernille M. Torring, Morten Buch Engelund, Karen W. Gripp, Louise Amlie‐Wolf, Lindsay B. Henderson, Alina T. Midro, Eugeniusz Tarasów, Beata Stasiewicz‐Jarocka, Diana Moskal‐Jasinska, Paul Vos, Felix Boschann, Corinna Stoltenburg, Oliver Puk, Inger‐Lise Mero, Kristine Lossius, Cyril Mignot, Boris Keren, Johanna C. Acosta Guio, Ignacio Briceño, Alberto Gomez, Yaping Yang, and Pawel Stankiewicz. Phenotypic expansion of the bptf‐related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies. American Journal of Medical Genetics. Part a, 185:1366-1378, Jan 2021. URL: https://doi.org/10.1002/ajmg.a.62102, doi:10.1002/ajmg.a.62102. This article has 33 citations and is from a peer-reviewed journal.
(glinton2021phenotypicexpansionof pages 9-10): Kevin E. Glinton, Anna C. E. Hurst, Kevin M. Bowling, Ingrid Cristian, Devon Haynes, Dusit Adstamongkonkul, Oskar Schnappauf, David B. Beck, Carole Brewer, Aditi Shah Parikh, Deepali N. Shinde, Alan Donaldson, Ariel Brautbar, Saskia Koene, Arie van Haeringen, Amélie Piton, Yline Capri, Margherita Furlan, Elena Gardella, Rikke Steensbjerre Møller, Irma van de Beek, Linda Zuurbier, Phillis Lakeman, Allan Bayat, Julian Martinez, Rebecca Signer, Pernille M. Torring, Morten Buch Engelund, Karen W. Gripp, Louise Amlie‐Wolf, Lindsay B. Henderson, Alina T. Midro, Eugeniusz Tarasów, Beata Stasiewicz‐Jarocka, Diana Moskal‐Jasinska, Paul Vos, Felix Boschann, Corinna Stoltenburg, Oliver Puk, Inger‐Lise Mero, Kristine Lossius, Cyril Mignot, Boris Keren, Johanna C. Acosta Guio, Ignacio Briceño, Alberto Gomez, Yaping Yang, and Pawel Stankiewicz. Phenotypic expansion of the bptf‐related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies. American Journal of Medical Genetics. Part a, 185:1366-1378, Jan 2021. URL: https://doi.org/10.1002/ajmg.a.62102, doi:10.1002/ajmg.a.62102. This article has 33 citations and is from a peer-reviewed journal.
(glinton2021phenotypicexpansionof pages 13-13): Kevin E. Glinton, Anna C. E. Hurst, Kevin M. Bowling, Ingrid Cristian, Devon Haynes, Dusit Adstamongkonkul, Oskar Schnappauf, David B. Beck, Carole Brewer, Aditi Shah Parikh, Deepali N. Shinde, Alan Donaldson, Ariel Brautbar, Saskia Koene, Arie van Haeringen, Amélie Piton, Yline Capri, Margherita Furlan, Elena Gardella, Rikke Steensbjerre Møller, Irma van de Beek, Linda Zuurbier, Phillis Lakeman, Allan Bayat, Julian Martinez, Rebecca Signer, Pernille M. Torring, Morten Buch Engelund, Karen W. Gripp, Louise Amlie‐Wolf, Lindsay B. Henderson, Alina T. Midro, Eugeniusz Tarasów, Beata Stasiewicz‐Jarocka, Diana Moskal‐Jasinska, Paul Vos, Felix Boschann, Corinna Stoltenburg, Oliver Puk, Inger‐Lise Mero, Kristine Lossius, Cyril Mignot, Boris Keren, Johanna C. Acosta Guio, Ignacio Briceño, Alberto Gomez, Yaping Yang, and Pawel Stankiewicz. Phenotypic expansion of the bptf‐related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies. American Journal of Medical Genetics. Part a, 185:1366-1378, Jan 2021. URL: https://doi.org/10.1002/ajmg.a.62102, doi:10.1002/ajmg.a.62102. This article has 33 citations and is from a peer-reviewed journal.

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Classifications

Inheritance

Discussions and Knowledge Gaps

Pathophysiology

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Phenotypes

Genetic Associations

Medical Actions

Diagnosis

Prevalence

Differential Diagnoses

Animal Models

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BPTF-Related Neurodevelopmental Disorder: Comprehensive Disease-Characteristics Report

Executive summary and evidence limits

1. Disease information

Definition and nomenclature

Identifiers

2. Etiology

Causal factor

Genetic risk

Environmental and protective factors

3. Phenotypes

Neurodevelopmental and neurologic features

Growth, craniofacial, skeletal, and ocular features

Behavioral, laboratory, and quality-of-life data

4. Genetic and molecular information

Gene and variant spectrum

Functional consequence and epigenetics

5. Environmental information

6. Mechanism and pathophysiology

Causal chain

Suggested functional ontology

Molecular profiling and advanced technologies

7. Anatomical structures affected

8. Temporal development

9. Inheritance and population

10. Diagnostics

Recommended genomic approach

Clinical evaluation after diagnosis

Differential diagnosis

11. Outcome and prognosis

12. Treatment and real-world implementation

13. Prevention

14. Other species and natural disease

15. Model organisms

Zebrafish

Mouse

Recent research and authoritative interpretation

Key primary sources and abstract quotations

Knowledge-base-ready summary

Critical data gaps

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