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Classifications

Harrison's Chapter

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Inheritance

1

Autosomal Dominant HP:0000006

Heterozygous ABL1 missense alleles act dominantly. Most reported probands carry de novo variants, but vertical transmission from an affected parent to an affected child has been documented for the recurrent p.Tyr245Cys allele, establishing cosegregation rather than de novo occurrence alone. Expressivity is variable - stature, for example, ranges from short to tall within the same molecular condition - and numerical penetrance cannot be estimated from the small published pedigrees.

Autosomal dominant inheritance Expressivity: VARIABLE

Show evidence (3 references)

PMID:28288113 SUPPORT Human Clinical

"Here we report ABL1 germline variants cosegregating with an autosomal dominant disorder characterized by congenital heart disease, skeletal abnormalities, and failure to thrive."

Original report establishing autosomal dominant inheritance with cosegregation.

PMID:28288113 SUPPORT Human Clinical

"Sanger sequencing of asymptomatic parents of the probands in families 1 and 2 was negative for p.Tyr245Cys, indicating the variant arose de novo in the probands. Subject 1's similarly affected daughter was found to have inherited the heterozygous p.Tyr245Cys substitution. In family 3,..."

Documents both de novo occurrence and parent-to-child transmission of the same allele.

PMID:33223528 SUPPORT Human Clinical

"Interestingly, two individuals have tall stature, in contrast to short stature in the majority of cases."

Illustrates variable expressivity across carriers of pathogenic ABL1 alleles.

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Discussions and Knowledge Gaps

3

Through which developmental cell lineages and downstream effectors does ABL1 kinase hyperactivity produce the specific CHDSKM malformation set (cardiac septa and outflow tract, digits, axial skeleton, aortic root)?

KNOWLEDGE GAP OPEN chdskm_lineage_route_to_malformation

Attached to

pathophysiology#Increased Substrate Tyrosine Phosphorylation pathophysiology#Disrupted Cardiac Septation and Outflow Tract Development

Steps 1 to 3 of the causal chain - autoinhibition loss, kinase hyperactivity, increased substrate phosphorylation - are experimentally solid and independently replicated. The step from generalised phosphotyrosine excess to a specific, reproducible malformation pattern is entirely inferential. The only concrete effector nominations come from a single phosphoproteomic experiment in a transfected cell line (UFD1, AXIN1, ATRX), and even the cell types involved - cardiomyocytes, endocardial and valvular interstitial cells, cardiac neural crest derivatives, chondrocytes, craniofacial mesenchyme - remain plausible candidates rather than demonstrated targets. This is why the pathophysiology edges leading out of the phosphorylation node are typed INDIRECT_UNKNOWN_INTERMEDIATES and why no cell types are asserted on the cardiac node.

Proposed experiments

Lineage-restricted CHDSKM allele knock-in in mouse

chdskm_lineage_restricted_knockin

Conditional knock-in of a recurrent human allele (p.Tyr245Cys or p.Glu528Lys) restricted to cardiac mesoderm, cardiac neural crest, endocardium, and limb/skeletal mesenchyme, with staged phenotyping of septation and outflow tract development.

Decision criterion

A lineage in which the knock-in reproduces septal or outflow tract defects identifies the cell population through which kinase hyperactivity acts.

Phosphoproteomics in disease-relevant differentiated cell types

chdskm_ipsc_lineage_phosphoproteomics

Differentiate patient-derived iPSCs to cardiomyocytes and chondrocytes and repeat phosphoproteomic profiling in those lineages rather than in HEK293T, testing whether UFD1, AXIN1, and ATRX hyperphosphorylation reproduces outside the overexpression system.

Decision criterion

Reproduction of the effector hyperphosphorylation in a developmentally relevant lineage would upgrade those nominations from hypothesis to candidate mechanism.

Show evidence (1 reference)

PMID:33075386 PARTIAL In Vitro

"AXIN1 and ATRX may be important in elucidating the mechanisms of other phenotypes, such as finger contracture and failure to thrive. Verification of these hypotheses would lead to further understanding of the pathophysiology and the development of treatment methods."

The authors explicitly frame the effector assignments as unverified hypotheses requiring further work.

Do the available Abl1 mouse models, which are all loss-of-function, have any translational validity for a human heterozygous gain-of-function syndrome?

HUMAN MODEL MISMATCH OPEN chdskm_model_organism_mismatch

Attached to

pathophysiology#ABL1 Autoinhibitory Regulatory Core Disruption

Every published Abl1 mouse model is a null or truncation allele. Their phenotypes - growth delay, cardiac hyperplasia, osteoporosis, lymphopenia, perinatal lethality - establish that ABL1 matters in development but point in the opposite functional direction from the human disease. The mismatch is not incidental: the original authors specifically re-examined ventricular wall thickness in their patients and confirmed the absence of the cardiac hyperplasia seen in the knockout mice, attributing the difference to increased versus abolished kinase activity. Mouse heterozygotes are largely unaffected, so there is no dosage model either. No knock-in model of a recurrent human CHDSKM allele has been reported.

Proposed experiments

CHDSKM knock-in mouse compared against Abl1 null

chdskm_knockin_versus_null

Generate constitutive and conditional knock-in mice carrying the human p.Tyr245Cys or p.Glu528Lys allele, assess whether cardiac septal defects, digital contractures, growth restriction, and aortic root dilatation are recapitulated, and compare directly against Abl1 null animals in the same genetic background.

Decision criterion

Recapitulation of the human malformation set by the knock-in, with a phenotype distinct from the null, would establish a valid model and confirm the functional direction of the human alleles.

Show evidence (2 references)

PMID:28288113 SUPPORT Model Organism

"Abl1 knockout mice have growth delay, cardiac hyperplasia and osteoporosis"

Describes the loss-of-function mouse phenotype available as a model.

PMID:28288113 REFUTE Human Clinical

"We re-evaluated the ventricular wall thickness of our patients and confirmed that there is no cardiac hyperplasia"

Explicitly documents that the mouse cardiac phenotype is not reproduced in human patients - the core of the model mismatch.

Do germline ABL1 gain-of-function alleles confer an increased lifetime risk of haematological or other malignancy?

KNOWLEDGE GAP OPEN chdskm_malignancy_risk

Attached to

pathophysiology#Constitutive ABL1 Tyrosine Kinase Hyperactivity

ABL1 is a proto-oncogene and its constitutive activation in the somatic BCR::ABL1 fusion drives chronic myeloid leukaemia, so a germline activating allele raises an obvious question. No malignancy has been reported in any CHDSKM patient, but the total described cohort is very small and mostly young, so absence of events is weak evidence of absence of risk. There is a mechanistic argument for reassurance - disruption of myristoyl binding alone may not activate ABL1 enough to drive malignancy because two other autoinhibitory linchpins remain intact, whereas BCR::ABL1 loses both the myristoyl group and the N-terminal brace - but this is reasoning, not data. Notably, the authors of the largest functional series report that none of the activating germline variants they describe has been associated with somatic tyrosine kinase inhibitor resistance in leukaemia - though one residue, Ala452, is shared between the germline and somatic settings, so the separation is not absolute.

Proposed experiments

Longitudinal CHDSKM malignancy registry

chdskm_longitudinal_registry

Establish a prospective registry capturing routine blood counts and malignancy events in molecularly confirmed CHDSKM patients into adulthood, alongside aortic dimensions, hearing, growth, and neurodevelopment.

Decision criterion

Accumulated person-years without haematological malignancy, or an excess of events, would for the first time bound the lifetime risk.

Transformation capacity of germline-allele haematopoietic cells

chdskm_hspc_transformation_assay

Assess whether patient-derived or engineered haematopoietic stem and progenitor cells carrying the germline CHDSKM alleles show clonal advantage or transformation capacity relative to BCR::ABL1-expressing controls.

Decision criterion

Absence of clonal advantage would support the mechanistic argument that myristoyl-pocket disruption alone is insufficient for transformation.

Show evidence (2 references)

PMID:33223528 PARTIAL Human Clinical

"No patients with the ABL1 skeletal and cardiac malformation syndrome described here or elsewhere are reported to have haematological malignancy, but longitudinal follow up of these patients will be required to better determine this."

States both the absence of observed malignancy and the insufficiency of current follow-up.

PMID:28288113 PARTIAL Human Clinical

"Malignancies have not been detected in any of the affected individuals with ABL1 germline variants, but as they cause increased phosphorylation and possibly increased kinase activity of this proto-oncogene, it may be prudent to perform systematic clinical screening for ABL1-associated cancers in..."

The original authors' recommendation for cancer screening in the face of unquantified risk.

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Pathophysiology

7

ABL1 Autoinhibitory Regulatory Core Disruption

Wild-type ABL1 is held in a low-activity state by an assembled SH3-SH2-kinase regulatory core. Three intramolecular "linchpins" enforce this: docking of the SH3 domain onto the SH2-kinase linker, insertion of the N-terminal myristoyl group of isoform 1b into a pocket in the kinase domain, and an N-terminal brace over the SH3-SH2 unit. The CHDSKM missense substitutions whose position has been mapped fall in these regulatory elements - four of the five alleles in the largest functionally characterised series lie in the myristoyl-binding pocket, with others in the SH2-kinase linker and the C-terminal alpha-I helix - and destabilise the assembled core. Several later-reported alleles (p.Trp67Arg, p.Thr136Met, p.Gln300Glu, p.Ile508Leu) have not been assigned to a defined autoinhibitory element by their source reports, so the clustering claim is scoped to the characterised alleles. This is the same autoinhibition failure that the somatic BCR::ABL1 fusion achieves by deleting the myristoylated N-terminus, which is why the two conditions share a molecular logic while remaining entirely distinct diseases.

ABL1 hgnc:76

ABL1 non-receptor tyrosine kinase activity GO:0004715 ↑ INCREASED

Downstream

Constitutive ABL1 Tyrosine Kinase Hyperactivity Loss of autoinhibition is the direct cause of the elevated kinase activity, not merely a correlate: the same variants that disrupt the regulatory elements are the ones that raise catalytic output.

Show evidence (4 references)

PMID:33223528 SUPPORT Computational

"Four of the variants cluster in the myristoyl-binding pocket of ABL1, a region critical for auto-inhibitory regulation of the kinase domain."

Establishes the myristoyl-binding pocket as the mutational hotspot of the four functionally characterised alleles in that series. Tagged COMPUTATIONAL because the clustering is an in silico mapping of patient variants onto the autoinhibited ABL1 crystal structure (PDB 1OPL), combined with missense-constraint and conservation analysis, rather than a clinical or wet-lab observation.

PMID:33223528 SUPPORT In Vitro

"Our analysis supports an ABL1 gain-of-function mechanism due to loss of auto-inhibition, and demonstrates the potential for pharmacological inhibition using imatinib."

States the loss-of-autoinhibition gain-of-function mechanism directly.

PMID:33223528 SUPPORT Other

"As the N-terminus of ABL1 is lost in the fusion product, the auto-inhibitory binding of the myristoyl group to the kinase domain is abolished, and ABL1 gains constitutive tyrosine kinase activity which drives cellular proliferation"

Describes the shared autoinhibition-failure logic with BCR::ABL1, the mechanistic parallel that motivates the germline gain-of-function model.

+ 1 more reference

Constitutive ABL1 Tyrosine Kinase Hyperactivity

With autoinhibition relieved, the mutant kinase is catalytically more active than wild type. This has been demonstrated repeatedly and independently: by transient transfection of HEK293T cells with each of the reported disease alleles, and by purified-protein biophysics for the alpha-I-helix allele p.Glu528Lys. Crucially, the increased activity is pharmacologically suppressible - imatinib abolished the excess phosphorylation across all tested constructs in vitro, which is the entire (preclinical) basis for interest in ABL-directed tyrosine kinase inhibitors in this syndrome.

ABL1 autophosphorylation at Tyr245 (allele-dependent direction; increased for myristoyl-pocket alleles, reduced for the SH2-kinase-linker alleles p.Val244Ala and p.Tyr245Cys, which activate the kinase independently of Tyr245 phosphorylation status) GO:0038083

ABL1 tyrosine kinase catalytic activity GO:0004715 ↑ INCREASED

Downstream

Increased Substrate Tyrosine Phosphorylation The elevated kinase activity is measured as, and therefore directly produces, increased phosphorylation of ABL1 substrates. The edge is reversible in vitro: inhibiting the kinase removes the substrate phosphorylation.

Show evidence (3 references)

PMID:28288113 SUPPORT In Vitro

"We overexpressed the mutant constructs in HEK 293T cells and observed increased tyrosine phosphorylation, suggesting increased ABL1 kinase activities associated with both the p.Tyr245Cys and p.Ala356Thr substitutions."

Original functional demonstration of increased kinase activity for both founding alleles.

PMID:33223528 SUPPORT In Vitro

"Functional work to investigate ABL1 kinase activity in vitro by transient transfection of HEK293T cells with variant ABL1 plasmid constructs revealed increased phosphorylation of ABL1-specific substrates compared to wild-type. The increased tyrosine kinase activity was suppressed by imatinib..."

Independent replication across four further alleles, plus the imatinib-suppressibility that underpins the ABL-inhibitor hypothesis.

PMID:32643838 SUPPORT In Vitro

"Functional investigation of the three novel variants showed an increased ABL1 kinase activity."

Third independent laboratory confirming increased kinase activity for new alleles.

Increased Substrate Tyrosine Phosphorylation

Hyperactive ABL1 raises global cellular phosphotyrosine and specifically hyperphosphorylates canonical ABL1 substrates, of which STAT5/STAT5B is the best-characterised readout across all three functional studies. An unbiased phosphoproteomic survey of one patient-derived allele additionally found increased phosphorylation of UFD1, AXIN1, and ATRX, nominating candidate effectors that could link kinase hyperactivity to the cardiac, digital, and growth phenotypes - notably UFD1, which the authors relate to the cardiac phenotype of 22q11.2 deletion syndrome. These effector assignments are hypotheses generated in a cell line, not validated patient-tissue mechanisms.

peptidyl-tyrosine phosphorylation GO:0018108 ↑ INCREASED STAT5 tyrosine phosphorylation GO:0007260 ↑ INCREASED

Downstream

Disrupted Cardiac Septation and Outflow Tract Development

Disrupted Skeletal and Connective Tissue Morphogenesis

Impaired Prenatal and Postnatal Growth

Show evidence (3 references)

PMID:28288113 SUPPORT In Vitro

"Overexpression of the mutant constructs in both isoforms resulted in increased overall phosphotyrosine (p-Tyr) and increased phosphorylation of specific ABL1 substrates (STAT5) when compared to wild-type"

Establishes increased global phosphotyrosine and STAT5 phosphorylation as the cellular readout.

PMID:33075386 SUPPORT In Vitro

"Western blotting confirmed that tyrosine phosphorylation in STAT5, a substrate of ABL1, was enhanced, and the novel mutation was proved to be a gain-of-function mutation."

Independent confirmation of STAT5 hyperphosphorylation for a further patient allele.

PMID:33075386 PARTIAL In Vitro

"The proteome analysis showed that phosphorylation in proteins such as UFD1, AXIN1, ATRX, which may be involved in the phenotypes, was enhanced in the mutant group."

Nominates candidate downstream effectors; the authors themselves frame these as hypotheses ("may be involved"), so this supports the node only partially.

Disrupted Cardiac Septation and Outflow Tract Development

Dysregulated ABL1 signalling during cardiac morphogenesis produces structural heart disease in the great majority of patients. The reported lesions are concentrated at the septa and the left and right outflow tracts: atrial and ventricular septal defects, patent ductus arteriosus, supravalvular pulmonary stenosis, bicuspid aortic valve, and aortic root dilatation. The specific developmental lineage through which kinase hyperactivity produces these defects has not been established; the phosphoproteomic nomination of UFD1, the 22q11.2 cardiac gene, is the only concrete candidate link so far.

cardiac septum morphogenesis GO:0060411 ⚠ ABNORMAL ventricular septum development GO:0003281 ⚠ ABNORMAL atrial septum development GO:0003283 ⚠ ABNORMAL

heart UBERON:0000948

Downstream

Progressive Aortic Root Dilatation

Show evidence (3 references)

PMID:28288113 SUPPORT Human Clinical

"The CHD included atrial/ventricular septal defects and in older individuals aortic root dilation."

Defines the cardiac lesion spectrum in the founding cohort.

PMID:39887622 SUPPORT Human Clinical

"The patient was diagnosed with congenital heart defects, including a ventricular septal defect, atrial septal defect, and patent ductus arteriosus."

Independent case confirming the septal-plus-ductal lesion pattern.

PMID:33075386 PARTIAL In Vitro

"The onset of congenital heart defects associated with this syndrome appears to involve a mechanism caused by UFD1 common to 22q.11.2 deletion syndrome."

Proposes a specific molecular route from kinase hyperactivity to the cardiac defect; hedged by the authors and untested in patient tissue.

Disrupted Skeletal and Connective Tissue Morphogenesis

The skeletal arm of the syndrome affects the digits most consistently, then the axial skeleton and thoracic cage: camptodactyly and finger contractures, fifth-finger clinodactyly, 2-3 toe syndactyly, hindfoot deformity, scoliosis, and pectus excavatum. A connective-tissue dimension runs in parallel - thin skin, joint hypermobility, arachnodactyly, high-arched palate, and spontaneous pneumothorax - which is why these patients are routinely referred to connective-tissue clinics before the molecular diagnosis is made. Notably, the canonical connective-tissue mechanism of increased TGF-beta signalling was tested and NOT found: SMAD2 and SMAD3 phosphorylation were unchanged in the mutant constructs, so CHDSKM does not conform to the TGF-beta-dysregulation aortopathy pattern of Marfan and Loeys-Dietz syndromes despite the clinical resemblance. That negative is the reason this entry declares no conforms_to link to the aortopathy_tgfbeta_dysregulation module.

skeletal system morphogenesis GO:0048705 ⚠ ABNORMAL

Downstream

Progressive Aortic Root Dilatation

Show evidence (3 references)

PMID:28288113 SUPPORT Human Clinical

"Common skeletal abnormalities included pectus excavatum, scoliosis, and finger/toe deformities, in particular hindfoot deformity, and finger contractures"

Defines the skeletal lesion spectrum.

PMID:33223528 SUPPORT Human Clinical

"Phenotypes such as skeletal malformations, aortic root dilatation and pneumothorax point towards an overlap with genetic connective tissue disorders"

Documents the connective-tissue dimension of the skeletal phenotype.

PMID:28288113 REFUTE In Vitro

"we did not observe significant alteration in the phosphorylation level of SMAD2 and SMAD3"

Directly tests and refutes increased TGF-beta signalling as the connective-tissue mechanism, which is why this entry does NOT declare conformance to the aortopathy_tgfbeta_dysregulation module.

Progressive Aortic Root Dilatation

Aortic root enlargement is reported chiefly in older children and adults, consistent with a progressive rather than a static congenital lesion, and at least one patient has had severe and rapidly progressive dilatation. The true risk of aneurysm and dissection is not known: as of the 2021 pooled 18-case review the authors reported no awareness of any affected individual having required surgical intervention for rapid progressive dilatation, which they suggested may indicate a more indolent course than Marfan syndrome - though a 2023 case has since described exactly that pattern, so the indolent-course reading should be treated as provisional. The uncertainty itself is the clinically actionable point: published expert recommendation is baseline and serial aortic root measurement modelled on Marfan surveillance until natural-history data exist.

aortic root UBERON:0001496

Show evidence (2 references)

PMID:36949638 SUPPORT Human Clinical

"he had several features not previously documented, including severe and rapidly progressive aortic root dilatation"

Documents that aortic root dilatation can be severe and rapidly progressive.

PMID:33223528 PARTIAL Human Clinical

"Evidence is currently lacking as to the true risk of aortic aneurysm and dissection in this condition. We are not aware of any affected individuals having had rapid progressive aortic dilatation requiring surgical intervention and this may therefore suggest a more indolent course."

Qualifies the aortic risk claim - the lesion is real but its natural history is undefined and may be more indolent than in Marfan syndrome.

Impaired Prenatal and Postnatal Growth

Growth impairment begins prenatally as intrauterine growth restriction and continues postnatally as failure to thrive with feeding difficulty. In the pooled series failure to thrive is tied with congenital heart disease as the third most frequent feature, behind facial dysmorphism and digital anomalies. Adult stature is variable and does not track the infantile growth failure - most adults are short but tall stature has been reported, so short stature is not a reliable diagnostic handle.

Show evidence (2 references)

PMID:28288113 SUPPORT Human Clinical

"Most individuals had failure to thrive during infancy and early childhood"

Establishes postnatal growth failure as a core feature.

PMID:33223528 SUPPORT Human Clinical

"failure to thrive (14/18), developmental delay (11/18), IUGR (10/18)"

Quantifies both the prenatal and postnatal growth components in the pooled series.

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Pathograph

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Phenotypes

32

Cardiovascular 5

Congenital Heart Defect FREQUENT Abnormal heart morphology HP:0001627

Onset: CONGENITAL

Show evidence (2 references)

PMID:33223528 SUPPORT Human Clinical

"congenital heart disease (14/18), failure to thrive (14/18)"

Congenital heart disease in 14/18 pooled cases (78%) maps to the FREQUENT band (30-79%).

PMID:28288113 SUPPORT Human Clinical

"congenital heart disease (CHD, 6/6), skeletal abnormalities (6/6)"

Congenital heart disease in all six patients of the founding cohort.

Atrial Septal Defect Atrial septal defect HP:0001631

Onset: CONGENITAL

Show evidence (1 reference)

PMID:39887622 SUPPORT Human Clinical

"congenital heart defects, including a ventricular septal defect, atrial septal defect, and patent ductus arteriosus"

Documents atrial septal defect in a molecularly confirmed patient.

Ventricular Septal Defect Ventricular septal defect HP:0001629

Onset: CONGENITAL

Show evidence (1 reference)

PMID:33075386 SUPPORT Human Clinical

"we found a novel ABL1 mutation in a Japanese family with ventricular septal defect, finger contracture, skin abnormalities and failure to thrive"

Ventricular septal defect cosegregating with an ABL1 allele in a multiplex family.

Patent Ductus Arteriosus Patent ductus arteriosus HP:0001643

Onset: CONGENITAL

Show evidence (1 reference)

PMID:39887622 SUPPORT Human Clinical

"congenital heart defects, including a ventricular septal defect, atrial septal defect, and patent ductus arteriosus"

Documents patent ductus arteriosus in a molecularly confirmed patient.

Aortic Root Dilatation Aortic root aneurysm HP:0002616

Course: PROGRESSIVE

Show evidence (2 references)

PMID:28288113 SUPPORT Human Clinical

"The CHD included atrial/ventricular septal defects and in older individuals aortic root dilation."

Establishes aortic root dilatation as an age-dependent cardiovascular feature.

PMID:36949638 SUPPORT Human Clinical

"severe and rapidly progressive aortic root dilatation"

Supports the PROGRESSIVE clinical course qualifier.

Ear 1

Hearing Impairment Hearing impairment HP:0000365

Show evidence (3 references)

PMID:33223528 SUPPORT Human Clinical

"All the affected individuals in this series recapitulate the phenotype of the ABL1 developmental syndrome and additionally we affirm that hearing impairment is a common feature of the condition."

Establishes hearing impairment as a recognised feature of the syndrome.

PMID:33223528 SUPPORT Human Clinical

"four of our cohort exhibit conductive or mixed conductive/sensorineural hearing impairment, which was severe and persistent in one patient"

Specifies the conductive/mixed character of the hearing loss.

PMID:32643838 SUPPORT Human Clinical

"thereby expanding the phenotypic spectrum of CHDSKM to include hearing impairment, lipodystrophy-like features, renal hypoplasia, and distinct ocular abnormalities."

Independent series adding hearing impairment to the CHDSKM spectrum.

Genitourinary 1

Hypospadias Hypospadias HP:0000047

Show evidence (1 reference)

PMID:28288113 SUPPORT Human Clinical

"Hypospadias/hypogonadism was reported in three of four male patients."

Documents male genital anomalies in three of four males.

Head and Neck 3

Characteristic Facial Dysmorphism VERY_FREQUENT Abnormal facial shape HP:0001999

Onset: CONGENITAL

Show evidence (2 references)

PMID:33223528 SUPPORT Human Clinical

"The most common clinical features across all described individuals with ABL1 variants are dysmorphic facies (18/18), finger/toe abnormalities (17/18), congenital heart disease (14/18), failure to thrive (14/18), developmental delay (11/18), IUGR (10/18), ear abnormalities (9/18), palatal..."

Dysmorphic facies in 18/18 pooled cases (100%) supports the VERY_FREQUENT band.

PMID:28288113 SUPPORT Human Clinical

"In younger children, dysmorphic features included a broad forehead, small nose, deep-set eyes, and small chin. In older individuals, the face appeared elongated, with a narrow maxilla, long and narrow nose, and pointed chin"

Describes the age-dependent facial gestalt.

Micrognathia Micrognathia HP:0000347

Show evidence (1 reference)

PMID:39887622 SUPPORT Human Clinical

"distinct facial dysmorphisms such as a broad forehead, frontal bossing, micrognathia, low-set ears, and short palpebral fissures"

Micrognathia listed among hallmark facial features.

Microcephaly FREQUENT Microcephaly HP:0000252

Show evidence (2 references)

PMID:33223528 SUPPORT Human Clinical

"This case series of six new patients with germline heterozygous ABL1 missense variants further delineates the phenotypic spectrum of this condition and recognises microcephaly as a common finding."

Establishes microcephaly as a recognised common feature of the syndrome.

PMID:33223528 SUPPORT Human Clinical

"palatal deformity (9/18) and microcephaly (9/18)"

Microcephaly in 9/18 pooled cases (50%) maps to the FREQUENT band.

Integument 1

Thin Skin Thin skin HP:0000963

Show evidence (1 reference)

PMID:33223528 SUPPORT Human Clinical

"SkinThin skinYesYesYes"

Thin skin recorded as present in three patients in the clinical-features table of the expanded case series; the quoted string is the table row label plus its patient values as they appear in the cached full text.

Limbs 2

Arachnodactyly Arachnodactyly HP:0001166

Show evidence (1 reference)

PMID:33223528 SUPPORT Human Clinical

"Camptodactyly of fingers, arachnodactyly"

Arachnodactyly recorded in the finger/toe abnormality row of the case series clinical-features table.

Toe Syndactyly Toe syndactyly HP:0001770

Show evidence (1 reference)

PMID:33223528 SUPPORT Human Clinical

"2–3 toe syndactyly, camptodactyly of fingers, clinodactyly of 5th fingers"

Documents toe syndactyly among digital anomalies in the case series.

Musculoskeletal 5

Camptodactyly Camptodactyly HP:0012385

Show evidence (1 reference)

PMID:33223528 SUPPORT Human Clinical

"Some other phenotypic features are also over-represented in our cohort, including camptodactyly (5/6) and microcephaly (5/6)."

Camptodactyly in 5 of 6 patients of the expanded case series.

Lipodystrophy-Like Features Lipodystrophy HP:0009125

Show evidence (1 reference)

PMID:32643838 PARTIAL Human Clinical

"thereby expanding the phenotypic spectrum of CHDSKM to include hearing impairment, lipodystrophy-like features, renal hypoplasia, and distinct ocular abnormalities."

The source says "lipodystrophy-like", not frank lipodystrophy, so the HP term is an approximation and the evidence is PARTIAL.

Scoliosis Scoliosis HP:0002650

Show evidence (2 references)

PMID:28288113 SUPPORT Human Clinical

"Common skeletal abnormalities included pectus excavatum, scoliosis, and finger/toe deformities"

Scoliosis among the common skeletal abnormalities of the founding cohort.

PMID:39887622 SUPPORT Human Clinical

"Skeletal malformations included scoliosis and finger contractures."

Independent confirmation in a molecularly confirmed patient.

Pectus Excavatum Pectus excavatum HP:0000767

Show evidence (1 reference)

PMID:28288113 SUPPORT Human Clinical

"Common skeletal abnormalities included pectus excavatum, scoliosis"

Pectus excavatum among the common skeletal abnormalities.

Joint Hypermobility Joint hypermobility HP:0001382

Show evidence (2 references)

PMID:28288113 SUPPORT Human Clinical

"Three patients had joint hyper-extensibility/laxity."

Joint laxity in 3 of 6 patients of the founding cohort.

PMID:41416177 SUPPORT Human Clinical

"he revealed a history of skeletal malformations in the hands and joint hypermobility"

Independent adult case with joint hypermobility.

Nervous System 1

Developmental Delay FREQUENT Global developmental delay HP:0001263

Show evidence (1 reference)

PMID:33223528 SUPPORT Human Clinical

"failure to thrive (14/18), developmental delay (11/18), IUGR (10/18)"

Developmental delay in 11/18 pooled cases (61%) maps to the FREQUENT band (30-79%).

Growth 3

Failure to Thrive FREQUENT Failure to thrive HP:0001508

Onset: INFANTILE

Show evidence (1 reference)

PMID:33223528 SUPPORT Human Clinical

"congenital heart disease (14/18), failure to thrive (14/18), developmental delay (11/18)"

Failure to thrive in 14/18 pooled cases (78%) maps to the FREQUENT band (30-79%).

Intrauterine Growth Restriction FREQUENT Intrauterine growth retardation HP:0001511

Onset: ANTENATAL

Show evidence (1 reference)

PMID:33223528 SUPPORT Human Clinical

"developmental delay (11/18), IUGR (10/18), ear abnormalities (9/18)"

IUGR in 10/18 pooled cases (56%) maps to the FREQUENT band (30-79%).

Short Stature Short stature HP:0004322

Show evidence (1 reference)

PMID:33223528 PARTIAL Human Clinical

"Interestingly, two individuals have tall stature, in contrast to short stature in the majority of cases."

Supports short stature as the majority outcome while explicitly documenting the tall-stature exception; hence PARTIAL.

Other 10

Palatal Abnormality FREQUENT Abnormal palate morphology HP:0000174

Show evidence (1 reference)

PMID:33223528 SUPPORT Human Clinical

"ear abnormalities (9/18), palatal deformity (9/18) and microcephaly (9/18)"

Palatal deformity in 9/18 pooled cases (50%) maps to the FREQUENT band (30-79%).

Ear Malformation FREQUENT Abnormal ear morphology HP:0031703

Show evidence (1 reference)

PMID:33223528 SUPPORT Human Clinical

"ear abnormalities (9/18), palatal deformity (9/18) and microcephaly (9/18)"

Ear abnormalities in 9/18 pooled cases (50%) maps to the FREQUENT band.

Pulmonic Stenosis Supravalvar pulmonary stenosis HP:0034349

Show evidence (1 reference)

PMID:33223528 SUPPORT Human Clinical

"Supra-valvular pulmonary stenosis"

Reported cardiac finding in the expanded ABL1 case series.

Finger and Toe Malformations VERY_FREQUENT Abnormal digit morphology HP:0011297

Show evidence (2 references)

PMID:33223528 SUPPORT Human Clinical

"dysmorphic facies (18/18), finger/toe abnormalities (17/18)"

Finger/toe abnormalities in 17/18 pooled cases (94%) supports the VERY_FREQUENT band.

PMID:33223528 SUPPORT Human Clinical

"Some other phenotypic features are also over-represented in our cohort, including camptodactyly (5/6) and microcephaly (5/6)."

Camptodactyly, the commonest single digital anomaly, documented in 5 of 6 patients of the expanded cohort. Note the pooled 17/18 denominator above is for digital anomalies as a class, not for camptodactyly specifically, which is why the frequency band sits on the class-level term.

Ocular Abnormalities Abnormality of the eye HP:0000478

Show evidence (2 references)

PMID:32643838 SUPPORT Human Clinical

"thereby expanding the phenotypic spectrum of CHDSKM to include hearing impairment, lipodystrophy-like features, renal hypoplasia, and distinct ocular abnormalities."

Adds distinct ocular abnormalities to the documented CHDSKM spectrum.

PMID:33223528 SUPPORT Human Clinical

"Almond-shaped eyes, epiblepharon"

Specific ocular findings recorded in the eyes row of the case-series clinical-features table.

Finger Contracture Finger joint contracture HP:0034681

Show evidence (1 reference)

PMID:28288113 SUPPORT Human Clinical

"Common skeletal abnormalities included pectus excavatum, scoliosis, and finger/toe deformities, in particular hindfoot deformity, and finger contractures"

Finger contractures listed among the common skeletal abnormalities.

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

Show evidence (1 reference)

PMID:33223528 SUPPORT Human Clinical

"Camptodactyly, clinodactyly of 5th finger, slender fingers"

Fifth-finger clinodactyly documented in the expanded case series.

Renal Hypoplasia Renal hypoplasia HP:0000089

Show evidence (1 reference)

PMID:32643838 SUPPORT Human Clinical

"expanding the phenotypic spectrum of CHDSKM to include hearing impairment, lipodystrophy-like features, renal hypoplasia, and distinct ocular abnormalities."

Adds renal hypoplasia to the documented CHDSKM phenotype spectrum.

Gastrointestinal Dysmotility and Reflux Gastrointestinal dysmotility HP:0002579

Show evidence (2 references)

PMID:36949638 SUPPORT Human Clinical

"gastro-intestinal reflux secondary to esophageal dysmotility with gastric strictures"

Documents oesophageal dysmotility as the basis of reflux in a CHDSKM patient.

PMID:28288113 SUPPORT Human Clinical

"gastrointestinal problems (5/6)"

Gastrointestinal involvement in five of six patients of the founding cohort.

Spontaneous Pneumothorax Spontaneous pneumothorax HP:0002108

Show evidence (2 references)

PMID:41416177 SUPPORT Human Clinical

"We present the clinical case of a 20-year-old male patient who presented recurrent pneumothorax on 5 occasions"

Recurrent pneumothorax as the presenting feature of a molecularly confirmed CHDSKM patient.

PMID:33223528 SUPPORT Human Clinical

"Phenotypes such as skeletal malformations, aortic root dilatation and pneumothorax point towards an overlap with genetic connective tissue disorders"

Places pneumothorax within the connective-tissue overlap of the syndrome.

🧬

Genetic Associations

1

ABL1 Gain-of-Function Missense Variants (CAUSAL)

Gene: ABL1 hgnc:76 relationship_type: CAUSATIVE

Show evidence (4 references)

PMID:28288113 SUPPORT Human Clinical

"The variant c.734A>G (p.Tyr245Cys) was found to occur de novo or cosegregate with disease in five individuals (families 1-3)."

Identifies the recurrent founding ABL1 allele for CHDSKM.

PMID:33223528 SUPPORT Human Clinical

"Here, we describe a series of six new unrelated individuals with heterozygous missense variants in ABL1 (including four novel variants) identified via whole exome sequencing."

Expands the allelic series with four additional novel missense variants.

PMID:32643838 SUPPORT Human Clinical

"we describe three de novo missense variants, c.407C>T (p.Thr136Met), c.746C>T (p.Pro249Leu), and c.1573G>A (p.Val525Met), and one recurrent variant, c.1066G>A (p.Ala356Thr), in six patients"

Further extends the pathogenic ABL1 missense allele spectrum.

+ 1 more reference

💊

Medical Actions

11

Surgical or Catheter Repair of Congenital Heart Defects

Category: Therapeutic Action: cardiac surgical procedure Ontology label: Cardiac Surgery NCIT:C157806

Defect-specific management of septal defects, patent ductus arteriosus, and outflow tract lesions by paediatric or adult congenital cardiology, following standard congenital heart disease practice. There is no CHDSKM-specific cardiac surgical protocol; the lesions are managed on their own merits.

Target Phenotypes: Atrial septal defect HP:0001631 Ventricular septal defect HP:0001629 Patent ductus arteriosus HP:0001643

Show evidence (1 reference)

PMID:28288113 PARTIAL Human Clinical

"The CHD included atrial/ventricular septal defects and in older individuals aortic root dilation."

Establishes the repairable lesion set that this treatment addresses. No CHDSKM-specific surgical series or outcome data exist, so this is indication evidence only and supports no efficacy claim; the lesions are managed under general congenital heart disease practice.

Aortic Root Surveillance by Serial Echocardiography

Category: Monitoring Action: echocardiography Ontology label: Echocardiography Test NCIT:C16525

Baseline measurement of the aortic root diameter at diagnosis and ongoing serial imaging, explicitly modelled on Marfan syndrome surveillance. The expert recommendation is explicitly precautionary: the true risk of aneurysm and dissection in CHDSKM is unknown, and as of the 2021 pooled series no patient had been reported to require surgical intervention for rapid progressive dilatation. A 2023 case has since documented severe and rapidly progressive dilatation, which strengthens rather than weakens the case for surveillance; the recommendation stands until natural-history data become available.

Show evidence (3 references)

PMID:33223528 SUPPORT Human Clinical

"Furthermore, assessment of the aortic root diameter at the time of diagnosis may also be appropriate in individuals found to have pathogenic ABL1 variants."

Direct expert recommendation for baseline aortic root assessment.

PMID:33223528 SUPPORT Human Clinical

"a precautionary approach of ongoing aortic root screening similar to that used for Marfan syndrome may be appropriate until such time as more accurate natural history data are available"

States the Marfan-modelled, explicitly precautionary basis for serial surveillance.

PMID:36949638 SUPPORT Human Clinical

"lend strength to previous calls for close surveillance of the aortic root from a young age in CHDSKM"

Independent case reinforcing early and close aortic root surveillance.

Audiological Assessment and Hearing Rehabilitation

Category: Screening

Formal audiology at diagnosis and thereafter, with hearing aids or ENT intervention as indicated. The rationale is the high frequency of conductive and mixed hearing impairment in the syndrome, which was under-recognised in the original description. No NCIT clinical-action term for audiological assessment is reachable from NCIT:C25218, so this treatment carries a free-text preferred_term only.

Show evidence (1 reference)

PMID:33223528 SUPPORT Human Clinical

"The high prevalence of hearing impairment makes audiological assessment advisable."

Direct expert recommendation for audiological assessment in CHDSKM.

Nutritional Support for Failure to Thrive

Category: Therapeutic Action: nutritional support Ontology label: Nutritional Support NCIT:C15433

Nutritional and feeding management during infancy and early childhood, addressing the feeding difficulties and growth failure that affect most patients. Supportive rather than disease-modifying.

Target Phenotypes: Failure to thrive HP:0001508

Show evidence (1 reference)

PMID:28288113 PARTIAL Human Clinical

"Most individuals had failure to thrive during infancy and early childhood"

Establishes the clinical need being addressed; no CHDSKM-specific nutritional intervention study exists, so this is indication evidence only.

Orthopaedic Management of Scoliosis and Contractures

Category: Therapeutic Action: orthopedic surgical procedure Ontology label: Orthopedic Surgical Procedure NCIT:C16186

Spinal surveillance with bracing or surgical correction for progressive scoliosis, and physiotherapy, occupational therapy, or surgery for finger contractures, camptodactyly, and foot deformity. At least one reported patient required surgical intervention for scoliosis.

Target Phenotypes: Scoliosis HP:0002650 Finger joint contracture HP:0034681

Show evidence (1 reference)

PMID:33223528 PARTIAL Human Clinical

"ScoliosisYes (surgical intervention)"

Table entry recording surgical intervention for scoliosis in a CHDSKM patient; establishes the practice, not an efficacy claim.

Developmental and Rehabilitative Therapy

Category: Therapeutic Action: physical therapy Ontology label: Physical Therapy NCIT:C15302

Physical, occupational, and speech and language therapy with developmental paediatric follow-up, indicated by the developmental delay present in a majority of reported patients and by the hand-function consequences of camptodactyly and finger contractures. Supportive; there is no CHDSKM-specific rehabilitation protocol or outcome study.

Target Phenotypes: Global developmental delay HP:0001263

Show evidence (1 reference)

PMID:33223528 PARTIAL Human Clinical

"failure to thrive (14/18), developmental delay (11/18), IUGR (10/18)"

Establishes the developmental-delay burden that this supportive care addresses; indication evidence only, with no efficacy claim.

ABL-Directed Tyrosine Kinase Inhibition (Investigational)

Category: Therapeutic Action: Pharmacotherapy NCIT:C15986

Agent: imatinib CHEBI:45783

NOT an established treatment. Imatinib abolishes the excess phosphorylation of mutant ABL1 constructs in vitro, which makes the gain-of-function mechanism pharmacologically tractable in principle and is the sole basis for interest in ABL-directed tyrosine kinase inhibitors here. The authors of that work do advance a therapeutic hypothesis: because the germline alleles functionally mimic the loss of the ABL1 N-terminus in BCR-ABL, they expect TKIs effective against BCR-ABL to be similarly effective against the variant proteins, and they raise limiting aortic root dilatation as a candidate indication. Three considerations nevertheless weigh against clinical use outside a rigorously justified research protocol. First, the malformations arise during embryofetal development, so any meaningful effect would require treatment from a very early age and lifelong exposure. Second, imatinib is expected to be teratogenic in pregnancy, and severe congenital malformations have been reported in fetuses exposed to it - though the original authors caution that no definitive conclusion about imatinib teratogenicity can be drawn from the small number of cases, several of which also involved exposure to other teratogens such as warfarin or hydroxyurea. Third, structural work shows that type II ATP-site inhibitors such as imatinib promote disassembly of the very regulatory core whose disassembly drives the disease, whereas the allosteric myristoyl-pocket inhibitor asciminib stabilises the alpha-I helix instead - so the two inhibitor classes are not interchangeable and leukaemia dosing cannot simply be transplanted into a developmental syndrome.

Mechanism Target:

INHIBITS Constitutive ABL1 Tyrosine Kinase Hyperactivity

Show evidence (5 references)

PMID:33223528 PARTIAL In Vitro

"Finally, as expected, imatinib abolished phosphorylation of ABL1-Tyr245 and STAT5B in all of the constructs"

In vitro pharmacological tractability only; no clinical evidence of benefit in CHDSKM, hence PARTIAL.

PMID:33223528 PARTIAL Other

"While imatinib is used to treat paediatric CML cases, it is expected to be teratogenic in pregnancy. Further work is therefore required to ascertain whether therapeutic scope exists for use of imatinib or similar TKIs in this condition."

The authors' own caveat, stated as expert discussion rather than as a reported observation: teratogenicity risk and absence of evidence for therapeutic scope in this condition.

PMID:33223528 PARTIAL Other

"TKIs may potentially in some way be therapeutically beneficial for the ABL1 developmental syndrome or its complications, for example in limiting aortic root dilatation or reducing the tendency for dilatation to occur."

The therapeutic hypothesis the same authors advance, recorded alongside their cautions so the entry reflects both halves of the source argument.

+ 2 more references

Malignancy Screening

Category: Screening Action: cancer screening Ontology label: Cancer Screening NCIT:C15406

Systematic clinical screening for ABL1-associated cancers, recommended by the authors of the original description on the precautionary grounds that the germline alleles increase the activity of a proto-oncogene. This is a prudential recommendation, not an evidence-based protocol: no malignancy has been reported in any CHDSKM patient, no screening modality or interval has been specified or validated, and the lifetime risk is unquantified. The corresponding evidence gap is tracked in the chdskm_malignancy_risk discussion.

Show evidence (1 reference)

PMID:28288113 PARTIAL Human Clinical

"Malignancies have not been detected in any of the affected individuals with ABL1 germline variants, but as they cause increased phosphorylation and possibly increased kinase activity of this proto-oncogene, it may be prudent to perform systematic clinical screening for ABL1-associated cancers in..."

The recommendation and its explicitly prudential, unvalidated basis, both stated in the same sentence; PARTIAL because no risk estimate, modality, or interval is given.

Baseline Renal Imaging

Category: Screening Action: renal ultrasound Ontology label: Renal Ultrasound NCIT:C159885

Renal ultrasound at diagnosis, indicated by the renal hypoplasia added to the CHDSKM spectrum by the expanded series and by the unilateral renal agenesis recorded in the case-series table. Detection-oriented; no CHDSKM-specific screening interval has been defined.

Show evidence (1 reference)

PMID:32643838 SUPPORT Human Clinical

"expanding the phenotypic spectrum of CHDSKM to include hearing impairment, lipodystrophy-like features, renal hypoplasia, and distinct ocular abnormalities."

Renal hypoplasia in the documented spectrum is the indication for baseline renal imaging.

Baseline Ophthalmologic Evaluation

Category: Screening Action: eye examination Ontology label: Eye Examination NCIT:C38060

Eye examination at diagnosis, indicated by the distinct ocular abnormalities added to the CHDSKM spectrum by the expanded series. The source does not enumerate the findings in its abstract, so this is a detection-oriented baseline rather than a search for a specified lesion.

Show evidence (1 reference)

PMID:32643838 SUPPORT Human Clinical

"expanding the phenotypic spectrum of CHDSKM to include hearing impairment, lipodystrophy-like features, renal hypoplasia, and distinct ocular abnormalities."

Distinct ocular abnormalities in the documented spectrum are the indication for baseline eye examination.

Genetic Counseling and Cascade Testing

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

Counseling for the recurrence risk from an affected heterozygous parent, with cascade testing of at-risk relatives once a familial variant is identified. Because the condition is autosomal dominant, each pregnancy of an affected heterozygous parent carries a one-in-two transmission risk; the documented father-to-child and mother-to-child transmissions of p.Tyr245Cys make this a real rather than theoretical counseling scenario. Counseling must convey that expressivity is variable, so severity in an affected child cannot be predicted from the parent's phenotype, and that most probands to date have carried de novo variants. Once a familial variant is known, prenatal diagnosis and preimplantation genetic testing for monogenic disease are technically available reproductive options.

Show evidence (1 reference)

PMID:28288113 SUPPORT Human Clinical

"In family 3, p.Tyr245Cys was found to be inherited from the similarly affected father."

Documented parent-to-child transmission establishes the recurrence risk that genetic counseling addresses.

🔀

Differential Diagnoses

4

Conditions with similar clinical presentations that must be differentiated from Congenital Heart Defects and Skeletal Malformations Syndrome:

Marfan Syndrome MONDO:0007947

Overlapping Features The marfanoid habitus, arachnodactyly, joint laxity, high-arched palate, aortic root dilatation, and spontaneous pneumothorax of CHDSKM overlap Marfan syndrome closely enough that Marfan was the working differential diagnosis in one of the four founding families, and CHDSKM patients are still reached through connective-tissue gene panels.

Distinguishing Features

CHDSKM adds congenital septal heart defects, digital contractures and camptodactyly, intrauterine growth restriction and failure to thrive, microcephaly, and hearing impairment, none of which are Marfan features.
Ectopia lentis, a cardinal Marfan diagnostic feature, has not been reported in any published CHDSKM patient, although "distinct ocular abnormalities" of unspecified type are part of the CHDSKM spectrum, so this discriminator should be applied with care.
The TGF-beta dysregulation that characterises FBN1-related aortopathy was tested in CHDSKM and not found (SMAD2/SMAD3 phosphorylation unchanged).
Causal gene ABL1 rather than FBN1.

Show evidence (1 reference)

PMID:28288113 SUPPORT Human Clinical

"Due to cardiac and skeletal manifestations, differential diagnoses commonly included connective tissue disorders, e.g. Marfan syndrome in families 3."

Marfan syndrome was the clinical differential in a founding CHDSKM family.

Loeys-Dietz Syndrome MONDO:0018954

Overlapping Features Loeys-Dietz syndrome shares the long face, high-arched palate, microretrognathia, pectus deformity, scoliosis, arachnodactyly, joint laxity, and aortic root aneurysm, and was named alongside Shprintzen-Goldberg syndrome as a formal differential in the original CHDSKM report.

Distinguishing Features

Loeys-Dietz is caused by TGFBR1, TGFBR2, SMAD3, TGFB2, or TGFB3 variants with demonstrably dysregulated TGF-beta signalling; CHDSKM shows no SMAD2/SMAD3 phosphorylation change.
Loeys-Dietz carries a high risk of aggressive aortic dissection requiring early prophylactic surgery; the CHDSKM aortic natural history is undefined and may be more indolent.
Arterial tortuosity, hypertelorism, and bifid uvula are characteristic of Loeys-Dietz and have not been reported in published CHDSKM patients.
CHDSKM adds septal defects, digital contractures, growth failure, and hearing loss.

Show evidence (1 reference)

PMID:28288113 SUPPORT Human Clinical

"The differential diagnosis of the newly described syndrome includes Shprintzen-Goldberg syndrome (dolichostenomelia, arachnodactyly, pectus deformity, scoliosis, aortic root enlargement, and high-arched palate) and Loeys-Dietz syndrome"

Loeys-Dietz named as a formal differential in the original report.

Van den Ende-Gupta Syndrome Not Yet Curated MONDO:0010959

Overlapping Features Van den Ende-Gupta syndrome (VDEGS) is the differential that most often causes genuine molecular misclassification rather than merely clinical confusion: three individuals with classical VDEGS features and negative SCARF2 testing were subsequently found to carry pathogenic ABL1 variants, and their phenotype was reclassified as CHDSKM.

Distinguishing Features

VDEGS is autosomal recessive and caused by biallelic SCARF2 variants; CHDSKM is autosomal dominant and caused by heterozygous ABL1 gain-of-function missense alleles.
The shared clinical handles are arachnodactyly and blepharophimosis with distinctive facial and skeletal features.
Because the two overlap, individuals with arachnodactyly plus blepharophimosis should have echocardiography and testing of both SCARF2 and ABL1.

Show evidence (2 references)

PMID:33783941 SUPPORT Human Clinical

"Three were found to have pathogenic ABL1 variants using whole exome sequencing (WES) or whole genome sequencing (WGS). Their phenotype was consistent with the congenital heart disease and skeletal malformations syndrome (CHDSKM), which has been associated with ABL1 variants."

Documents actual reclassification of VDEGS-phenotype patients as CHDSKM.

PMID:33783941 SUPPORT Human Clinical

"individuals with the combination of arachnodactyly and blepharophimosis should undergo echocardiography while awaiting results of molecular testing due to the overlapping physical features of VDEGS and CHDSKM."

States the practical diagnostic consequence of the VDEGS-CHDSKM overlap.

Human ABL1 Deficiency Syndrome

Overlapping Features The allelic counterpart of CHDSKM at the same locus. Biallelic loss-of-function ABL1 variants cause a distinct recognisable syndrome of multiple congenital malformations and facial dysmorphism that is described as opposite to CHDSKM in many respects - the clearest possible demonstration that ABL1 activity must be held within a narrow band during development, and the reason the two must never be merged into one entity.

Distinguishing Features

ABL1 deficiency syndrome is autosomal recessive, arises in consanguineous families, and is caused by homozygous loss-of-function alleles.
CHDSKM is autosomal dominant and caused by heterozygous gain-of-function missense alleles.
The dysmorphic gestalts are reported as opposite in many features.
Molecular reports must therefore state zygosity and predicted functional direction, not merely that an ABL1 variant is present.

Show evidence (1 reference)

PMID:38743093 SUPPORT Human Clinical

"The associated phenotype is multiple congenital malformations and distinctive facial dysmorphism that are opposite in many ways to CHDSKM. We suggest that a tight balance of ABL1 activity is required during embryonic development and that both germline gain of function and loss of function..."

Establishes ABL1 deficiency syndrome as a distinct allelic disorder, not a CHDSKM variant.

{ }

Source YAML

click to show

name: Congenital Heart Defects and Skeletal Malformations Syndrome
creation_date: "2026-08-01T00:00:00Z"
category: Mendelian
description: >
  Congenital heart defects and skeletal malformations syndrome (CHDSKM;
  OMIM 617602) is an ultra-rare autosomal dominant multisystem developmental
  disorder caused by heterozygous germline gain-of-function missense variants
  in ABL1, the non-receptor tyrosine kinase best known as the 3' partner of the
  somatic BCR::ABL1 fusion of chronic myeloid leukaemia. The best-characterised
  pathogenic alleles fall in autoinhibitory regulatory elements of the protein -
  the myristoyl-binding pocket of the kinase domain, the SH2-kinase linker, and
  the C-terminal alpha-I helix - so that the assembled, low-activity
  SH3-SH2-kinase regulatory core is destabilised and kinase activity rises;
  several later-reported alleles have not been mapped to any defined regulatory
  element, so the clustering is a property of the well-studied alleles rather
  than of the whole allelic series. The resulting
  clinical picture combines congenital heart disease (atrial and ventricular
  septal defects, patent ductus arteriosus, pulmonic stenosis, and aortic root
  dilatation), skeletal and digital malformations (camptodactyly, finger
  contractures, scoliosis, pectus excavatum, hindfoot deformity), a
  characteristic narrow face with small pointed chin, prenatal and postnatal
  growth failure, hearing impairment, and variable developmental delay and
  microcephaly. Because the marfanoid habitus, joint laxity, aortic root
  dilatation, and spontaneous pneumothorax overlap heritable connective-tissue
  disease, CHDSKM is frequently first considered as Marfan, Loeys-Dietz, or
  Shprintzen-Goldberg syndrome; the entity is defined molecularly rather than
  by the descriptive cardiac-plus-skeletal label it carries.
synonyms:
- CHDSKM
- ABL1-related congenital heart defects and skeletal malformations syndrome
- ABL1 malformation syndrome
- marfanoid habitus-facial dysmorphism-skeletal abnormality-heart defect syndrome
disease_term:
  preferred_term: congenital heart defects and skeletal malformations syndrome
  term:
    id: MONDO:0060532
    label: congenital heart defects and skeletal malformations syndrome
notes: >
  Identity anchors used for the Named Entity Confusion (NEC) preflight before
  any deep-research content was accepted: MONDO:0060532, OMIM:617602,
  Orphanet:643503, and the MONDO structured gene relationship
  RO:0004003 hgnc:76 (ABL1). The descriptive label "congenital heart defects
  and skeletal malformations" is shared, as a phenotype pair, with several
  well-known but mechanistically unrelated syndromes (Holt-Oram/TBX5,
  Ellis-van Creveld/EVC-EVC2, Char syndrome/TFAP2B, VACTERL association);
  none of those are in scope here. Two allelic distinctions also matter and
  are deliberately kept as separate entities: the somatic BCR::ABL1 fusion
  neoplasms (chronic myeloid leukaemia, Ph-positive ALL), and human ABL1
  deficiency syndrome (HADS), which is caused by biallelic loss-of-function
  ABL1 alleles and is phenotypically the opposite of CHDSKM in many respects.
  No GeneReviews chapter exists for ABL1 or CHDSKM (PubMed searches for
  "ABL1 GeneReviews" and "congenital heart defects and skeletal malformations
  GeneReviews" returned no matching chapter), so the mandatory GeneReviews
  phenotype baseline does not apply; the phenotype baseline used instead is
  the pooled 18-case series tabulated by Blakes et al. (PMID:33223528).
  Orphanet epidemiology was not quoted because the local Orphadata refresh is
  currently failing a manifest checksum; the prevalence record therefore uses a
  qualitative band with a literature case count.
classifications:
  harrisons_chapter:
  - classification_value: GENETICS_ENVIRONMENT_DISEASE
    notes: >
      Mendelian, autosomal dominant single-gene developmental disorder; the
      primary clinical home is genetics/dysmorphology rather than any single
      organ system.
    evidence:
    - reference: PMID:32643838
      reference_title: "The expanding clinical phenotype of germline ABL1-associated congenital heart defects and skeletal malformations syndrome."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Congenital heart defects and skeletal malformations syndrome (CHDSKM) is a rare \nautosomal dominant disorder characterized by congenital heart disease, skeletal \nabnormalities, and failure to thrive. CHDSKM is caused by germline mutations in \nABL1."
      explanation: Establishes CHDSKM as a Mendelian autosomal dominant germline single-gene disorder.
  - classification_value: CARDIOVASCULAR
    notes: >
      Congenital heart disease is a cardinal manifestation and, together with
      aortic root dilatation, drives much of the surveillance and management
      burden.
    evidence:
    - reference: PMID:36949638
      reference_title: "ABL1-related congenital heart defects and skeletal malformations syndrome in a patient from Sub-Saharan Africa: A case report highlighting novel cardiac features."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "rare syndrome characterized by distinctive facial features, \ncongenital cardiac lesions, failure to thrive, and skeletal abnormalities."
      explanation: Congenital cardiac lesions are a defining component of the syndrome.
inheritance:
- name: Autosomal Dominant
  inheritance_term:
    preferred_term: Autosomal dominant inheritance
    term:
      id: HP:0000006
      label: Autosomal dominant inheritance
  expressivity: VARIABLE
  description: >
    Heterozygous ABL1 missense alleles act dominantly. Most reported probands
    carry de novo variants, but vertical transmission from an affected parent
    to an affected child has been documented for the recurrent p.Tyr245Cys
    allele, establishing cosegregation rather than de novo occurrence alone.
    Expressivity is variable - stature, for example, ranges from short to tall
    within the same molecular condition - and numerical penetrance cannot be
    estimated from the small published pedigrees.
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Here we report ABL1 \ngermline variants cosegregating with an autosomal dominant disorder \ncharacterized by congenital heart disease, skeletal abnormalities, and failure \nto thrive."
    explanation: Original report establishing autosomal dominant inheritance with cosegregation.
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Sanger sequencing of asymptomatic parents of the probands in families 1 and 2 was negative for p.Tyr245Cys, indicating the variant arose de novo in the probands. Subject 1's similarly affected daughter was found to have inherited the heterozygous p.Tyr245Cys substitution. In family 3, p.Tyr245Cys was found to be inherited from the similarly affected father."
    explanation: Documents both de novo occurrence and parent-to-child transmission of the same allele.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Interestingly, two individuals have tall stature, in contrast to short stature in the majority of cases."
    explanation: Illustrates variable expressivity across carriers of pathogenic ABL1 alleles.
prevalence:
- population: Worldwide
  measure_type: CASES_IN_LITERATURE
  prevalence_class: ULTRA_RARE
  notes: >
    No population prevalence or incidence has ever been measured. The published
    denominator is a pooled case series of 18 individuals reported by 2021,
    with a handful of additional single-patient reports since. This is a case
    count, not a prevalence estimate.
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The most common clinical features across all described individuals with ABL1 variants are dysmorphic facies (18/18), finger/toe abnormalities (17/18), congenital heart disease (14/18), failure to thrive (14/18), developmental delay (11/18), IUGR (10/18), ear abnormalities (9/18), palatal deformity (9/18) and microcephaly (9/18)"
    explanation: >
      The 18-individual denominator for all described cases as of 2021 is the
      basis for the ultra-rare classification and the CASES_IN_LITERATURE
      measure type.
genetic:
- name: ABL1 Gain-of-Function Missense Variants
  gene_term:
    preferred_term: ABL1
    term:
      id: hgnc:76
      label: ABL1
  association: CAUSAL
  relationship_type: CAUSATIVE
  notes: >
    ABL1 (9q34.12) encodes a ubiquitously expressed non-receptor tyrosine
    kinase. CHDSKM alleles are heterozygous germline missense substitutions
    annotated against the isoform 1b transcript NM_007313.2. They are not
    haploinsufficiency alleles: mouse heterozygotes for Abl1 null alleles are
    largely unaffected, and the human alleles increase rather than decrease
    kinase output. Reported disease alleles include p.Val244Ala,
    p.Tyr245Cys, p.Gln300Glu, p.Ala356Thr, p.Ala452Thr, p.Ile508Leu,
    p.Val525Ala, and p.Glu528Lys, plus p.Thr136Met, p.Pro249Leu, p.Val525Met,
    and p.Trp67Arg. The recurrent alleles p.Tyr245Cys and p.Ala356Thr account
    for a disproportionate share of reported patients. Note that only a subset
    of these alleles has been localised to a named regulatory element: the
    myristoyl-pocket cluster (Ala356, Ala452, Val525, Glu528) and the
    SH2-kinase linker (Val244, Tyr245) are mapped, whereas p.Trp67Arg,
    p.Thr136Met, p.Pro249Leu, p.Gln300Glu, and p.Ile508Leu are reported without
    a domain assignment beyond, for p.Ile508Leu, the kinase domain.
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The variant c.734A>G (p.Tyr245Cys) was found to occur de novo or \ncosegregate with disease in five individuals (families 1-3)."
    explanation: Identifies the recurrent founding ABL1 allele for CHDSKM.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Here, we describe a series of \nsix new unrelated individuals with heterozygous missense variants in ABL1 \n(including four novel variants) identified via whole exome sequencing."
    explanation: Expands the allelic series with four additional novel missense variants.
  - reference: PMID:32643838
    reference_title: "The expanding clinical phenotype of germline ABL1-associated congenital heart defects and skeletal malformations syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "we describe three de novo missense variants, c.407C>T (p.Thr136Met), \nc.746C>T (p.Pro249Leu), and c.1573G>A (p.Val525Met), and one recurrent variant, \nc.1066G>A (p.Ala356Thr), in six patients"
    explanation: Further extends the pathogenic ABL1 missense allele spectrum.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Heterozygotes of both strains are largely unaffected, suggesting that ABL1 does not display haploinsufficiency, and supporting the possibility that the human germline missense variants act through a gain of function."
    explanation: >
      Mouse heterozygous null data argue against haploinsufficiency and for a
      gain-of-function disease mechanism in the human syndrome.
variants:
- name: ABL1 p.Tyr245Cys
  description: >
    NM_007313.2:c.734A>G, p.(Tyr245Cys). The founding recurrent CHDSKM allele.
    Tyr245 lies in the SH2-kinase linker, whose docking to the SH3 domain is
    one of the linchpins holding ABL1 in the inactive closed conformation.
    Paradoxically, phosphorylation of Tyr245 is required for maximal wild-type
    kinase activity and the p.Tyr245Phe substitution reduces activity, yet
    p.Tyr245Cys increases overall tyrosine phosphorylation - so the two
    substitutions at the same residue have opposite functional effects.
  gene:
    preferred_term: ABL1
    term:
      id: hgnc:76
      label: ABL1
  type: MISSENSE
  clinical_significance: PATHOGENIC
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "These results support the contention that the p.Tyr245Phe and p.Tyr245Cys substitutions have opposite effects (gain-of-function vs. loss of function) on ABL1 kinase activities."
    explanation: >
      Direct functional comparison establishing p.Tyr245Cys as gain of function
      despite abolishing the activating autophosphorylation site.
- name: ABL1 p.Ala356Thr
  description: >
    NM_007313.2:c.1066G>A, p.(Ala356Thr). The second recurrent CHDSKM allele
    and the prototype of the myristoyl-binding-pocket cluster. Ala356 sits in
    the pocket that binds the N-terminal myristoyl group of isoform 1b, the
    intramolecular interaction that locks the kinase in its autoinhibited
    conformation; substitution by the polar threonine disrupts the hydrophobic
    contacts that hold the myristoyl group in place.
  gene:
    preferred_term: ABL1
    term:
      id: hgnc:76
      label: ABL1
  type: MISSENSE
  clinical_significance: PATHOGENIC
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "The p.Ala356 residue is located in the myristoyl-binding site of the ABL1 kinase domain which intra molecularly binds the N-terminal myristoyl group and forms an autoinhibition conformation."
    explanation: Locates the recurrent Ala356 allele in the autoinhibitory myristoyl-binding pocket.
- name: ABL1 p.Glu528Lys
  description: >
    NM_007313.2:c.1582G>A, p.(Glu528Lys). A de novo CHDSKM allele in the
    C-terminal alpha-I helix. Structural and biophysical work has since shown
    that Glu528 forms a salt bridge with the kinase-domain C-lobe; breaking it
    increases the mechanical force the alpha-I helix exerts on the SH2 domain,
    disassembling the regulatory core and strongly activating the kinase. This
    is the best mechanistically resolved CHDSKM allele.
  gene:
    preferred_term: ABL1
    term:
      id: hgnc:76
      label: ABL1
  type: MISSENSE
  clinical_significance: LIKELY_PATHOGENIC
  evidence:
  - reference: PMID:38588001
    reference_title: "The molecular basis of Abelson kinase regulation by its αI-helix."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "The αI-helix mutation E528K, which is responsible for the ABL1 malformation \nsyndrome, strongly activates Abl by breaking a salt bridge with the KD C-lobe \nand thereby increasing the force onto the SH2 domain."
    explanation: >
      Defines the physical mechanism by which this CHDSKM allele relieves
      autoinhibition.
pathophysiology:
- name: ABL1 Autoinhibitory Regulatory Core Disruption
  biological_scale: MOLECULAR
  description: >
    Wild-type ABL1 is held in a low-activity state by an assembled
    SH3-SH2-kinase regulatory core. Three intramolecular "linchpins" enforce
    this: docking of the SH3 domain onto the SH2-kinase linker, insertion of
    the N-terminal myristoyl group of isoform 1b into a pocket in the kinase
    domain, and an N-terminal brace over the SH3-SH2 unit. The CHDSKM missense
    substitutions whose position has been mapped fall in these regulatory
    elements - four of the five alleles in the largest functionally
    characterised series lie in the myristoyl-binding pocket, with others in the
    SH2-kinase linker and the C-terminal alpha-I helix - and destabilise the
    assembled core. Several later-reported alleles (p.Trp67Arg, p.Thr136Met,
    p.Gln300Glu, p.Ile508Leu) have not been assigned to a defined autoinhibitory
    element by their source reports, so the clustering claim is scoped to the
    characterised alleles. This is the same autoinhibition failure that the somatic BCR::ABL1
    fusion achieves by deleting the myristoylated N-terminus, which is why the
    two conditions share a molecular logic while remaining entirely distinct
    diseases.
  molecular_functions:
  - preferred_term: ABL1 non-receptor tyrosine kinase activity
    term:
      id: GO:0004715
      label: non-membrane spanning protein tyrosine kinase activity
    modifier: INCREASED
  gene:
    preferred_term: ABL1
    term:
      id: hgnc:76
      label: ABL1
  downstream:
  - target: Constitutive ABL1 Tyrosine Kinase Hyperactivity
    causal_link_type: DIRECT
    description: >
      Loss of autoinhibition is the direct cause of the elevated kinase
      activity, not merely a correlate: the same variants that disrupt the
      regulatory elements are the ones that raise catalytic output.
    evidence:
    - reference: PMID:33223528
      reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "These results are consistent with gain of ABL1 tyrosine kinase activity due to loss of auto-inhibition by myristoyl binding."
      explanation: >
        States the causal link itself - loss of autoinhibition producing the
        gain of kinase activity - rather than either endpoint alone.
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: COMPUTATIONAL
    snippet: "Four of the variants cluster in the \nmyristoyl-binding pocket of ABL1, a region critical for auto-inhibitory \nregulation of the kinase domain."
    explanation: >
      Establishes the myristoyl-binding pocket as the mutational hotspot of the
      four functionally characterised alleles in that series. Tagged
      COMPUTATIONAL because the clustering is an in silico mapping of patient
      variants onto the autoinhibited ABL1 crystal structure (PDB 1OPL),
      combined with missense-constraint and conservation analysis, rather than
      a clinical or wet-lab observation.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Our analysis supports an ABL1 gain-of-function mechanism \ndue to loss of auto-inhibition, and demonstrates the potential for \npharmacological inhibition using imatinib."
    explanation: States the loss-of-autoinhibition gain-of-function mechanism directly.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "As the N-terminus of ABL1 is lost in the fusion product, the auto-inhibitory binding of the myristoyl group to the kinase domain is abolished, and ABL1 gains constitutive tyrosine kinase activity which drives cellular proliferation"
    explanation: >
      Describes the shared autoinhibition-failure logic with BCR::ABL1, the
      mechanistic parallel that motivates the germline gain-of-function model.
  - reference: PMID:38588001
    reference_title: "The molecular basis of Abelson kinase regulation by its αI-helix."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Abelson tyrosine kinase (Abl) is regulated by the arrangement of its regulatory \ncore, consisting sequentially of the SH3, SH2, and kinase (KD) domains, where an \nassembled or disassembled core corresponds to low or high kinase activity, \nrespectively."
    explanation: Defines the assembled-versus-disassembled regulatory core as the activity switch.
- name: Constitutive ABL1 Tyrosine Kinase Hyperactivity
  biological_scale: MOLECULAR
  description: >
    With autoinhibition relieved, the mutant kinase is catalytically more
    active than wild type. This has been demonstrated repeatedly and
    independently: by transient transfection of HEK293T cells with each of the
    reported disease alleles, and by purified-protein biophysics for the
    alpha-I-helix allele p.Glu528Lys. Crucially, the increased activity is
    pharmacologically suppressible - imatinib abolished the excess
    phosphorylation across all tested constructs in vitro, which is the entire
    (preclinical) basis for interest in ABL-directed tyrosine kinase inhibitors
    in this syndrome.
  molecular_functions:
  - preferred_term: ABL1 tyrosine kinase catalytic activity
    term:
      id: GO:0004715
      label: non-membrane spanning protein tyrosine kinase activity
    modifier: INCREASED
  biological_processes:
  - preferred_term: >-
      ABL1 autophosphorylation at Tyr245 (allele-dependent direction; increased
      for myristoyl-pocket alleles, reduced for the SH2-kinase-linker alleles
      p.Val244Ala and p.Tyr245Cys, which activate the kinase independently of
      Tyr245 phosphorylation status)
    term:
      id: GO:0038083
      label: peptidyl-tyrosine autophosphorylation
  downstream:
  - target: Increased Substrate Tyrosine Phosphorylation
    causal_link_type: DIRECT
    description: >
      The elevated kinase activity is measured as, and therefore directly
      produces, increased phosphorylation of ABL1 substrates. The edge is
      reversible in vitro: inhibiting the kinase removes the substrate
      phosphorylation.
    evidence:
    - reference: PMID:33223528
      reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "Phosphorylation of ABL1-Tyr245 and STAT5B were substantially increased in lysates transfected with the c.1066G > A p.(Ala356Thr) construct"
      explanation: >
        Directly couples the variant kinase to increased substrate
        phosphorylation in the same experiment.
    - reference: PMID:33223528
      reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "Treatment with 1 µM imatinib results in complete loss of phosphorylation activity."
      explanation: >
        Pharmacological interruption of the kinase abolishes the downstream
        phosphorylation, supporting the direction of this edge.
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "We overexpressed the mutant constructs in HEK 293T cells and \nobserved increased tyrosine phosphorylation, suggesting increased ABL1 kinase \nactivities associated with both the p.Tyr245Cys and p.Ala356Thr substitutions."
    explanation: Original functional demonstration of increased kinase activity for both founding alleles.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Functional \nwork to investigate ABL1 kinase activity in vitro by transient transfection of \nHEK293T cells with variant ABL1 plasmid constructs revealed increased \nphosphorylation of ABL1-specific substrates compared to wild-type. The increased \ntyrosine kinase activity was suppressed by imatinib treatment."
    explanation: >
      Independent replication across four further alleles, plus the
      imatinib-suppressibility that underpins the ABL-inhibitor hypothesis.
  - reference: PMID:32643838
    reference_title: "The expanding clinical phenotype of germline ABL1-associated congenital heart defects and skeletal malformations syndrome."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Functional investigation of \nthe three novel variants showed an increased ABL1 kinase activity."
    explanation: Third independent laboratory confirming increased kinase activity for new alleles.
- name: Increased Substrate Tyrosine Phosphorylation
  biological_scale: CELLULAR
  description: >
    Hyperactive ABL1 raises global cellular phosphotyrosine and specifically
    hyperphosphorylates canonical ABL1 substrates, of which STAT5/STAT5B is the
    best-characterised readout across all three functional studies. An unbiased
    phosphoproteomic survey of one patient-derived allele additionally found
    increased phosphorylation of UFD1, AXIN1, and ATRX, nominating candidate
    effectors that could link kinase hyperactivity to the cardiac, digital, and
    growth phenotypes - notably UFD1, which the authors relate to the cardiac
    phenotype of 22q11.2 deletion syndrome. These effector assignments are
    hypotheses generated in a cell line, not validated patient-tissue
    mechanisms.
  biological_processes:
  - preferred_term: peptidyl-tyrosine phosphorylation
    term:
      id: GO:0018108
      label: peptidyl-tyrosine phosphorylation
    modifier: INCREASED
  - preferred_term: STAT5 tyrosine phosphorylation
    term:
      id: GO:0007260
      label: tyrosine phosphorylation of STAT protein
    modifier: INCREASED
  downstream:
  - target: Disrupted Cardiac Septation and Outflow Tract Development
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Disrupted Skeletal and Connective Tissue Morphogenesis
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Impaired Prenatal and Postnatal Growth
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Overexpression of the mutant constructs in both isoforms resulted in increased overall phosphotyrosine (p-Tyr) and increased phosphorylation of specific ABL1 substrates (STAT5) when compared to wild-type"
    explanation: Establishes increased global phosphotyrosine and STAT5 phosphorylation as the cellular readout.
  - reference: PMID:33075386
    reference_title: "Phosphorylated proteome analysis of a novel germline ABL1 mutation causing an autosomal dominant syndrome with ventricular septal defect."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Western blotting confirmed that tyrosine phosphorylation in STAT5, a substrate of ABL1, was enhanced, and the novel \nmutation was proved to be a gain-of-function mutation."
    explanation: Independent confirmation of STAT5 hyperphosphorylation for a further patient allele.
  - reference: PMID:33075386
    reference_title: "Phosphorylated proteome analysis of a novel germline ABL1 mutation causing an autosomal dominant syndrome with ventricular septal defect."
    supports: PARTIAL
    evidence_source: IN_VITRO
    snippet: "The proteome analysis showed that \nphosphorylation in proteins such as UFD1, AXIN1, ATRX, which may be involved in \nthe phenotypes, was enhanced in the mutant group."
    explanation: >
      Nominates candidate downstream effectors; the authors themselves frame
      these as hypotheses ("may be involved"), so this supports the node only
      partially.
- name: Disrupted Cardiac Septation and Outflow Tract Development
  biological_scale: TISSUE
  description: >
    Dysregulated ABL1 signalling during cardiac morphogenesis produces
    structural heart disease in the great majority of patients. The reported
    lesions are concentrated at the septa and the left and right outflow tracts:
    atrial and ventricular septal defects, patent ductus arteriosus,
    supravalvular pulmonary stenosis, bicuspid aortic valve, and aortic root
    dilatation. The specific developmental lineage through which kinase
    hyperactivity produces these defects has not been established; the
    phosphoproteomic nomination of UFD1, the 22q11.2 cardiac gene, is the only
    concrete candidate link so far.
  biological_processes:
  - preferred_term: cardiac septum morphogenesis
    term:
      id: GO:0060411
      label: cardiac septum morphogenesis
    modifier: ABNORMAL
  - preferred_term: ventricular septum development
    term:
      id: GO:0003281
      label: ventricular septum development
    modifier: ABNORMAL
  - preferred_term: atrial septum development
    term:
      id: GO:0003283
      label: atrial septum development
    modifier: ABNORMAL
  locations:
  - preferred_term: heart
    term:
      id: UBERON:0000948
      label: heart
  downstream:
  - target: Progressive Aortic Root Dilatation
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The CHD included atrial/ventricular septal defects and in older individuals aortic root dilation."
    explanation: Defines the cardiac lesion spectrum in the founding cohort.
  - reference: PMID:39887622
    reference_title: "A Novel Missense Mutation of the ABL1 Gene in a Child With Congenital Heart Defects and Skeletal Malformations Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The patient was diagnosed with \ncongenital heart defects, including a ventricular septal defect, atrial septal \ndefect, and patent ductus arteriosus."
    explanation: Independent case confirming the septal-plus-ductal lesion pattern.
  - reference: PMID:33075386
    reference_title: "Phosphorylated proteome analysis of a novel germline ABL1 mutation causing an autosomal dominant syndrome with ventricular septal defect."
    supports: PARTIAL
    evidence_source: IN_VITRO
    snippet: "The onset of congenital heart defects associated with this syndrome \nappears to involve a mechanism caused by UFD1 common to 22q.11.2 deletion \nsyndrome."
    explanation: >
      Proposes a specific molecular route from kinase hyperactivity to the
      cardiac defect; hedged by the authors and untested in patient tissue.
- name: Disrupted Skeletal and Connective Tissue Morphogenesis
  biological_scale: TISSUE
  description: >
    The skeletal arm of the syndrome affects the digits most consistently, then
    the axial skeleton and thoracic cage: camptodactyly and finger contractures,
    fifth-finger clinodactyly, 2-3 toe syndactyly, hindfoot deformity,
    scoliosis, and pectus excavatum. A connective-tissue dimension runs in
    parallel - thin skin, joint hypermobility, arachnodactyly, high-arched
    palate, and spontaneous pneumothorax - which is why these patients are
    routinely referred to connective-tissue clinics before the molecular
    diagnosis is made. Notably, the canonical connective-tissue mechanism of
    increased TGF-beta signalling was tested and NOT found: SMAD2 and SMAD3
    phosphorylation were unchanged in the mutant constructs, so CHDSKM does not
    conform to the TGF-beta-dysregulation aortopathy pattern of Marfan and
    Loeys-Dietz syndromes despite the clinical resemblance. That negative is
    the reason this entry declares no conforms_to link to the
    aortopathy_tgfbeta_dysregulation module.
  biological_processes:
  - preferred_term: skeletal system morphogenesis
    term:
      id: GO:0048705
      label: skeletal system morphogenesis
    modifier: ABNORMAL
  downstream:
  - target: Progressive Aortic Root Dilatation
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Common skeletal abnormalities included pectus excavatum, scoliosis, and finger/toe deformities, in particular hindfoot deformity, and finger contractures"
    explanation: Defines the skeletal lesion spectrum.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Phenotypes such as skeletal malformations, aortic root dilatation and pneumothorax point towards an overlap with genetic connective tissue disorders"
    explanation: Documents the connective-tissue dimension of the skeletal phenotype.
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: REFUTE
    evidence_source: IN_VITRO
    snippet: "we did not observe significant alteration in the phosphorylation level of SMAD2 and SMAD3"
    explanation: >
      Directly tests and refutes increased TGF-beta signalling as the
      connective-tissue mechanism, which is why this entry does NOT declare
      conformance to the aortopathy_tgfbeta_dysregulation module.
- name: Progressive Aortic Root Dilatation
  biological_scale: TISSUE
  description: >
    Aortic root enlargement is reported chiefly in older children and adults,
    consistent with a progressive rather than a static congenital lesion, and
    at least one patient has had severe and rapidly progressive dilatation. The
    true risk of aneurysm and dissection is not known: as of the 2021 pooled
    18-case review the authors reported no awareness of any affected individual
    having required surgical intervention for rapid progressive dilatation,
    which they suggested may indicate a more indolent course than Marfan
    syndrome - though a 2023 case has since described exactly that pattern, so
    the indolent-course reading should be treated as provisional. The
    uncertainty itself is the
    clinically actionable point: published expert recommendation is baseline and
    serial aortic root measurement modelled on Marfan surveillance until
    natural-history data exist.
  locations:
  - preferred_term: aortic root
    term:
      id: UBERON:0001496
      label: ascending aorta
  evidence:
  - reference: PMID:36949638
    reference_title: "ABL1-related congenital heart defects and skeletal malformations syndrome in a patient from Sub-Saharan Africa: A case report highlighting novel cardiac features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "he had several features not \npreviously documented, including severe and rapidly progressive aortic root \ndilatation"
    explanation: Documents that aortic root dilatation can be severe and rapidly progressive.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: "Evidence is currently lacking as to the true risk of aortic aneurysm and dissection in this condition. We are not aware of any affected individuals having had rapid progressive aortic dilatation requiring surgical intervention and this may therefore suggest a more indolent course."
    explanation: >
      Qualifies the aortic risk claim - the lesion is real but its natural
      history is undefined and may be more indolent than in Marfan syndrome.
- name: Impaired Prenatal and Postnatal Growth
  biological_scale: ORGANISM
  description: >
    Growth impairment begins prenatally as intrauterine growth restriction and
    continues postnatally as failure to thrive with feeding difficulty. In the
    pooled series failure to thrive is tied with congenital heart disease as the
    third most frequent feature, behind facial dysmorphism and digital
    anomalies. Adult
    stature is variable and does not track the infantile growth failure - most
    adults are short but tall stature has been reported, so short stature is not
    a reliable diagnostic handle.
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Most individuals had failure to thrive during infancy and early childhood"
    explanation: Establishes postnatal growth failure as a core feature.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "failure to thrive (14/18), developmental delay (11/18), IUGR (10/18)"
    explanation: Quantifies both the prenatal and postnatal growth components in the pooled series.
phenotypes:
- category: Craniofacial
  name: Characteristic Facial Dysmorphism
  description: >
    The most consistent single feature of the syndrome, present in every
    described individual. The gestalt is age-dependent: young children have a
    broad forehead, small nose, deep-set eyes, and small chin, while older
    individuals develop an elongated face with a narrow maxilla, a long narrow
    nose, and a pointed chin.
  phenotype_term:
    preferred_term: Characteristic narrow face with pointed chin
    term:
      id: HP:0001999
      label: Abnormal facial shape
    onset:
      onset_category: CONGENITAL
  frequency: VERY_FREQUENT
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The most common clinical features across all described individuals with ABL1 variants are dysmorphic facies (18/18), finger/toe abnormalities (17/18), congenital heart disease (14/18), failure to thrive (14/18), developmental delay (11/18), IUGR (10/18), ear abnormalities (9/18), palatal deformity (9/18) and microcephaly (9/18)"
    explanation: >
      Dysmorphic facies in 18/18 pooled cases (100%) supports the
      VERY_FREQUENT band.
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In younger children, dysmorphic features included a broad forehead, small nose, deep-set eyes, and small chin. In older individuals, the face appeared elongated, with a narrow maxilla, long and narrow nose, and pointed chin"
    explanation: Describes the age-dependent facial gestalt.
- category: Craniofacial
  name: Micrognathia
  description: >
    Micrognathia or microretrognathia with a characteristically small pointed
    chin is a recurrent component of the facial gestalt.
  phenotype_term:
    preferred_term: Micrognathia
    term:
      id: HP:0000347
      label: Micrognathia
  evidence:
  - reference: PMID:39887622
    reference_title: "A Novel Missense Mutation of the ABL1 Gene in a Child With Congenital Heart Defects and Skeletal Malformations Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "distinct \nfacial dysmorphisms such as a broad forehead, frontal bossing, micrognathia, \nlow-set ears, and short palpebral fissures"
    explanation: Micrognathia listed among hallmark facial features.
- category: Craniofacial
  name: Palatal Abnormality
  description: >
    Palatal deformity, most often a high-arched palate, is present in half of
    pooled reported cases and is one of the features that prompts
    consideration of a connective-tissue disorder. The frequency band is
    asserted at the class level because the pooled denominator counts palatal
    deformity generally, not high palate specifically.
  phenotype_term:
    preferred_term: Palatal deformity, usually high-arched palate
    term:
      id: HP:0000174
      label: Abnormal palate morphology
  frequency: FREQUENT
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ear abnormalities (9/18), palatal deformity (9/18) and microcephaly (9/18)"
    explanation: >
      Palatal deformity in 9/18 pooled cases (50%) maps to the FREQUENT band
      (30-79%).
- category: Craniofacial
  name: Ear Malformation
  description: >
    Abnormal external ear morphology - reported as prominent, lobeless, or
    asymmetric ears - occurs in half of pooled reported cases.
  phenotype_term:
    preferred_term: Abnormal ear morphology
    term:
      id: HP:0031703
      label: Abnormal ear morphology
  frequency: FREQUENT
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ear abnormalities (9/18), palatal deformity (9/18) and microcephaly (9/18)"
    explanation: Ear abnormalities in 9/18 pooled cases (50%) maps to the FREQUENT band.
- category: Cardiovascular
  name: Congenital Heart Defect
  description: >
    Structural congenital heart disease is a cardinal manifestation, present in
    all six patients of the founding cohort and in roughly three quarters of
    pooled reported cases. The lesions concentrate at the cardiac septa and the
    outflow tracts.
  phenotype_term:
    preferred_term: Congenital heart defect
    term:
      id: HP:0001627
      label: Abnormal heart morphology
    onset:
      onset_category: CONGENITAL
  frequency: FREQUENT
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "congenital heart disease (14/18), failure to thrive (14/18)"
    explanation: >
      Congenital heart disease in 14/18 pooled cases (78%) maps to the FREQUENT
      band (30-79%).
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "congenital heart disease (CHD, 6/6), skeletal abnormalities (6/6)"
    explanation: Congenital heart disease in all six patients of the founding cohort.
- category: Cardiovascular
  name: Atrial Septal Defect
  description: >
    Interatrial communication, one of the septal lesions that make up the core
    of the CHDSKM cardiac phenotype.
  phenotype_term:
    preferred_term: Atrial septal defect
    term:
      id: HP:0001631
      label: Atrial septal defect
    onset:
      onset_category: CONGENITAL
  evidence:
  - reference: PMID:39887622
    reference_title: "A Novel Missense Mutation of the ABL1 Gene in a Child With Congenital Heart Defects and Skeletal Malformations Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "congenital heart defects, including a ventricular septal defect, atrial septal \ndefect, and patent ductus arteriosus"
    explanation: Documents atrial septal defect in a molecularly confirmed patient.
- category: Cardiovascular
  name: Ventricular Septal Defect
  description: >
    Interventricular communication, the other core septal lesion of the CHDSKM
    cardiac phenotype.
  phenotype_term:
    preferred_term: Ventricular septal defect
    term:
      id: HP:0001629
      label: Ventricular septal defect
    onset:
      onset_category: CONGENITAL
  evidence:
  - reference: PMID:33075386
    reference_title: "Phosphorylated proteome analysis of a novel germline ABL1 mutation causing an autosomal dominant syndrome with ventricular septal defect."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "we found a novel ABL1 mutation in a Japanese family with ventricular septal defect, finger contracture, skin abnormalities and failure to thrive"
    explanation: Ventricular septal defect cosegregating with an ABL1 allele in a multiplex family.
- category: Cardiovascular
  name: Patent Ductus Arteriosus
  description: >
    Persistence of the ductus arteriosus, reported both in the expanded case
    series and in independent single-patient reports.
  phenotype_term:
    preferred_term: Patent ductus arteriosus
    term:
      id: HP:0001643
      label: Patent ductus arteriosus
    onset:
      onset_category: CONGENITAL
  evidence:
  - reference: PMID:39887622
    reference_title: "A Novel Missense Mutation of the ABL1 Gene in a Child With Congenital Heart Defects and Skeletal Malformations Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "congenital heart defects, including a ventricular septal defect, atrial septal \ndefect, and patent ductus arteriosus"
    explanation: Documents patent ductus arteriosus in a molecularly confirmed patient.
- category: Cardiovascular
  name: Aortic Root Dilatation
  description: >
    Aortic root enlargement, reported predominantly in older children and
    adults and capable of severe and rapid progression in at least one
    patient. This is the phenotype that drives the recommendation for lifelong
    echocardiographic surveillance.
  phenotype_term:
    preferred_term: Aortic root dilatation
    term:
      id: HP:0002616
      label: Aortic root aneurysm
    clinical_course: PROGRESSIVE
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The CHD included atrial/ventricular septal defects and in older individuals aortic root dilation."
    explanation: Establishes aortic root dilatation as an age-dependent cardiovascular feature.
  - reference: PMID:36949638
    reference_title: "ABL1-related congenital heart defects and skeletal malformations syndrome in a patient from Sub-Saharan Africa: A case report highlighting novel cardiac features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "severe and rapidly progressive aortic root \ndilatation"
    explanation: Supports the PROGRESSIVE clinical course qualifier.
- category: Cardiovascular
  name: Pulmonic Stenosis
  description: >
    Supravalvular pulmonary stenosis has been reported as part of the outflow
    tract involvement in the expanded case series.
  phenotype_term:
    preferred_term: Supravalvular pulmonary stenosis
    term:
      id: HP:0034349
      label: Supravalvar pulmonary stenosis
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Supra-valvular pulmonary stenosis"
    explanation: Reported cardiac finding in the expanded ABL1 case series.
- category: Skeletal
  name: Finger and Toe Malformations
  description: >
    Digital anomalies are the most consistent skeletal feature and the second
    most consistent feature of the syndrome overall. They include camptodactyly,
    fifth-finger clinodactyly, 2-3 toe syndactyly, tapered or slender fingers,
    and in adults Dupuytren-type contracture.
  phenotype_term:
    preferred_term: Finger and toe abnormalities
    term:
      id: HP:0011297
      label: Abnormal digit morphology
  frequency: VERY_FREQUENT
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "dysmorphic facies (18/18), finger/toe abnormalities (17/18)"
    explanation: >
      Finger/toe abnormalities in 17/18 pooled cases (94%) supports the
      VERY_FREQUENT band.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Some other phenotypic features are also over-represented in our cohort, including camptodactyly (5/6) and microcephaly (5/6)."
    explanation: >
      Camptodactyly, the commonest single digital anomaly, documented in 5 of 6
      patients of the expanded cohort. Note the pooled 17/18 denominator above
      is for digital anomalies as a class, not for camptodactyly specifically,
      which is why the frequency band sits on the class-level term.
- category: Skeletal
  name: Camptodactyly
  description: >
    Fixed flexion deformity of the interphalangeal joints, the single commonest
    digital anomaly of the syndrome. No pooled denominator exists for
    camptodactyly specifically, so no frequency band is asserted here.
  phenotype_term:
    preferred_term: Camptodactyly
    term:
      id: HP:0012385
      label: Camptodactyly
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Some other phenotypic features are also over-represented in our cohort, including camptodactyly (5/6) and microcephaly (5/6)."
    explanation: Camptodactyly in 5 of 6 patients of the expanded case series.
- category: Skeletal
  name: Arachnodactyly
  description: >
    Long slender digits, part of the marfanoid habitus. Diagnostically
    important out of proportion to its frequency: the combination of
    arachnodactyly with blepharophimosis is the stated trigger for
    echocardiography and dual SCARF2/ABL1 testing in the van den Ende-Gupta
    overlap.
  phenotype_term:
    preferred_term: Arachnodactyly
    term:
      id: HP:0001166
      label: Arachnodactyly
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Camptodactyly of fingers, arachnodactyly"
    explanation: >
      Arachnodactyly recorded in the finger/toe abnormality row of the case
      series clinical-features table.
- category: Ophthalmologic
  name: Ocular Abnormalities
  description: >
    Ocular findings were added to the CHDSKM spectrum by the expanded series,
    which described them as distinct but did not enumerate them in the
    abstract. Individually documented findings across cohorts include deep-set
    eyes, almond-shaped eyes with epiblepharon, epicanthic folds, and ptosis
    with proptosis. Frequencies are not robust and no band is asserted.
  phenotype_term:
    preferred_term: Ocular abnormality
    term:
      id: HP:0000478
      label: Abnormality of the eye
  evidence:
  - reference: PMID:32643838
    reference_title: "The expanding clinical phenotype of germline ABL1-associated congenital heart defects and skeletal malformations syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "thereby expanding the phenotypic spectrum of CHDSKM to include hearing impairment, lipodystrophy-like features, renal hypoplasia, and distinct ocular abnormalities."
    explanation: Adds distinct ocular abnormalities to the documented CHDSKM spectrum.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Almond-shaped eyes, epiblepharon"
    explanation: >
      Specific ocular findings recorded in the eyes row of the case-series
      clinical-features table.
- category: Metabolic
  name: Lipodystrophy-Like Features
  description: >
    Lipodystrophy-like features were reported as part of the phenotypic
    expansion of CHDSKM. The source characterises them only as
    "lipodystrophy-like" without further quantification, so this is recorded as
    a documented but unquantified feature.
  phenotype_term:
    preferred_term: Lipodystrophy-like features
    term:
      id: HP:0009125
      label: Lipodystrophy
  evidence:
  - reference: PMID:32643838
    reference_title: "The expanding clinical phenotype of germline ABL1-associated congenital heart defects and skeletal malformations syndrome."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: "thereby expanding the phenotypic spectrum of CHDSKM to include hearing impairment, lipodystrophy-like features, renal hypoplasia, and distinct ocular abnormalities."
    explanation: >
      The source says "lipodystrophy-like", not frank lipodystrophy, so the HP
      term is an approximation and the evidence is PARTIAL.
- category: Skeletal
  name: Finger Contracture
  description: >
    Fixed flexion contractures of the fingers, present from the founding cohort
    onwards and cosegregating with the ABL1 allele in a multiplex family.
  phenotype_term:
    preferred_term: Finger joint contracture
    term:
      id: HP:0034681
      label: Finger joint contracture
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Common skeletal abnormalities included pectus excavatum, scoliosis, and finger/toe deformities, in particular hindfoot deformity, and finger contractures"
    explanation: Finger contractures listed among the common skeletal abnormalities.
- category: Skeletal
  name: Toe Syndactyly
  description: Cutaneous 2-3 toe syndactyly, reported in the expanded case series.
  phenotype_term:
    preferred_term: Toe syndactyly
    term:
      id: HP:0001770
      label: Toe syndactyly
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "2–3 toe syndactyly, camptodactyly of fingers, clinodactyly of 5th fingers"
    explanation: Documents toe syndactyly among digital anomalies in the case series.
- category: Skeletal
  name: Clinodactyly of the Fifth Finger
  description: Incurving of the fifth finger, a recurrent digital anomaly in the syndrome.
  phenotype_term:
    preferred_term: Clinodactyly of the 5th finger
    term:
      id: HP:0004209
      label: Clinodactyly of the 5th finger
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Camptodactyly, clinodactyly of 5th finger, slender fingers"
    explanation: Fifth-finger clinodactyly documented in the expanded case series.
- category: Skeletal
  name: Scoliosis
  description: >
    Lateral curvature of the spine, sometimes severe enough to require surgical
    correction.
  phenotype_term:
    preferred_term: Scoliosis
    term:
      id: HP:0002650
      label: Scoliosis
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Common skeletal abnormalities included pectus excavatum, scoliosis, and finger/toe deformities"
    explanation: Scoliosis among the common skeletal abnormalities of the founding cohort.
  - reference: PMID:39887622
    reference_title: "A Novel Missense Mutation of the ABL1 Gene in a Child With Congenital Heart Defects and Skeletal Malformations Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Skeletal malformations included scoliosis and finger contractures."
    explanation: Independent confirmation in a molecularly confirmed patient.
- category: Skeletal
  name: Pectus Excavatum
  description: >
    Depression of the sternum, part of the marfanoid thoracic-cage phenotype
    that prompts referral to connective-tissue clinics.
  phenotype_term:
    preferred_term: Pectus excavatum
    term:
      id: HP:0000767
      label: Pectus excavatum
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Common skeletal abnormalities included pectus excavatum, scoliosis"
    explanation: Pectus excavatum among the common skeletal abnormalities.
- category: Musculoskeletal
  name: Joint Hypermobility
  description: >
    Joint hyper-extensibility or laxity, reported in three of the six patients
    of the founding cohort and independently in an adult diagnosed via a
    connective-tissue gene panel.
  phenotype_term:
    preferred_term: Joint hypermobility
    term:
      id: HP:0001382
      label: Joint hypermobility
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Three patients had joint hyper-extensibility/laxity."
    explanation: Joint laxity in 3 of 6 patients of the founding cohort.
  - reference: PMID:41416177
    reference_title: "Congenital Heart Defects and Skeletal Malformations Syndrome (CHDSKM) Associated with the ABL1 Gene in a Peruvian patient: Case Report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "he revealed a history of \nskeletal malformations in the hands and joint hypermobility"
    explanation: Independent adult case with joint hypermobility.
- category: Growth
  name: Failure to Thrive
  description: >
    Postnatal growth failure with feeding difficulty during infancy and early
    childhood, one of the three defining features named in the original
    description of the syndrome.
  phenotype_term:
    preferred_term: Failure to thrive
    term:
      id: HP:0001508
      label: Failure to thrive
    onset:
      onset_category: INFANTILE
  frequency: FREQUENT
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "congenital heart disease (14/18), failure to thrive (14/18), developmental delay (11/18)"
    explanation: >
      Failure to thrive in 14/18 pooled cases (78%) maps to the FREQUENT band
      (30-79%).
- category: Growth
  name: Intrauterine Growth Restriction
  description: >
    Prenatal-onset growth restriction, present in about half of pooled reported
    cases, establishing that the growth phenotype begins before birth.
  phenotype_term:
    preferred_term: Intrauterine growth retardation
    term:
      id: HP:0001511
      label: Intrauterine growth retardation
    onset:
      onset_category: ANTENATAL
  frequency: FREQUENT
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "developmental delay (11/18), IUGR (10/18), ear abnormalities (9/18)"
    explanation: >
      IUGR in 10/18 pooled cases (56%) maps to the FREQUENT band (30-79%).
- category: Growth
  name: Short Stature
  description: >
    Short stature is the usual but not universal adult growth outcome; tall
    stature has been reported in a minority, so stature is not a reliable
    discriminator.
  phenotype_term:
    preferred_term: Short stature
    term:
      id: HP:0004322
      label: Short stature
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: "Interestingly, two individuals have tall stature, in contrast to short stature in the majority of cases."
    explanation: >
      Supports short stature as the majority outcome while explicitly
      documenting the tall-stature exception; hence PARTIAL.
- category: Neurologic
  name: Developmental Delay
  description: >
    Developmental delay, usually mild, occurs in a majority of reported
    patients, though some individuals have entirely normal development. Where
    graded in the expanded series it ranged from absent through mild to
    moderate global delay, with one patient described as mainly motor.
  phenotype_term:
    preferred_term: Global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay
  frequency: FREQUENT
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "failure to thrive (14/18), developmental delay (11/18), IUGR (10/18)"
    explanation: >
      Developmental delay in 11/18 pooled cases (61%) maps to the FREQUENT band
      (30-79%).
- category: Neurologic
  name: Microcephaly
  description: >
    Reduced head circumference, recognised as a common feature only after the
    expanded case series, where it was present in five of six new patients and
    half of all pooled cases.
  phenotype_term:
    preferred_term: Microcephaly
    term:
      id: HP:0000252
      label: Microcephaly
  frequency: FREQUENT
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "This case series of six new patients with germline heterozygous ABL1 missense variants further delineates the phenotypic spectrum of this condition and recognises microcephaly \nas a common finding."
    explanation: Establishes microcephaly as a recognised common feature of the syndrome.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "palatal deformity (9/18) and microcephaly (9/18)"
    explanation: Microcephaly in 9/18 pooled cases (50%) maps to the FREQUENT band.
- category: Auditory
  name: Hearing Impairment
  description: >
    Hearing impairment, most often conductive or mixed conductive and
    sensorineural, was recognised as a common feature only after the initial
    description. It can be severe and persistent, and its frequency is the
    stated reason that audiological assessment is recommended for every newly
    diagnosed patient.
  phenotype_term:
    preferred_term: Conductive or mixed hearing impairment
    term:
      id: HP:0000365
      label: Hearing impairment
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All the affected individuals in this series recapitulate the phenotype of the ABL1 \ndevelopmental syndrome and additionally we affirm that hearing impairment is a \ncommon feature of the condition."
    explanation: Establishes hearing impairment as a recognised feature of the syndrome.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "four of our cohort exhibit conductive or mixed conductive/sensorineural hearing impairment, which was severe and persistent in one patient"
    explanation: Specifies the conductive/mixed character of the hearing loss.
  - reference: PMID:32643838
    reference_title: "The expanding clinical phenotype of germline ABL1-associated congenital heart defects and skeletal malformations syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "thereby expanding the phenotypic spectrum of CHDSKM to include hearing impairment, lipodystrophy-like features, renal hypoplasia, and distinct ocular abnormalities."
    explanation: Independent series adding hearing impairment to the CHDSKM spectrum.
- category: Renal
  name: Renal Hypoplasia
  description: >
    Renal hypoplasia (and, in one reported patient, unilateral renal agenesis)
    is an uncommon but reproducible extra-cardiac malformation that justifies
    baseline renal imaging.
  phenotype_term:
    preferred_term: Renal hypoplasia
    term:
      id: HP:0000089
      label: Renal hypoplasia
  evidence:
  - reference: PMID:32643838
    reference_title: "The expanding clinical phenotype of germline ABL1-associated congenital heart defects and skeletal malformations syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "expanding the phenotypic spectrum of CHDSKM to include hearing impairment, lipodystrophy-like features, renal hypoplasia, and distinct ocular abnormalities."
    explanation: Adds renal hypoplasia to the documented CHDSKM phenotype spectrum.
- category: Genitourinary
  name: Hypospadias
  description: >
    Male genital anomalies - hypospadias or hypogonadism - were reported in
    three of the four affected males of the founding cohort.
  phenotype_term:
    preferred_term: Hypospadias
    term:
      id: HP:0000047
      label: Hypospadias
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Hypospadias/hypogonadism was reported in three of four male patients."
    explanation: Documents male genital anomalies in three of four males.
- category: Gastrointestinal
  name: Gastrointestinal Dysmotility and Reflux
  description: >
    Gastrointestinal problems affected five of six patients in the founding
    cohort. One later patient had gastro-oesophageal reflux secondary to
    oesophageal dysmotility with gastric strictures, and another had intestinal
    malrotation.
  phenotype_term:
    preferred_term: Gastrointestinal dysmotility
    term:
      id: HP:0002579
      label: Gastrointestinal dysmotility
  evidence:
  - reference: PMID:36949638
    reference_title: "ABL1-related congenital heart defects and skeletal malformations syndrome in a patient from Sub-Saharan Africa: A case report highlighting novel cardiac features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "gastro-intestinal reflux secondary to esophageal dysmotility \nwith gastric strictures"
    explanation: Documents oesophageal dysmotility as the basis of reflux in a CHDSKM patient.
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "gastrointestinal problems (5/6)"
    explanation: Gastrointestinal involvement in five of six patients of the founding cohort.
- category: Dermatologic
  name: Thin Skin
  description: >
    Thin skin, part of the connective-tissue dimension of the phenotype that
    drives referral to connective-tissue clinics.
  phenotype_term:
    preferred_term: Thin skin
    term:
      id: HP:0000963
      label: Thin skin
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "SkinThin skinYesYesYes"
    explanation: >
      Thin skin recorded as present in three patients in the clinical-features
      table of the expanded case series; the quoted string is the table row
      label plus its patient values as they appear in the cached full text.
- category: Respiratory
  name: Spontaneous Pneumothorax
  description: >
    Spontaneous pneumothorax, sometimes recurrent, is an uncommon but
    diagnostically important manifestation: it is one of the features that
    places CHDSKM in the differential of heritable connective-tissue disease,
    and in at least one patient recurrent pneumothorax was the presenting
    complaint that led to the molecular diagnosis.
  phenotype_term:
    preferred_term: Spontaneous pneumothorax
    term:
      id: HP:0002108
      label: Spontaneous pneumothorax
  evidence:
  - reference: PMID:41416177
    reference_title: "Congenital Heart Defects and Skeletal Malformations Syndrome (CHDSKM) Associated with the ABL1 Gene in a Peruvian patient: Case Report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We present the clinical case of a 20-year-old male patient who presented \nrecurrent pneumothorax on 5 occasions"
    explanation: Recurrent pneumothorax as the presenting feature of a molecularly confirmed CHDSKM patient.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Phenotypes such as skeletal malformations, aortic root dilatation and pneumothorax point towards an overlap with genetic connective tissue disorders"
    explanation: Places pneumothorax within the connective-tissue overlap of the syndrome.
treatments:
- name: Surgical or Catheter Repair of Congenital Heart Defects
  description: >
    Defect-specific management of septal defects, patent ductus arteriosus, and
    outflow tract lesions by paediatric or adult congenital cardiology,
    following standard congenital heart disease practice. There is no
    CHDSKM-specific cardiac surgical protocol; the lesions are managed on their
    own merits.
  action_category: THERAPEUTIC
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: cardiac surgical procedure
    term:
      id: NCIT:C157806
      label: Cardiac Surgery
  target_phenotypes:
  - preferred_term: Atrial septal defect
    term:
      id: HP:0001631
      label: Atrial septal defect
  - preferred_term: Ventricular septal defect
    term:
      id: HP:0001629
      label: Ventricular septal defect
  - preferred_term: Patent ductus arteriosus
    term:
      id: HP:0001643
      label: Patent ductus arteriosus
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: "The CHD included atrial/ventricular septal defects and in older individuals aortic root dilation."
    explanation: >
      Establishes the repairable lesion set that this treatment addresses. No
      CHDSKM-specific surgical series or outcome data exist, so this is
      indication evidence only and supports no efficacy claim; the lesions are
      managed under general congenital heart disease practice.
- name: Aortic Root Surveillance by Serial Echocardiography
  description: >
    Baseline measurement of the aortic root diameter at diagnosis and ongoing
    serial imaging, explicitly modelled on Marfan syndrome surveillance. The
    expert recommendation is explicitly precautionary: the true risk of
    aneurysm and dissection in CHDSKM is unknown, and as of the 2021 pooled
    series no patient had been reported to require surgical intervention for
    rapid progressive dilatation. A 2023 case has since documented severe and
    rapidly progressive dilatation, which strengthens rather than weakens the
    case for surveillance; the recommendation stands until natural-history data
    become available.
  action_category: MONITORING
  treatment_term:
    preferred_term: echocardiography
    term:
      id: NCIT:C16525
      label: Echocardiography Test
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Furthermore, assessment of the aortic root diameter at the time of diagnosis may also be appropriate in individuals found to have pathogenic ABL1 variants."
    explanation: Direct expert recommendation for baseline aortic root assessment.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "a precautionary approach of ongoing aortic root screening similar to that used for Marfan syndrome may be appropriate until such time as more accurate natural history data are available"
    explanation: States the Marfan-modelled, explicitly precautionary basis for serial surveillance.
  - reference: PMID:36949638
    reference_title: "ABL1-related congenital heart defects and skeletal malformations syndrome in a patient from Sub-Saharan Africa: A case report highlighting novel cardiac features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "lend strength to previous calls for close surveillance of the aortic \nroot from a young age in CHDSKM"
    explanation: Independent case reinforcing early and close aortic root surveillance.
- name: Audiological Assessment and Hearing Rehabilitation
  description: >
    Formal audiology at diagnosis and thereafter, with hearing aids or ENT
    intervention as indicated. The rationale is the high frequency of
    conductive and mixed hearing impairment in the syndrome, which was
    under-recognised in the original description. No NCIT clinical-action term
    for audiological assessment is reachable from NCIT:C25218, so this
    treatment carries a free-text preferred_term only.
  action_category: SCREENING
  treatment_term:
    preferred_term: audiological assessment
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The high prevalence of hearing impairment makes audiological assessment advisable."
    explanation: Direct expert recommendation for audiological assessment in CHDSKM.
- name: Nutritional Support for Failure to Thrive
  description: >
    Nutritional and feeding management during infancy and early childhood,
    addressing the feeding difficulties and growth failure that affect most
    patients. Supportive rather than disease-modifying.
  action_category: THERAPEUTIC
  treatment_term:
    preferred_term: nutritional support
    term:
      id: NCIT:C15433
      label: Nutritional Support
  target_phenotypes:
  - preferred_term: Failure to thrive
    term:
      id: HP:0001508
      label: Failure to thrive
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: "Most individuals had failure to thrive during infancy and early childhood"
    explanation: >
      Establishes the clinical need being addressed; no CHDSKM-specific
      nutritional intervention study exists, so this is indication evidence
      only.
- name: Orthopaedic Management of Scoliosis and Contractures
  description: >
    Spinal surveillance with bracing or surgical correction for progressive
    scoliosis, and physiotherapy, occupational therapy, or surgery for finger
    contractures, camptodactyly, and foot deformity. At least one reported
    patient required surgical intervention for scoliosis.
  action_category: THERAPEUTIC
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: orthopedic surgical procedure
    term:
      id: NCIT:C16186
      label: Orthopedic Surgical Procedure
  target_phenotypes:
  - preferred_term: Scoliosis
    term:
      id: HP:0002650
      label: Scoliosis
  - preferred_term: Finger joint contracture
    term:
      id: HP:0034681
      label: Finger joint contracture
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: "ScoliosisYes (surgical intervention)"
    explanation: >
      Table entry recording surgical intervention for scoliosis in a CHDSKM
      patient; establishes the practice, not an efficacy claim.
- name: Developmental and Rehabilitative Therapy
  description: >
    Physical, occupational, and speech and language therapy with developmental
    paediatric follow-up, indicated by the developmental delay present in a
    majority of reported patients and by the hand-function consequences of
    camptodactyly and finger contractures. Supportive; there is no
    CHDSKM-specific rehabilitation protocol or outcome study.
  action_category: THERAPEUTIC
  therapeutic_modality: BEHAVIORAL
  treatment_term:
    preferred_term: physical therapy
    term:
      id: NCIT:C15302
      label: Physical Therapy
  target_phenotypes:
  - preferred_term: Global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: "failure to thrive (14/18), developmental delay (11/18), IUGR (10/18)"
    explanation: >
      Establishes the developmental-delay burden that this supportive care
      addresses; indication evidence only, with no efficacy claim.
- name: ABL-Directed Tyrosine Kinase Inhibition (Investigational)
  description: >
    NOT an established treatment. Imatinib abolishes the excess phosphorylation
    of mutant ABL1 constructs in vitro, which makes the gain-of-function
    mechanism pharmacologically tractable in principle and is the sole basis for
    interest in ABL-directed tyrosine kinase inhibitors here. The authors of
    that work do advance a therapeutic hypothesis: because the germline alleles
    functionally mimic the loss of the ABL1 N-terminus in BCR-ABL, they expect
    TKIs effective against BCR-ABL to be similarly effective against the variant
    proteins, and they raise limiting aortic root dilatation as a candidate
    indication. Three considerations nevertheless weigh against clinical use
    outside a rigorously justified research protocol. First, the malformations
    arise during embryofetal development, so any meaningful effect would require
    treatment from a very early age and lifelong exposure. Second, imatinib is
    expected to be teratogenic in pregnancy, and severe congenital malformations
    have been reported in fetuses exposed to it - though the original authors
    caution that no definitive conclusion about imatinib teratogenicity can be
    drawn from the small number of cases, several of which also involved
    exposure to other teratogens such as warfarin or hydroxyurea. Third,
    structural work shows that type II ATP-site inhibitors such as imatinib
    promote disassembly of the very regulatory core whose disassembly drives the
    disease, whereas the allosteric myristoyl-pocket inhibitor asciminib
    stabilises the alpha-I helix instead - so the two inhibitor classes are not
    interchangeable and leukaemia dosing cannot simply be transplanted into a
    developmental syndrome.
  action_category: THERAPEUTIC
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: imatinib
      term:
        id: CHEBI:45783
        label: imatinib
  target_mechanisms:
  - target: Constitutive ABL1 Tyrosine Kinase Hyperactivity
    treatment_effect: INHIBITS
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: PARTIAL
    evidence_source: IN_VITRO
    snippet: "Finally, as expected, imatinib abolished phosphorylation of ABL1-Tyr245 and STAT5B in all of the constructs"
    explanation: >
      In vitro pharmacological tractability only; no clinical evidence of
      benefit in CHDSKM, hence PARTIAL.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: PARTIAL
    evidence_source: OTHER
    snippet: "While imatinib is used to treat paediatric CML cases, it is expected to be teratogenic in pregnancy. Further work is therefore required to ascertain whether therapeutic scope exists for use of imatinib or similar TKIs in this condition."
    explanation: >
      The authors' own caveat, stated as expert discussion rather than as a
      reported observation: teratogenicity risk and absence of evidence for
      therapeutic scope in this condition.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: PARTIAL
    evidence_source: OTHER
    snippet: "TKIs may potentially in some way be therapeutically beneficial for the ABL1 developmental syndrome or its complications, for example in limiting aortic root dilatation or reducing the tendency for dilatation to occur."
    explanation: >
      The therapeutic hypothesis the same authors advance, recorded alongside
      their cautions so the entry reflects both halves of the source argument.
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: "severe congenital malformations have been reported in fetuses exposed to imatinib, a selective tyrosine kinase inhibitor drug"
    explanation: >
      Documents the fetal malformation signal that makes developmental use of
      this drug class hazardous. PARTIAL because the same paragraph states that
      no definitive conclusion about imatinib teratogenicity can be drawn from
      the small, confounded case set.
  - reference: PMID:38588001
    reference_title: "The molecular basis of Abelson kinase regulation by its αI-helix."
    supports: PARTIAL
    evidence_source: IN_VITRO
    snippet: "In contrast, the \nallosteric inhibitor asciminib strongly reduces Abl's activity by fixating the \nαI-helix and reducing the force onto the SH2 domain."
    explanation: >
      Supports the mechanistic distinction between allosteric and type II
      ATP-site inhibition that complicates drug selection in this syndrome.
- name: Malignancy Screening
  description: >
    Systematic clinical screening for ABL1-associated cancers, recommended by
    the authors of the original description on the precautionary grounds that
    the germline alleles increase the activity of a proto-oncogene. This is a
    prudential recommendation, not an evidence-based protocol: no malignancy
    has been reported in any CHDSKM patient, no screening modality or interval
    has been specified or validated, and the lifetime risk is unquantified.
    The corresponding evidence gap is tracked in the chdskm_malignancy_risk
    discussion.
  action_category: SCREENING
  treatment_term:
    preferred_term: cancer screening
    term:
      id: NCIT:C15406
      label: Cancer Screening
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: "Malignancies have not been detected in any of the affected individuals with ABL1 germline variants, but as they cause increased phosphorylation and possibly increased kinase activity of this proto-oncogene, it may be prudent to perform systematic clinical screening for ABL1-associated cancers in the newly identified individuals."
    explanation: >
      The recommendation and its explicitly prudential, unvalidated basis, both
      stated in the same sentence; PARTIAL because no risk estimate, modality,
      or interval is given.
- name: Baseline Renal Imaging
  description: >
    Renal ultrasound at diagnosis, indicated by the renal hypoplasia added to
    the CHDSKM spectrum by the expanded series and by the unilateral renal
    agenesis recorded in the case-series table. Detection-oriented; no
    CHDSKM-specific screening interval has been defined.
  action_category: SCREENING
  treatment_term:
    preferred_term: renal ultrasound
    term:
      id: NCIT:C159885
      label: Renal Ultrasound
  evidence:
  - reference: PMID:32643838
    reference_title: "The expanding clinical phenotype of germline ABL1-associated congenital heart defects and skeletal malformations syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "expanding the phenotypic spectrum of CHDSKM to include hearing impairment, lipodystrophy-like features, renal hypoplasia, and distinct ocular abnormalities."
    explanation: Renal hypoplasia in the documented spectrum is the indication for baseline renal imaging.
- name: Baseline Ophthalmologic Evaluation
  description: >
    Eye examination at diagnosis, indicated by the distinct ocular
    abnormalities added to the CHDSKM spectrum by the expanded series. The
    source does not enumerate the findings in its abstract, so this is a
    detection-oriented baseline rather than a search for a specified lesion.
  action_category: SCREENING
  treatment_term:
    preferred_term: eye examination
    term:
      id: NCIT:C38060
      label: Eye Examination
  evidence:
  - reference: PMID:32643838
    reference_title: "The expanding clinical phenotype of germline ABL1-associated congenital heart defects and skeletal malformations syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "expanding the phenotypic spectrum of CHDSKM to include hearing impairment, lipodystrophy-like features, renal hypoplasia, and distinct ocular abnormalities."
    explanation: Distinct ocular abnormalities in the documented spectrum are the indication for baseline eye examination.
- name: Genetic Counseling and Cascade Testing
  description: >
    Counseling for the recurrence risk from an affected heterozygous parent,
    with cascade testing of at-risk relatives once a familial variant is
    identified. Because the condition is autosomal dominant, each pregnancy of
    an affected heterozygous parent carries a one-in-two transmission risk; the
    documented father-to-child and mother-to-child transmissions of p.Tyr245Cys
    make this a real rather than theoretical counseling scenario. Counseling
    must convey that expressivity is variable, so severity in an affected child
    cannot be predicted from the parent's phenotype, and that most probands to
    date have carried de novo variants. Once a familial variant is known,
    prenatal diagnosis and preimplantation genetic testing for monogenic
    disease are technically available reproductive options.
  action_category: COUNSELING_INFORMATIONAL
  treatment_term:
    preferred_term: genetic counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In family 3, p.Tyr245Cys was found to be inherited from the similarly affected father."
    explanation: >
      Documented parent-to-child transmission establishes the recurrence risk
      that genetic counseling addresses.
diagnosis:
- name: Exome or Genome Sequencing Identifying a Heterozygous ABL1 Missense Variant
  description: >
    There are no consensus clinical diagnostic criteria and no biochemical
    biomarker for CHDSKM; diagnosis is molecular. Both the founding cohort and
    the expanded series were identified by exome sequencing after targeted
    testing for known disease genes was negative. The practical trigger for
    testing is syndromic congenital heart disease plus digital or skeletal
    anomalies with the characteristic narrow facies and growth restriction.
    Interpretation should weigh whether the missense allele lies in a known
    autoinhibitory region consistent with the gain-of-function mechanism;
    functional kinase assays remain research tools, not validated clinical
    tests.
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Exome sequencing and Sanger fill-in of regions poorly covered by exome sequencing did not identify any causal variants in known disease genes"
    explanation: Establishes exome sequencing as the diagnostic route in the founding cohort.
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Here, we describe a series of \nsix new unrelated individuals with heterozygous missense variants in ABL1 \n(including four novel variants) identified via whole exome sequencing."
    explanation: Confirms exome sequencing as the diagnostic modality in the expanded series.
differential_diagnoses:
- name: Marfan Syndrome
  description: >
    The marfanoid habitus, arachnodactyly, joint laxity, high-arched palate,
    aortic root dilatation, and spontaneous pneumothorax of CHDSKM overlap
    Marfan syndrome closely enough that Marfan was the working differential
    diagnosis in one of the four founding families, and CHDSKM patients are
    still reached through connective-tissue gene panels.
  disease_term:
    preferred_term: Marfan syndrome
    term:
      id: MONDO:0007947
      label: Marfan syndrome
  distinguishing_features:
  - CHDSKM adds congenital septal heart defects, digital contractures and camptodactyly, intrauterine growth restriction and failure to thrive, microcephaly, and hearing impairment, none of which are Marfan features.
  - Ectopia lentis, a cardinal Marfan diagnostic feature, has not been reported in any published CHDSKM patient, although "distinct ocular abnormalities" of unspecified type are part of the CHDSKM spectrum, so this discriminator should be applied with care.
  - The TGF-beta dysregulation that characterises FBN1-related aortopathy was tested in CHDSKM and not found (SMAD2/SMAD3 phosphorylation unchanged).
  - Causal gene ABL1 rather than FBN1.
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Due to cardiac and skeletal manifestations, differential diagnoses commonly included connective tissue disorders, e.g. Marfan syndrome in families 3."
    explanation: Marfan syndrome was the clinical differential in a founding CHDSKM family.
- name: Loeys-Dietz Syndrome
  description: >
    Loeys-Dietz syndrome shares the long face, high-arched palate,
    microretrognathia, pectus deformity, scoliosis, arachnodactyly, joint
    laxity, and aortic root aneurysm, and was named alongside
    Shprintzen-Goldberg syndrome as a formal differential in the original
    CHDSKM report.
  disease_term:
    preferred_term: Loeys-Dietz syndrome
    term:
      id: MONDO:0018954
      label: Loeys-Dietz syndrome
  distinguishing_features:
  - Loeys-Dietz is caused by TGFBR1, TGFBR2, SMAD3, TGFB2, or TGFB3 variants with demonstrably dysregulated TGF-beta signalling; CHDSKM shows no SMAD2/SMAD3 phosphorylation change.
  - Loeys-Dietz carries a high risk of aggressive aortic dissection requiring early prophylactic surgery; the CHDSKM aortic natural history is undefined and may be more indolent.
  - Arterial tortuosity, hypertelorism, and bifid uvula are characteristic of Loeys-Dietz and have not been reported in published CHDSKM patients.
  - CHDSKM adds septal defects, digital contractures, growth failure, and hearing loss.
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The differential diagnosis of the newly described syndrome includes Shprintzen-Goldberg syndrome (dolichostenomelia, arachnodactyly, pectus deformity, scoliosis, aortic root enlargement, and high-arched palate) and Loeys-Dietz syndrome"
    explanation: Loeys-Dietz named as a formal differential in the original report.
- name: Van den Ende-Gupta Syndrome
  description: >
    Van den Ende-Gupta syndrome (VDEGS) is the differential that most often
    causes genuine molecular misclassification rather than merely clinical
    confusion: three individuals with classical VDEGS features and negative
    SCARF2 testing were subsequently found to carry pathogenic ABL1 variants,
    and their phenotype was reclassified as CHDSKM.
  disease_term:
    preferred_term: van den Ende-Gupta syndrome
    term:
      id: MONDO:0010959
      label: van den Ende-Gupta syndrome
  distinguishing_features:
  - VDEGS is autosomal recessive and caused by biallelic SCARF2 variants; CHDSKM is autosomal dominant and caused by heterozygous ABL1 gain-of-function missense alleles.
  - The shared clinical handles are arachnodactyly and blepharophimosis with distinctive facial and skeletal features.
  - Because the two overlap, individuals with arachnodactyly plus blepharophimosis should have echocardiography and testing of both SCARF2 and ABL1.
  evidence:
  - reference: PMID:33783941
    reference_title: "Further delineation of van den Ende-Gupta syndrome: Genetic heterogeneity and overlap with congenital heart defects and skeletal malformations syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Three were found to have pathogenic \nABL1 variants using whole exome sequencing (WES) or whole genome sequencing \n(WGS). Their phenotype was consistent with the congenital heart disease and \nskeletal malformations syndrome (CHDSKM), which has been associated with ABL1 \nvariants."
    explanation: Documents actual reclassification of VDEGS-phenotype patients as CHDSKM.
  - reference: PMID:33783941
    reference_title: "Further delineation of van den Ende-Gupta syndrome: Genetic heterogeneity and overlap with congenital heart defects and skeletal malformations syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "individuals with the combination of arachnodactyly and blepharophimosis should undergo \nechocardiography while awaiting results of molecular testing due to the \noverlapping physical features of VDEGS and CHDSKM."
    explanation: States the practical diagnostic consequence of the VDEGS-CHDSKM overlap.
- name: Human ABL1 Deficiency Syndrome
  description: >
    The allelic counterpart of CHDSKM at the same locus. Biallelic
    loss-of-function ABL1 variants cause a distinct recognisable syndrome of
    multiple congenital malformations and facial dysmorphism that is described
    as opposite to CHDSKM in many respects - the clearest possible demonstration
    that ABL1 activity must be held within a narrow band during development, and
    the reason the two must never be merged into one entity.
  distinguishing_features:
  - ABL1 deficiency syndrome is autosomal recessive, arises in consanguineous families, and is caused by homozygous loss-of-function alleles.
  - CHDSKM is autosomal dominant and caused by heterozygous gain-of-function missense alleles.
  - The dysmorphic gestalts are reported as opposite in many features.
  - Molecular reports must therefore state zygosity and predicted functional direction, not merely that an ABL1 variant is present.
  evidence:
  - reference: PMID:38743093
    reference_title: "Human ABL1 deficiency syndrome (HADS) is a recognizable syndrome distinct from ABL1-related congenital heart defects and skeletal malformations syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The associated phenotype is multiple \ncongenital malformations and distinctive facial dysmorphism that are opposite in \nmany ways to CHDSKM. We suggest that a tight balance of ABL1 activity is \nrequired during embryonic development and that both germline gain of function \nand loss of function variants result in distinctively different allelic \ncongenital malformation disorders."
    explanation: Establishes ABL1 deficiency syndrome as a distinct allelic disorder, not a CHDSKM variant.
discussions:
- discussion_id: chdskm_lineage_route_to_malformation
  kind: KNOWLEDGE_GAP
  status: OPEN
  prompt: >
    Through which developmental cell lineages and downstream effectors does
    ABL1 kinase hyperactivity produce the specific CHDSKM malformation set
    (cardiac septa and outflow tract, digits, axial skeleton, aortic root)?
  attaches_to:
  - "pathophysiology#Increased Substrate Tyrosine Phosphorylation"
  - "pathophysiology#Disrupted Cardiac Septation and Outflow Tract Development"
  rationale: >
    Steps 1 to 3 of the causal chain - autoinhibition loss, kinase
    hyperactivity, increased substrate phosphorylation - are experimentally
    solid and independently replicated. The step from generalised
    phosphotyrosine excess to a specific, reproducible malformation pattern is
    entirely inferential. The only concrete effector nominations come from a
    single phosphoproteomic experiment in a transfected cell line (UFD1, AXIN1,
    ATRX), and even the cell types involved - cardiomyocytes, endocardial and
    valvular interstitial cells, cardiac neural crest derivatives,
    chondrocytes, craniofacial mesenchyme - remain plausible candidates rather
    than demonstrated targets. This is why the pathophysiology edges leading
    out of the phosphorylation node are typed INDIRECT_UNKNOWN_INTERMEDIATES
    and why no cell types are asserted on the cardiac node.
  proposed_experiments:
  - experiment_id: chdskm_lineage_restricted_knockin
    name: Lineage-restricted CHDSKM allele knock-in in mouse
    description: >
      Conditional knock-in of a recurrent human allele (p.Tyr245Cys or
      p.Glu528Lys) restricted to cardiac mesoderm, cardiac neural crest,
      endocardium, and limb/skeletal mesenchyme, with staged phenotyping of
      septation and outflow tract development.
    decision_criterion: >
      A lineage in which the knock-in reproduces septal or outflow tract
      defects identifies the cell population through which kinase
      hyperactivity acts.
  - experiment_id: chdskm_ipsc_lineage_phosphoproteomics
    name: Phosphoproteomics in disease-relevant differentiated cell types
    description: >
      Differentiate patient-derived iPSCs to cardiomyocytes and chondrocytes
      and repeat phosphoproteomic profiling in those lineages rather than in
      HEK293T, testing whether UFD1, AXIN1, and ATRX hyperphosphorylation
      reproduces outside the overexpression system.
    decision_criterion: >
      Reproduction of the effector hyperphosphorylation in a developmentally
      relevant lineage would upgrade those nominations from hypothesis to
      candidate mechanism.
  evidence:
  - reference: PMID:33075386
    reference_title: "Phosphorylated proteome analysis of a novel germline ABL1 mutation causing an autosomal dominant syndrome with ventricular septal defect."
    supports: PARTIAL
    evidence_source: IN_VITRO
    snippet: "AXIN1 and ATRX may be important in elucidating the mechanisms of other phenotypes, such as finger contracture and failure to thrive. Verification of these hypotheses would lead to further understanding of the pathophysiology and the development of treatment methods."
    explanation: >
      The authors explicitly frame the effector assignments as unverified
      hypotheses requiring further work.
- discussion_id: chdskm_model_organism_mismatch
  kind: HUMAN_MODEL_MISMATCH
  status: OPEN
  prompt: >
    Do the available Abl1 mouse models, which are all loss-of-function, have
    any translational validity for a human heterozygous gain-of-function
    syndrome?
  attaches_to:
  - "pathophysiology#ABL1 Autoinhibitory Regulatory Core Disruption"
  rationale: >
    Every published Abl1 mouse model is a null or truncation allele. Their
    phenotypes - growth delay, cardiac hyperplasia, osteoporosis, lymphopenia,
    perinatal lethality - establish that ABL1 matters in development but point
    in the opposite functional direction from the human disease. The mismatch
    is not incidental: the original authors specifically re-examined
    ventricular wall thickness in their patients and confirmed the absence of
    the cardiac hyperplasia seen in the knockout mice, attributing the
    difference to increased versus abolished kinase activity. Mouse
    heterozygotes are largely unaffected, so there is no dosage model either.
    No knock-in model of a recurrent human CHDSKM allele has been reported.
  proposed_experiments:
  - experiment_id: chdskm_knockin_versus_null
    name: CHDSKM knock-in mouse compared against Abl1 null
    description: >
      Generate constitutive and conditional knock-in mice carrying the human
      p.Tyr245Cys or p.Glu528Lys allele, assess whether cardiac septal defects,
      digital contractures, growth restriction, and aortic root dilatation are
      recapitulated, and compare directly against Abl1 null animals in the same
      genetic background.
    decision_criterion: >
      Recapitulation of the human malformation set by the knock-in, with a
      phenotype distinct from the null, would establish a valid model and
      confirm the functional direction of the human alleles.
  evidence:
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Abl1 knockout mice have growth delay, cardiac hyperplasia and osteoporosis"
    explanation: Describes the loss-of-function mouse phenotype available as a model.
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: REFUTE
    evidence_source: HUMAN_CLINICAL
    snippet: "We re-evaluated the ventricular wall thickness of our patients and confirmed that there is no cardiac hyperplasia"
    explanation: >
      Explicitly documents that the mouse cardiac phenotype is not reproduced
      in human patients - the core of the model mismatch.
- discussion_id: chdskm_malignancy_risk
  kind: KNOWLEDGE_GAP
  status: OPEN
  prompt: >
    Do germline ABL1 gain-of-function alleles confer an increased lifetime risk
    of haematological or other malignancy?
  attaches_to:
  - "pathophysiology#Constitutive ABL1 Tyrosine Kinase Hyperactivity"
  rationale: >
    ABL1 is a proto-oncogene and its constitutive activation in the somatic
    BCR::ABL1 fusion drives chronic myeloid leukaemia, so a germline activating
    allele raises an obvious question. No malignancy has been reported in any
    CHDSKM patient, but the total described cohort is very small and mostly
    young, so absence of events is weak evidence of absence of risk. There is a
    mechanistic argument for reassurance - disruption of myristoyl binding alone
    may not activate ABL1 enough to drive malignancy because two other
    autoinhibitory linchpins remain intact, whereas BCR::ABL1 loses both the
    myristoyl group and the N-terminal brace - but this is reasoning, not data.
    Notably, the authors of the largest functional series report that none of
    the activating germline variants they describe has been associated with
    somatic tyrosine kinase inhibitor resistance in leukaemia - though one
    residue, Ala452, is shared between the germline and somatic settings, so
    the separation is not absolute.
  proposed_experiments:
  - experiment_id: chdskm_longitudinal_registry
    name: Longitudinal CHDSKM malignancy registry
    description: >
      Establish a prospective registry capturing routine blood counts and
      malignancy events in molecularly confirmed CHDSKM patients into
      adulthood, alongside aortic dimensions, hearing, growth, and
      neurodevelopment.
    decision_criterion: >
      Accumulated person-years without haematological malignancy, or an
      excess of events, would for the first time bound the lifetime risk.
  - experiment_id: chdskm_hspc_transformation_assay
    name: Transformation capacity of germline-allele haematopoietic cells
    description: >
      Assess whether patient-derived or engineered haematopoietic stem and
      progenitor cells carrying the germline CHDSKM alleles show clonal
      advantage or transformation capacity relative to BCR::ABL1-expressing
      controls.
    decision_criterion: >
      Absence of clonal advantage would support the mechanistic argument that
      myristoyl-pocket disruption alone is insufficient for transformation.
  evidence:
  - reference: PMID:33223528
    reference_title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: "No patients with the ABL1 skeletal and cardiac malformation syndrome described here or elsewhere are reported to have haematological malignancy, but longitudinal follow up of these patients will be required to better determine this."
    explanation: States both the absence of observed malignancy and the insufficiency of current follow-up.
  - reference: PMID:28288113
    reference_title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: "Malignancies have not been detected in any of the affected individuals with ABL1 germline variants, but as they cause increased phosphorylation and possibly increased kinase activity of this proto-oncogene, it may be prudent to perform systematic clinical screening for ABL1-associated cancers in the newly identified individuals."
    explanation: >
      The original authors' recommendation for cancer screening in the face of
      unquantified risk.
references:
- reference: PMID:28288113
  title: "Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations."
- reference: PMID:33223528
  title: "Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity."
- reference: PMID:32643838
  title: "The expanding clinical phenotype of germline ABL1-associated congenital heart defects and skeletal malformations syndrome."
- reference: PMID:38588001
  title: "The molecular basis of Abelson kinase regulation by its αI-helix."
- reference: PMID:38743093
  title: "Human ABL1 deficiency syndrome (HADS) is a recognizable syndrome distinct from ABL1-related congenital heart defects and skeletal malformations syndrome."

📚

References & Deep Research

References

5

PMID:28288113

Germline mutations in ABL1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations.

No top-level findings curated for this source.

PMID:33223528

Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity.

No top-level findings curated for this source.

PMID:32643838

The expanding clinical phenotype of germline ABL1-associated congenital heart defects and skeletal malformations syndrome.

No top-level findings curated for this source.

PMID:38588001

The molecular basis of Abelson kinase regulation by its αI-helix.

No top-level findings curated for this source.

PMID:38743093

Human ABL1 deficiency syndrome (HADS) is a recognizable syndrome distinct from ABL1-related congenital heart defects and skeletal malformations syndrome.

No top-level findings curated for this source.

Deep Research

1

Falcon ▸

Disease Characteristics Research Template

Edison Scientific Literature 23 citations 2026-08-01T18:54:11.004190

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Disease Characteristics Research Template

Target Disease

Disease Name: Congenital Heart Defects and Skeletal Malformations Syndrome
MONDO ID: MONDO:0060532,OMIM:617602,gene=ABL1/HGNC:76,acronym=CHDSKM,NOT-Holt-Oram-TBX5,NOT-Ellis-van-Creveld,NOT-VACTERL,NOT-Char-syndrome (if available)
Category: Mendelian

Research Objectives

Please provide a comprehensive research report on Congenital Heart Defects and Skeletal Malformations Syndrome covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.

For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.

1. Disease Information

Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed

What is the disease? Provide a concise overview.
What are the key identifiers? (OMIM, Orphanet, ICD-10/ICD-11, MeSH, Mondo)
What are the common synonyms and alternative names?
Is the information derived from individual patients (e.g., EHR) or aggregated disease-level resources?

2. Etiology

Disease Causal Factors: What are the primary causes? (genetic, environmental, infectious, mechanistic)
Risk Factors:

Search first: PubMed, Cochrane Library, UpToDate, clinical guidelines, ClinVar, ClinGen, GWAS Catalog, PheGenI, CTD, CDC, WHO, epidemiological databases
Genetic risk factors (causal variants, susceptibility loci, modifier genes)
Environmental risk factors (toxins, lifestyle, occupational exposures, age, sex, family history)
Protective Factors:

Search first: PubMed, Cochrane Library, clinical trial databases, GWAS Catalog, gnomAD, WHO, CDC, nutrition databases
Genetic protective factors (protective variants, modifier alleles)
Environmental protective factors (diet, lifestyle, exposures that reduce risk)
Gene-Environment Interactions: How do genetic and environmental factors interact to influence disease?

Search first: CTD, PubMed, PheGenI, GxE databases

3. Phenotypes

Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC

For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities

For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype

4. Genetic/Molecular Information

Causal Genes: Gene mutations or chromosomal abnormalities responsible for disease (gene symbols, OMIM IDs)

Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene
Pathogenic Variants:
Affected genes (gene symbols, HGNC IDs) > Search first: OMIM, NCBI Gene, Ensembl, HGNC, UniProt, GeneCards
Variant classification (pathogenic, likely pathogenic, VUS per ACMG/AMP guidelines) > Search first: ClinVar, ClinGen, ACMG/AMP guidelines, VarSome
Variant type/class (missense, frameshift, nonsense, splice-site, structural)
Allele frequency in population databases > Search first: gnomAD, 1000 Genomes, ExAC, TOPMed, dbSNP
Somatic vs germline origin > Search first: COSMIC (somatic), ClinVar, ICGC, TCGA
Functional consequences (loss of function, gain of function, dominant negative)
Modifier Genes: Genes that modify disease severity or expression
Epigenetic Information: DNA methylation, histone modifications, chromatin changes affecting disease

Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
Chromosomal Abnormalities: Large-scale genetic changes (aneuploidy, translocations, inversions)

Search first: DECIPHER, ClinVar, ECARUCA, UCSC Genome Browser

5. Environmental Information

Environmental Factors: Non-genetic contributing factors (toxins, radiation, pollution, occupational exposure)

Search first: CTD (Comparative Toxicogenomics Database), TOXNET, PubMed, EPA databases
Lifestyle Factors: Behavioral factors (smoking, diet, exercise, alcohol consumption)

Search first: CDC databases, WHO, PubMed, NHANES
Infectious Agents: If applicable, pathogens causing or triggering disease (bacteria, viruses, fungi, parasites)

Search first: NCBI Taxonomy, ViPR, BV-BRC, MicrobeDB, GIDEON

6. Mechanism / Pathophysiology

Molecular Pathways: Specific signaling cascades or biochemical pathways involved (Wnt, MAPK, mTOR, PI3K-AKT, etc.)

Search first: KEGG, Reactome, WikiPathways, PathBank, BioCyc
Cellular Processes: Cell-level mechanisms (apoptosis, autophagy, cell cycle dysregulation, inflammation, etc.)

Search first: Gene Ontology (GO), Reactome, KEGG, PubMed
Protein Dysfunction: How protein structure or function is altered (misfolding, aggregation, loss of function, gain of function)

Search first: UniProt, PDB (Protein Data Bank), InterPro, Pfam, AlphaFold
Metabolic Changes: Alterations in metabolic processes (energy metabolism, lipid metabolism, amino acid metabolism)

Search first: KEGG, BioCyc, HMDB (Human Metabolome Database), BRENDA
Immune System Involvement: Role of immune response (autoimmunity, immunodeficiency, chronic inflammation)

Search first: ImmPort, Immunome Database, IEDB, Gene Ontology
Tissue Damage Mechanisms: How tissues/ are injured (oxidative stress, ischemia, fibrosis, necrosis)

Search first: PubMed, Gene Ontology, Reactome
Biochemical Abnormalities: Specific molecular defects (enzyme deficiencies, receptor dysfunction, ion channel defects)

Search first: BRENDA, UniProt, KEGG, OMIM, PubMed
Epigenetic Changes: DNA methylation, histone modifications affecting gene expression in disease

Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
Molecular Profiling (if available):
Transcriptomics/gene expression changes > Search first: GEO (Gene Expression Omnibus), ArrayExpress, GTEx, Human Cell Atlas, SRA
Proteomics findings > Search first: PRIDE, ProteomeXchange, Human Protein Atlas, STRING, BioGRID
Metabolomics signatures > Search first: MetaboLights, Metabolomics Workbench, HMDB, METLIN
Lipidomics alterations > Search first: LIPID MAPS, SwissLipids, LipidHome, Metabolomics Workbench
Genomic structural features > Search first: UCSC Genome Browser, Ensembl, NCBI, dbVar, DGV
Advanced Technologies (if applicable):
Single-cell analysis findings (cell-type specific mechanisms, cellular heterogeneity) > Search first: Human Cell Atlas, Single Cell Portal, GEO, CELLxGENE
Spatial transcriptomics findings > Search first: GEO, Spatial Research, Vizgen, 10x Genomics data
Multi-omics integration results > Search first: TCGA, ICGC, cBioPortal, LinkedOmics, PubMed
Functional genomics screens (CRISPR, RNAi) > Search first: DepMap, GenomeRNAi, PubMed, BioGRID ORCS

For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types

7. Anatomical Structures Affected

Organ Level:
Primary organs directly affected
Secondary organ involvement (complications, secondary effects)
Body systems involved (cardiovascular, nervous, digestive, respiratory, endocrine, etc.)

Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT
Tissue and Cell Level:
Specific tissue types affected (epithelial, connective, muscle, nervous)
Specific cell populations targeted (with Cell Ontology terms)

Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB
Subcellular Level:
Cellular compartments involved (mitochondria, nucleus, ER, lysosomes) (with GO Cellular Component terms)

Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas
Localization:
Specific anatomical sites (with UBERON terms) > Search first: FMA, Uberon, NeuroNames (for brain), SNOMED CT
Lateralization (unilateral, bilateral, asymmetric) > Search first: HPO, clinical literature, imaging databases

8. Temporal Development

Onset:
Typical age of onset (congenital, pediatric, adult, geriatric)
Onset pattern (acute, subacute, chronic, insidious)

Search first: OMIM, Orphanet, HPO, PubMed
Progression:
Disease stages (early, intermediate, advanced, end-stage) > Search first: Cancer Staging Manual (AJCC), WHO classifications, PubMed
Progression rate (rapid, slow, variable)
Disease course pattern (episodic, relapsing-remitting, progressive, stable)
Disease duration (self-limited, chronic lifelong)

Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM
Patterns:
Remission patterns (spontaneous, treatment-induced) > Search first: Clinical trial databases, disease registries, PubMed
Critical periods (time windows of vulnerability or opportunity for intervention) > Search first: PubMed, developmental biology databases, clinical guidelines

9. Inheritance and Population

Epidemiology:
Prevalence (cases per 100,000 at given time)
Incidence (new cases per 100,000 per year)

Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries
For Genetic Etiology:
Inheritance pattern (AD, AR, X-linked, mitochondrial, multifactorial, polygenic) > Search first: OMIM, Orphanet, ClinVar, GTR (Genetic Testing Registry)
Penetrance (complete, incomplete, age-dependent) > Search first: ClinVar, OMIM, PubMed, ClinGen
Expressivity (variable, consistent) > Search first: OMIM, ClinVar, PubMed
Genetic anticipation (increasing severity in successive generations) > Search first: OMIM, PubMed (especially for repeat expansion disorders)
Germline mosaicism > Search first: ClinVar, OMIM, genetic counseling literature, PubMed
Founder effects (population-specific mutations) > Search first: gnomAD, population genetics databases, PubMed
Consanguinity role > Search first: OMIM, population studies, genetic counseling resources
Carrier frequency > Search first: gnomAD, carrier screening databases, GeneReviews, GTR
Population Demographics:
Affected populations (ethnic or demographic groups with higher prevalence) > Search first: gnomAD, 1000 Genomes, PAGE Study, PubMed, population registries
Geographic distribution (endemic areas, regional variation) > Search first: WHO, CDC, GBD, Orphanet, geographic epidemiology databases
Geographic distribution of specific variants
Sex ratio (male:female) > Search first: Disease registries, OMIM, PubMed, epidemiological databases
Age distribution of affected individuals > Search first: CDC, disease registries, SEER, Orphanet

10. Diagnostics

Clinical Tests:
Laboratory tests (blood, urine, tissue chemistry, specific enzyme assays) > Search first: LOINC, LabTests Online, PubMed
Biomarkers (proteins, metabolites, genetic markers, circulating biomarkers) > Search first: FDA Biomarker List, BEST (Biomarkers, EndpointS, and other Tools), PubMed
Imaging studies (X-ray, CT, MRI, PET, ultrasound) > Search first: RadLex, DICOM, Radiopaedia, imaging databases
Functional tests (pulmonary function, cardiac stress tests) > Search first: LOINC, clinical guidelines, PubMed
Electrophysiology (EEG, EMG, ECG, nerve conduction studies) > Search first: LOINC, clinical neurophysiology databases, PubMed
Biopsy findings (histopathology, immunohistochemistry) > Search first: SNOMED CT, College of American Pathologists resources, PubMed
Pathology findings (microscopic examination) > Search first: SNOMED CT, Digital Pathology databases, PubMed
Genetic Testing:

Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen
Overview of recommended genetic testing approach
Whole genome sequencing (WGS) utility > Search first: GTR, ClinVar, GEL (Genomics England), gnomAD
Whole exome sequencing (WES) utility > Search first: GTR, ClinVar, OMIM, GeneMatcher
Gene panels (which panels, which genes) > Search first: GTR, ClinVar, laboratory-specific databases
Single gene testing > Search first: GTR, ClinVar, OMIM, GeneReviews
Chromosomal microarray (CMA) > Search first: DECIPHER, ClinVar, dbVar, ECARUCA
Karyotyping > Search first: Chromosome Abnormality Database, ClinVar, cytogenetics resources
FISH > Search first: ClinVar, cytogenetics databases, PubMed
Mitochondrial DNA testing > Search first: MITOMAP, MSeqDR, ClinVar, GTR
Repeat expansion testing > Search first: GTR, ClinVar, repeat expansion databases, PubMed
Omics-Based Diagnostics (if applicable):
RNA sequencing / transcriptomics > Search first: GEO, ArrayExpress, GTEx, RNA-seq databases
Proteomics > Search first: PRIDE, ProteomeXchange, FDA Biomarker database
Metabolomics > Search first: MetaboLights, Metabolomics Workbench, HMDB
Epigenomics > Search first: GEO, ENCODE, Roadmap Epigenomics, MethBase
Liquid biopsy > Search first: COSMIC, ClinVar, liquid biopsy databases, PubMed
Clinical Criteria:
Standardized diagnostic criteria (DSM, ICD, society guidelines) > Search first: DSM-5, ICD-11, clinical society guidelines, UpToDate
Differential diagnosis (other conditions to rule out, with distinguishing features) > Search first: DynaMed, UpToDate, clinical decision support systems
Screening:
Screening methods for asymptomatic individuals (newborn screening, carrier screening, cascade screening) > Search first: ACMG recommendations, CDC newborn screening, GTR

11. Outcome/Prognosis

Survival and Mortality:
Survival rate (5-year, 10-year, overall) > Search first: SEER, cancer registries, disease-specific registries, PubMed
Life expectancy (with and without treatment if applicable) > Search first: Orphanet, disease registries, actuarial databases, PubMed
Mortality rate > Search first: CDC, WHO, GBD, national mortality databases
Disease-specific mortality (deaths directly attributable to disease) > Search first: Disease registries, CDC Wonder, GBD, PubMed
Morbidity and Function:
Morbidity (disease-related disability and health impacts) > Search first: GBD, WHO, disability databases, PubMed
Disability outcomes (long-term functional impairments) > Search first: ICF (International Classification of Functioning), disability registries
Quality of life measures (EQ-5D, SF-36, PROMIS, disease-specific tools) > Search first: EQ-5D database, SF-36, PROMIS, PubMed
Disease Course:
Complications (secondary problems: infections, organ failure, etc.) > Search first: ICD codes, disease registries, clinical databases, PubMed
Recovery potential (likelihood and extent of recovery, with vs without treatment) > Search first: Natural history studies, rehabilitation databases, PubMed
Prediction:
Prognostic factors (age, disease severity, biomarkers, treatment response) > Search first: Prognostic models databases, clinical calculators, PubMed
Prognostic biomarkers (molecular markers predicting disease course) > Search first: FDA Biomarker database, PubMed, cancer prognostic databases

12. Treatment

Pharmacotherapy:
Pharmacological treatments (drug names, drug classes, mechanisms of action) > Search first: DrugBank, RxNorm, ATC classification, DailyMed, FDA databases
Pharmacogenomics (how genetic variants affect drug metabolism, efficacy, toxicity) > Search first: PharmGKB, CPIC (Clinical Pharmacogenetics), FDA Table of PGx Biomarkers
Advanced Therapeutics:
Gene therapy (viral vectors, CRISPR, gene replacement, gene editing) > Search first: ClinicalTrials.gov, FDA gene therapy database, ASGCT resources
Cell therapy (stem cell transplant, CAR-T, cellular therapeutics) > Search first: ClinicalTrials.gov, FDA cell therapy database, FACT standards
RNA-based therapies (ASOs, siRNA, mRNA therapies) > Search first: ClinicalTrials.gov, FDA approvals, PubMed
Targeted therapies (treatments directed at specific molecular targets) > Search first: My Cancer Genome, OncoKB, ClinicalTrials.gov, FDA approvals
Immunotherapies (checkpoint inhibitors, monoclonal antibodies) > Search first: Cancer Immunotherapy Database, FDA approvals, ClinicalTrials.gov
Surgical and Interventional:
Surgical interventions (types of surgery, timing, outcomes) > Search first: CPT codes, surgical registries, clinical guidelines, PubMed
Supportive and Rehabilitative:
Supportive care (symptom management, pain control, nutrition) > Search first: Clinical guidelines, Cochrane Library, PubMed
Rehabilitation (physical therapy, occupational therapy, speech therapy) > Search first: Rehabilitation medicine databases, clinical guidelines, PubMed
Experimental:
Experimental treatments in clinical trials (with NCT identifiers if available) > Search first: ClinicalTrials.gov, EU Clinical Trials Register, WHO ICTRP
Treatment Outcomes:
Treatment response rates > Search first: Clinical trial databases, FDA reviews, systematic reviews, PubMed
Side effects and adverse events > Search first: FDA Adverse Event Reporting System (FAERS), MedWatch, PubMed
Treatment Strategy:
Treatment algorithms (clinical pathways, decision trees) > Search first: Clinical practice guidelines, NCCN Guidelines, UpToDate
Combination therapies > Search first: ClinicalTrials.gov, treatment guidelines, PubMed
Personalized medicine approaches (genotype-guided treatment) > Search first: My Cancer Genome, CIViC, PharmGKB, precision medicine databases

For each treatment, suggest NCIT (NCI Thesaurus) clinical-intervention terms where applicable.

13. Prevention

Prevention Levels:
Primary prevention (preventing disease occurrence: vaccination, risk factor modification) > Search first: CDC, WHO, USPSTF recommendations, Cochrane Library
Secondary prevention (early detection and treatment: screening programs, early intervention) > Search first: USPSTF, CDC screening guidelines, WHO
Tertiary prevention (preventing complications in those with disease) > Search first: Clinical guidelines, disease management protocols, PubMed
Immunization: Vaccine strategies (if applicable)

Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database
Screening and Early Detection:
Screening programs (population-based: newborn screening, cancer screening) > Search first: CDC screening programs, USPSTF, cancer screening databases
Genetic screening (carrier screening, preimplantation genetic diagnosis, prenatal testing) > Search first: ACMG recommendations, ACOG guidelines, GTR
Risk stratification (identifying high-risk individuals for targeted prevention) > Search first: Risk prediction models, clinical calculators, PubMed
Behavioral Interventions: Lifestyle modifications to reduce risk

Search first: CDC, WHO, behavioral intervention databases, Cochrane Library
Counseling: Genetic counseling (risk assessment, family planning guidance)

Search first: NSGC resources, ACMG guidelines, GeneReviews
Public Health:
Public health interventions (sanitation, vector control, health education) > Search first: CDC, WHO, public health databases, PubMed
Environmental interventions (reducing environmental risk factors) > Search first: EPA databases, WHO environmental health, PubMed
Prophylaxis: Preventive medications or procedures

Search first: Clinical guidelines, FDA approvals, PubMed

14. Other Species / Natural Disease

Taxonomy: Species affected (with NCBI Taxon identifiers)

Search first: NCBI Taxonomy
Breed: Specific breeds affected (with VBO identifiers if applicable)

Search first: VBO (Vertebrate Breed Ontology)
Gene: Orthologous genes in other species (with NCBI Gene IDs)

Search first: NCBI Gene
Natural Disease:
Naturally occurring disease in other species (companion animals, wildlife) > Search first: OMIA (Online Mendelian Inheritance in Animals), VetCompass, PubMed
Veterinary relevance and importance in animal health > Search first: OMIA, veterinary databases, PubMed
Comparative Biology:
Comparative pathology (similarities and differences across species) > Search first: OMIA, comparative pathology databases, PubMed
Evolutionary conservation of disease mechanisms > Search first: HomoloGene, OrthoMCL, Alliance of Genome Resources
Transmission (if applicable):
Zoonotic potential > Search first: CDC zoonotic diseases, WHO zoonoses, GIDEON
Cross-species susceptibility > Search first: NCBI Taxonomy, veterinary databases, PubMed

15. Model Organisms

Model Types:
Model organism type (mammalian, invertebrate, cellular, in vitro) > Search first: Alliance of Genome Resources, model organism databases
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Citation Requirements

Cite primary literature (PMID preferred) for all mechanistic and clinical claims
Prioritize recent reviews and landmark papers
Include direct quotes from abstracts where possible to support key statements
Distinguish evidence source types: human clinical, model organism, in vitro, computational

Output Format

Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, NCIT, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease

This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (NCIT terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details

Congenital Heart Defects and Skeletal Malformations Syndrome (CHDSKM)

Executive summary

Congenital heart defects and skeletal malformations syndrome is an ultra-rare, congenital, autosomal-dominant developmental disorder caused by heterozygous gain-of-function missense variants in ABL1. The cardinal phenotype comprises congenital heart disease, digital/skeletal abnormalities, characteristic facial dysmorphism, prenatal or postnatal growth impairment, and variably developmental delay, microcephaly, palatal anomalies, and hearing loss. It is mechanistically distinct from BCR::ABL1-positive leukemia and from recently described biallelic loss-of-function ABL1 deficiency. The evidence base remains small—approximately 18 aggregated individuals by the principal 2021 series—so frequencies, penetrance, prognosis, and management recommendations are provisional. (wang2017germlinemutationsin pages 3-3, blakes2021pathogenicvariantscausing pages 3-4)

The foundational paper reported that “ABL1 germline variants [co-segregate] with an autosomal dominant disorder characterized by congenital heart disease, skeletal abnormalities, and failure to thrive.” It identified recurrent p.Tyr245Cys and de novo p.Ala356Thr and showed increased tyrosine phosphorylation in transfected cells. [Wang et al., Nature Genetics, published March 2017; PMID: 28288113; DOI: 10.1038/ng.3815; https://doi.org/10.1038/ng.3815]. (wang2017germlinemutationsin pages 3-3, wang2017germlinemutationsin pages 1-2)

A useful evidence synopsis is provided below.

Domain	Best-supported finding	Quantitative evidence	Evidence type/source
Disease identifiers	ABL1-related congenital heart defects and skeletal malformations syndrome is a Mendelian developmental disorder linked to MONDO:0060532 and ABL1; Open Targets shows a single strong disease-target association for ABL1.	Open Targets association score 0.8012; evidence count 5 tied to the foundational literature.	Curated disease-target resource and literature linkage (Open Targets context) (OpenTargets Search: congenital heart defects and skeletal malformations syndrome-ABL1)
Core definition	Foundational human evidence established that germline ABL1 variants cause an autosomal dominant syndrome characterized by congenital heart defects, skeletal abnormalities/malformations, dysmorphic features, and failure to thrive.	Initial report: 6 affected individuals from 4 families.	Human clinical genetics, Nature Genetics 2017, doi:10.1038/ng.3815 (PMID linked in Open Targets as 28288113) (wang2017germlinemutationsin pages 3-3, wang2017germlinemutationsin pages 1-2)
Inheritance	CHDSKM shows autosomal dominant inheritance with both de novo occurrence and vertical transmission/cosegregation in families.	2017 series: p.Tyr245Cys occurred de novo or cosegregated in families 1-3; p.Ala356Thr was de novo in family 4. 2021 series: 5/6 new cases had de novo confirmation.	Human clinical genetics, Nature Genetics 2017 doi:10.1038/ng.3815; Eur J Hum Genet 2021 doi:10.1038/s41431-020-00766-w (wang2017germlinemutationsin pages 3-3, blakes2021pathogenicvariantscausing pages 6-8)
Molecular mechanism class	The disorder is best supported as an ABL1 gain-of-function kinase syndrome, not haploinsufficiency. Mutant proteins show increased tyrosine phosphorylation/kinase activity.	Increased phosphorylation of ABL1-specific substrates in HEK293T/HEK 293T assays for p.Tyr245Cys, p.Ala356Thr, and additional 2021 variants; 2024 biochemical work shows E528K vmax ~202 vs WT ~89 (>2-fold), with KM unchanged.	Human variant functional assays and biochemical/structural studies, 2017/2021/2024 (doi:10.1038/ng.3815; doi:10.1038/s41431-020-00766-w; doi:10.1101/2023.10.04.560671) (blakes2021pathogenicvariantscausing pages 1-2, wang2017germlinemutationsin pages 3-4, paladini2024themolecularbasis pages 9-10, paladini2024themolecularbasis pages 6-9)
Variant spectrum	Reported pathogenic CHDSKM missense variants include p.Tyr245Cys, p.Val244Ala, p.Ala356Thr, p.Ala452Thr, p.Val525Ala, p.Glu528Lys. Several cluster in/near the kinase regulatory myristoyl-binding pocket.	2017: 2 variants (c.734A>G p.Tyr245Cys, c.1066G>A p.Ala356Thr). 2021: total 5 germline variants listed as c.731T>C p.Val244Ala, c.1066G>A p.Ala356Thr, c.1354G>A p.Ala452Thr, c.1574T>C p.Val525Ala, c.1582G>A p.Glu528Lys.	Human clinical/variant interpretation studies, 2017 and 2021 (wang2017germlinemutationsin pages 3-3, blakes2021pathogenicvariantscausing pages 5-6)
Variant: Tyr245Cys	p.Tyr245Cys is a recurrent causal variant in the SH2-kinase linker region associated with CHDSKM and increased kinase signaling.	Seen in 5 individuals across families 1-3 in the 2017 report; absent from dbSNP/ESP/ExAC/COSMIC in that study.	Human clinical genetics plus in vitro functional assay, Nature Genetics 2017 doi:10.1038/ng.3815 (PMID 28288113 via Open Targets) (wang2017germlinemutationsin pages 3-3, wang2017germlinemutationsin pages 3-4)
Variant: Val244Ala	p.Val244Ala is a de novo CHDSKM variant affecting the SH2-kinase linker/regulatory region and functionally increases ABL1 signaling.	Reported among the 6 new unrelated individuals in 2021; described as de novo; functional assays showed increased STAT5B/overall tyrosine phosphorylation.	Human case series with in vitro functional validation, Eur J Hum Genet 2021 doi:10.1038/s41431-020-00766-w (blakes2021pathogenicvariantscausing pages 8-9, blakes2021pathogenicvariantscausing pages 6-8)
Variant: Ala356Thr	p.Ala356Thr is a de novo kinase-domain CHDSKM variant with increased kinase activity.	Present in 1 individual in 2017 and also represented in 2021 aggregated variant list; increased phosphotyrosine and STAT5 phosphorylation in vitro.	Human clinical genetics and in vitro assay, 2017/2021 (wang2017germlinemutationsin pages 3-3, blakes2021pathogenicvariantscausing pages 5-6, blakes2021pathogenicvariantscausing pages 4-5)
Variant: Ala452Thr	p.Ala452Thr is a CHDSKM-associated kinase-domain variant included in the expanded 2021 spectrum.	Listed among pathogenic/likely pathogenic variants in 2021; individual table excerpt notes growth, craniofacial, and cardiac findings in affected patient(s).	Human case series, Eur J Hum Genet 2021 doi:10.1038/s41431-020-00766-w (blakes2021pathogenicvariantscausing pages 5-6, blakes2021pathogenicvariantscausing pages 4-5)
Variant: Val525Ala	p.Val525Ala is a de novo variant in the myristoyl-binding pocket/kinase domain supporting the autoinhibition-loss model.	Included in 2021 five-variant set; one of the variants clustering in the myristoyl pocket.	Human case series with structural interpretation and kinase assay, Eur J Hum Genet 2021 doi:10.1038/s41431-020-00766-w (blakes2021pathogenicvariantscausing pages 8-9, blakes2021pathogenicvariantscausing pages 5-6)
Variant: Glu528Lys	p.Glu528Lys (E528K) is a de novo myristoyl-pocket/αI'-helix variant strongly linked to gain-of-function and later structural definition.	Included in 2021 case series as de novo; 2024 study shows disruption of the E528-R479 salt bridge, increased core disassembly, and >2-fold activity increase.	Human case series + biochemical/structural mechanism, 2021/2024 (blakes2021pathogenicvariantscausing pages 8-9, paladini2024themolecularbasis pages 9-10, paladini2024themolecularbasis pages 11-12, paladini2024themolecularbasis pages 10-11)
Population frequency	Reported CHDSKM variants are extremely rare; the expanded 2021 series states all listed pathogenic variants were absent from gnomAD.	5/5 listed 2021 variants absent from gnomAD; 2017 variants absent from dbSNP, ESP, ExAC, COSMIC.	Human variant interpretation, 2017 and 2021 (blakes2021pathogenicvariantscausing pages 5-6, wang2017germlinemutationsin pages 3-4)
Aggregated phenotype burden	Across the 18 reported cases summarized in 2021, the most frequent findings were dysmorphic facies, digital anomalies, congenital heart disease, failure to thrive, developmental delay, IUGR, ear abnormalities, palatal deformity, and microcephaly.	Dysmorphic facies 18/18 (100%); finger/toe abnormalities 17/18 (94%); congenital heart disease 14/18 (78%); failure to thrive 14/18 (78%); developmental delay 11/18 (61%); IUGR 10/18 (56%); ear abnormalities 9/18 (50%); palatal deformity 9/18 (50%); microcephaly 9/18 (50%).	Aggregated human case series, Eur J Hum Genet 2021 doi:10.1038/s41431-020-00766-w (blakes2021pathogenicvariantscausing pages 3-4)
Cardiac phenotype	Cardiac disease is a cardinal manifestation; specific reported defects include septal defects, patent ductus arteriosus, supravalvular pulmonary stenosis, and aortic root dilatation.	CHD in 6/6 initial 2017 patients and 14/18 pooled cases by 2021.	Human clinical case reports/series, 2017 and 2021 (wang2017germlinemutationsin pages 1-2, blakes2021pathogenicvariantscausing pages 8-9, blakes2021pathogenicvariantscausing pages 2-3, blakes2021pathogenicvariantscausing pages 4-5)
Skeletal/limb phenotype	Skeletal/digital anomalies are pervasive and include scoliosis, pectus excavatum, hindfoot deformity, finger contractures, camptodactyly, clinodactyly, Dupuytren contracture, and toe syndactyly.	Skeletal abnormalities in 6/6 initial 2017 cohort; finger/toe abnormalities 17/18 pooled; camptodactyly noted in 5/6 in one excerpt from the 2021 cohort.	Human clinical case series, 2017/2021 (wang2017germlinemutationsin pages 1-2, blakes2021pathogenicvariantscausing pages 5-6, blakes2021pathogenicvariantscausing pages 2-3)
Hearing	Hearing impairment appears to be a recurrent feature in the expanded syndrome.	2021 cohort excerpt: hearing impairment 4/6 in the new series; authors state hearing impairment is a common feature.	Human clinical case series, Eur J Hum Genet 2021 doi:10.1038/s41431-020-00766-w (blakes2021pathogenicvariantscausing pages 1-2, blakes2021pathogenicvariantscausing pages 2-3, blakes2021pathogenicvariantscausing pages 5-6)
Growth/development	Growth restriction and neurodevelopmental issues are common but variable.	Failure to thrive 14/18; IUGR 10/18; developmental delay 11/18. 2017 series also reported failure to thrive in 5/6.	Human clinical case series, 2017/2021 (wang2017germlinemutationsin pages 1-2, blakes2021pathogenicvariantscausing pages 3-4)
Other organ involvement	Additional reported manifestations include male genital anomalies, GI anomalies, renal hypoplasia, ocular abnormalities, and occasional other malformations.	2017: hypospadias/hypogonadism 3/4 males, pyloric muscle thickening 1/6, imperforate anus 1/6. 2021 abstract notes renal hypoplasia and ocular abnormalities in affected individuals.	Human clinical reports, 2017/2021 (wang2017germlinemutationsin pages 3-3, blakes2021pathogenicvariantscausing pages 1-2)
2024 structural mechanism	The best current mechanistic explanation for E528K is disruption of the E528-R479 salt bridge at the end of the αI'-helix, increasing force on the SH2 domain, disassembling the SH3-SH2-kinase regulatory core, and activating kinase function.	2024 study reports Pearson correlation between activity and imatinib-induced disassembly r=0.89; vmax ~202 vs ~89 for WT, KM unchanged.	Biochemical/structural study, eLife 2024/preprint DOI 10.1101/2023.10.04.560671 (paladini2024themolecularbasis pages 9-10, paladini2024themolecularbasis pages 11-12, paladini2024themolecularbasis pages 10-11, paladini2024themolecularbasis pages 1-2)
Pharmacologic implication	In vitro, mutant hyperphosphorylation can be suppressed by imatinib; 2024 work also supports opposing effects of type II ATP-site inhibitors versus allosteric stabilization of the myristoyl pocket/αI-helix.	2021: imatinib abolished phosphorylation across constructs. 2024: asciminib reduces activity by fixating the αI-helix, whereas type II inhibitors like imatinib promote core disassembly despite ATP-site inhibition.	Functional/structural pharmacology, 2021 and 2024 (blakes2021pathogenicvariantscausing pages 1-2, blakes2021pathogenicvariantscausing pages 6-8, paladini2024themolecularbasis pages 1-2)
Diagnosis	Diagnosis has been established primarily by clinical exome sequencing / whole exome sequencing in individuals with syndromic CHD plus skeletal/dysmorphic features, followed by variant interpretation and, in research settings, functional testing.	2017 and 2021 causal discoveries both relied on exome-based approaches; one 2022 ES study cited CHDSKM as a diagnosable syndromic entity in broader congenital anomaly testing.	Human diagnostic genomics studies, 2017/2021/2022 (wang2017germlinemutationsin pages 1-2, blakes2021pathogenicvariantscausing pages 1-2)
Management considerations	Published management suggestions are supportive and surveillance-based: assess congenital heart disease, consider aortic root diameter screening, and obtain audiology assessment because aortopathy/hearing issues recur.	Explicit 2021 recommendations mention aortic root diameter screening at diagnosis and audiological assessment; no disease-specific treatment outcomes reported.	Expert interpretation within human case series, Eur J Hum Genet 2021 doi:10.1038/s41431-020-00766-w (blakes2021pathogenicvariantscausing pages 8-9)
Malignancy risk	Despite ABL1’s oncologic relevance, no hematologic malignancy was reported in available CHDSKM cases, though long-term surveillance has been suggested because evidence is sparse.	Reported CHDSKM cases with malignancy: 0 in available excerpts.	Human case series commentary, 2017/2021 (blakes2021pathogenicvariantscausing pages 8-9, wang2017germlinemutationsin pages 3-4)
Distinction from ABL1 deficiency	CHDSKM is not equivalent to biallelic ABL1 loss/deficiency. Available evidence supports constitutional gain-of-function in CHDSKM, while separate literature notes biallelic loss-of-function ABL1 deficiency is phenotypically distinct.	Distinction stated explicitly in 2023 diagnostic-pitfall literature; mouse Abl1 knockout phenotypes (growth delay, cardiac hyperplasia, osteoporosis, lymphopenia, eye/head defects, perinatal lethality) differ from the human GOF syndrome.	Human genetics commentary plus model-organism evidence (wang2017germlinemutationsin pages 3-3, blakes2021pathogenicvariantscausing pages 2-3)
Evidence gaps	Major gaps remain: ultra-rare disease frequency/prevalence unknown; no validated biomarkers or formal diagnostic criteria; no disease-specific clinical trials; no robust natural-history, survival, QoL, penetrance, or genotype-response datasets.	Published evidence is based on roughly 18 aggregated human cases by 2021 plus mechanistic follow-up; no interventional CHDSKM trial evidence was retrieved.	Synthesis of available human case series and lack of retrieved disease-specific trials (blakes2021pathogenicvariantscausing pages 3-4)

Table: This table condenses the strongest currently retrieved evidence for ABL1-related congenital heart defects and skeletal malformations syndrome, including identifiers, inheritance, variant spectrum, pooled phenotype frequencies, mechanism, and management implications. It is useful as a curation-ready summary that also flags where evidence remains sparse or absent.

1. Disease information

Definition and identifiers

Preferred name: Congenital heart defects and skeletal malformations syndrome.
Common alternatives: ABL1-related congenital heart defects and skeletal malformations syndrome; ABL1-related malformation syndrome; ABL1 malformation syndrome; CHDSKM.
MONDO: MONDO:0060532.
OMIM phenotype: 617602.
Causal gene: ABL1, HGNC:76; Ensembl ENSG00000097007; protein name, ABL proto-oncogene 1, non-receptor tyrosine kinase.
Gene–disease validity: Open Targets links MONDO:0060532 only to ABL1, with five evidence records ultimately anchored to PMID 28288113. (OpenTargets Search: congenital heart defects and skeletal malformations syndrome-ABL1)
Orphanet, MeSH, ICD-10/ICD-11: No disease-specific identifier was established in the retrieved authoritative evidence. In clinical coding, component anomalies are therefore likely coded separately; a syndrome-specific ICD code should not be inferred.

This entry is based on aggregated disease-level resources and published patient cohorts, not an individual EHR. Nevertheless, almost all phenotype estimates originate from a small number of individually described patients and are vulnerable to ascertainment and publication bias.

Scope exclusions

CHDSKM is not Holt–Oram syndrome/TBX5 disorder, Ellis–van Creveld syndrome, VACTERL association, Char syndrome, or a BCR::ABL1-positive hematologic neoplasm. It is also not “human ABL1 deficiency syndrome,” which results from biallelic loss-of-function alleles and represents a different allelic disorder. (wang2017germlinemutationsin pages 3-3)

2. Etiology, risk, and protective factors

Primary cause

The established cause is a constitutional, heterozygous ABL1 missense variant that increases kinase activity. Reported disease alleles affect the SH2–kinase linker or regulatory kinase/myristoyl-pocket region, impairing normal autoinhibition. Both de novo occurrence and vertical transmission have been documented. (wang2017germlinemutationsin pages 3-3, blakes2021pathogenicvariantscausing pages 5-6, blakes2021pathogenicvariantscausing pages 6-8)

Genetic risk factors

Supported variants include:

NM_005157.6:c.731T>C, p.Val244Ala;
c.734A>G, p.Tyr245Cys;
c.1066G>A, p.Ala356Thr;
c.1354G>A, p.Ala452Thr;
c.1574T>C, p.Val525Ala;
c.1582G>A, p.Glu528Lys. (wang2017germlinemutationsin pages 3-3, blakes2021pathogenicvariantscausing pages 5-6)

The recurrent p.Tyr245Cys allele occurred de novo or segregated with disease in five individuals from three families; p.Ala356Thr was de novo in the sixth original patient. Five of six newly reported individuals in 2021 had confirmed de novo variants. The studied alleles were absent from gnomAD, and the original alleles were absent from dbSNP, ESP, ExAC, and COSMIC at publication. (wang2017germlinemutationsin pages 3-3, wang2017germlinemutationsin pages 3-4, blakes2021pathogenicvariantscausing pages 6-8)

Environmental, infectious, lifestyle, and protective factors

No environmental exposure, infection, diet, behavior, occupational factor, sex-specific exposure, protective allele, or validated modifier has been shown to cause or prevent CHDSKM. Because malformations originate during embryogenesis from a high-effect germline allele, generic congenital-heart risk factors should not be entered as CHDSKM-specific causes. No demonstrated gene–environment interaction is available.

The developmental abnormalities reported after fetal exposure to BCR–ABL inhibitors provide biological support that tightly regulated ABL activity matters in embryogenesis, but drug exposure is not evidence of the etiology of inherited CHDSKM. (wang2017germlinemutationsin pages 3-3)

3. Phenotypes

Pooled phenotype frequencies

Among 18 individuals summarized in 2021:

dysmorphic facies: 18/18 (100%);
finger/toe abnormalities: 17/18 (94%);
congenital heart disease: 14/18 (78%);
failure to thrive: 14/18 (78%);
developmental delay: 11/18 (61%);
intrauterine growth restriction: 10/18 (56%);
ear abnormalities: 9/18 (50%);
palatal deformity: 9/18 (50%);
microcephaly: 9/18 (50%). (blakes2021pathogenicvariantscausing pages 3-4)

These figures are descriptive case-series proportions, not population penetrance estimates.

Cardiovascular

Reported manifestations include septal defects, patent ductus arteriosus, supravalvular pulmonary stenosis, and aortic-root dilatation. CHD was present in all six original patients and 14/18 pooled cases. Aortic dilatation may be progressive and warrants longitudinal measurement, whereas repaired structural defects may remain stable after intervention. Suggested terms include HP:0001627 Congenital heart defect, ventricular/atrial septal defect terms, patent ductus arteriosus, pulmonary stenosis, and aortic-root dilatation. (wang2017germlinemutationsin pages 1-2, blakes2021pathogenicvariantscausing pages 8-9, blakes2021pathogenicvariantscausing pages 4-5)

Skeletal, limb, and connective-tissue manifestations

The spectrum includes scoliosis, pectus excavatum, hindfoot deformity, finger contractures, camptodactyly, clinodactyly, Dupuytren-type contracture, toe syndactyly, and occasionally scaphocephaly. Finger/toe abnormalities occurred in 17/18 pooled cases; camptodactyly was reported in 5/6 of the expanded cohort, and scoliosis in 3/6 of the original cohort. Suggested terms include HP:0000924 Abnormality of the skeletal system, camptodactyly, clinodactyly, syndactyly, scoliosis, pectus excavatum, and joint contracture. (wang2017germlinemutationsin pages 1-2, wang2017germlinemutationsin pages 3-3, blakes2021pathogenicvariantscausing pages 2-3, blakes2021pathogenicvariantscausing pages 5-6)

Craniofacial, oral, hearing, growth, and neurologic features

Facial findings include an elongated/narrow face, long narrow nose, deep-set eyes, high-arched eyebrows, microretrognathia or small chin, thin lips, and downturned mouth. Palatal findings include a high-arched or otherwise abnormal palate and dental crowding. Suggested HPO terms include facial dysmorphism, HP:0000347 Micrognathia, high-arched palate, and dental crowding. (blakes2021pathogenicvariantscausing pages 5-6, blakes2021pathogenicvariantscausing pages 4-5)

Hearing impairment was present in 4/6 newly reported patients and may be conductive or mixed. Baseline and serial audiology are therefore reasonable. Suggested term: HP:0000365 Hearing impairment, refined to conductive or mixed hearing loss when documented. (blakes2021pathogenicvariantscausing pages 1-2, blakes2021pathogenicvariantscausing pages 2-3)

Growth manifestations begin prenatally or in infancy and include IUGR, failure to thrive, and variable short stature. Neurodevelopmental involvement ranges from apparently normal development to developmental delay; microcephaly occurred in 9/18. Suggested terms include HP:0001511 Intrauterine growth retardation, HP:0001508 Failure to thrive, HP:0000252 Microcephaly, and HP:0001263 Global developmental delay. (blakes2021pathogenicvariantscausing pages 3-4, blakes2021pathogenicvariantscausing pages 4-5)

Other organ systems

Male genital abnormalities—hypospadias or hypogonadism—occurred in 3/4 males in the original cohort. Pyloric muscle thickening and imperforate anus each occurred in one of six. Renal hypoplasia and ocular abnormalities have also been reported, but frequencies are not robust. Suggested HPO concepts include hypospadias, hypogonadism, pyloric stenosis/thickening, imperforate anus, renal hypoplasia, and the specific ocular abnormality observed. (wang2017germlinemutationsin pages 3-3, blakes2021pathogenicvariantscausing pages 1-2)

Quality of life

No CHDSKM-specific EQ-5D, SF-36, PROMIS, functional-status, or caregiver-burden study was found. Likely burdens arise from cardiac procedures and surveillance, feeding/growth problems, hearing impairment, developmental support needs, and orthopedic limitations, but quantitative disease-specific effects are unavailable.

4. Genetic and molecular information

Gene and variant class

ABL1 encodes a ubiquitously expressed non-receptor tyrosine kinase. CHDSKM variants are germline, heterozygous missense alleles. Available functional evidence supports gain of function through loss of autoinhibition, not haploinsufficiency or a dominant-negative effect. The 2021 alleles were classified as pathogenic or likely pathogenic under ACMG/AMP reasoning and were absent from gnomAD. (blakes2021pathogenicvariantscausing pages 1-2, blakes2021pathogenicvariantscausing pages 5-6)

The 2017 abstract states: “We overexpressed the mutant constructs in HEK 293T cells and observed increased tyrosine phosphorylation, suggesting increased ABL1 kinase activities associated with both the p.Tyr245Cys and p.Ala356Thr substitutions.” (wang2017germlinemutationsin pages 3-3, wang2017germlinemutationsin pages 3-4)

Allelic disorders and cancer distinction

CHDSKM germline GOF alleles should not be conflated with the acquired BCR::ABL1 fusion, which drives chronic myeloid and other leukemias. No hematologic malignancy was reported in the available CHDSKM patients, although follow-up is too short and the cohort too small to establish lifetime risk. Biallelic ABL1 loss-of-function causes a separate deficiency syndrome and should not be merged with CHDSKM. (blakes2021pathogenicvariantscausing pages 8-9, wang2017germlinemutationsin pages 3-4, wang2017germlinemutationsin pages 3-3)

Modifiers, epigenetics, and chromosome abnormalities

No validated modifier gene, syndrome-specific methylation signature, histone alteration, chromatin biomarker, recurrent copy-number variant, translocation, inversion, or aneuploidy is known. The causal lesions reported for CHDSKM are sequence-level ABL1 missense variants.

5. Environmental information

No toxin, radiation source, pollution exposure, maternal lifestyle factor, nutritional deficit, infection, or immune trigger has been established. CHDSKM is neither infectious nor transmissible. Environmental information should therefore be recorded as not established, rather than “absent,” because the cohort is too small for formal interaction studies.

6. Mechanism and pathophysiology

Causal chain

A germline missense substitution affects the SH2–kinase linker, kinase domain, or myristoyl-binding/αI-helix regulatory region.
The substitution weakens intramolecular autoinhibition and favors disassembly of the SH3–SH2–kinase regulatory core.
ABL1 kinase activity and phosphorylation of downstream substrates, including STAT5B in experimental assays, increase.
Dysregulated signaling during embryonic cardiac, craniofacial, skeletal, growth, auditory, and other organ development produces congenital malformations and postnatal growth/developmental consequences. Steps 1–3 are experimentally supported; the precise lineage-specific route from kinase hyperactivity to each human malformation remains unresolved. (blakes2021pathogenicvariantscausing pages 1-2, blakes2021pathogenicvariantscausing pages 5-6, wang2017germlinemutationsin pages 3-4)

2024 structural advance: p.Glu528Lys

The most important recent mechanistic development is the structural/biochemical analysis of p.Glu528Lys. In wild-type ABL1, Glu528 at the end of the αI′ helix forms a salt bridge with Arg479 in the kinase-domain C-lobe, constraining αI′-helix motion and stabilizing the assembled, low-activity regulatory core. E528K breaks this bridge, increases force from the αI helix onto SH2, promotes SH3–SH2–kinase-core disassembly, and raises kinase activity. The mutant had a reported Vmax of approximately 202 versus 89 for wild type, with unchanged KM; kinase activity correlated with imatinib-induced core disassembly at r=0.89. [Paladini et al., eLife, January 2024; DOI landing page: https://doi.org/10.1101/2023.10.04.560671]. (paladini2024themolecularbasis pages 9-10, paladini2024themolecularbasis pages 11-12, paladini2024themolecularbasis pages 10-11, paladini2024themolecularbasis pages 6-9)

The paper’s abstract summarizes that E528K “strongly activates Abl by breaking a salt bridge with the KD C-lobe and thereby increasing the force onto the SH2 domain.” It also shows that the allosteric inhibitor asciminib stabilizes the αI helix and reduces this force, while type-II ATP-site inhibitors can promote regulatory-core opening even while inhibiting catalysis. This mechanistic complexity argues against simply translating leukemia dosing into children with a developmental syndrome. (paladini2024themolecularbasis pages 1-2)

Cellular and biochemical annotation

Suggested GO annotations include protein tyrosine kinase activity (GO:0004713), protein phosphorylation, signal transduction, regulation of cell adhesion and cytoskeletal organization, and developmental processes. Relevant cellular compartments include cytoplasm (GO:0005737), nucleus (GO:0005634), plasma-membrane-associated signaling complexes, and the ABL1 SH3–SH2–kinase regulatory core. STAT5B phosphorylation is an experimental readout, not a validated patient biomarker. (blakes2021pathogenicvariantscausing pages 5-6, wang2017germlinemutationsin pages 3-4)

No CHDSKM-specific metabolomic, lipidomic, proteomic, patient transcriptomic, epigenomic, spatial-transcriptomic, organoid, or single-cell dataset was established in the retrieved evidence. Candidate developmental cell types—cardiomyocytes, endocardial/valvular interstitial cells, cardiac neural-crest derivatives, chondrocytes/osteoblast-lineage cells, fibroblasts, and craniofacial mesenchyme—remain biologically plausible rather than directly demonstrated CHDSKM targets. Corresponding broad CL concepts may be used only as hypotheses, not asserted disease associations.

7. Anatomical structures affected

Primary organ systems are:

cardiovascular: cardiac septa, ductus arteriosus, pulmonary outflow tract/valve region, and aortic root;
musculoskeletal/connective tissue: axial skeleton, thoracic cage, hands, feet, joints, and tendons/fascia;
craniofacial/oral: skull, mandible, palate, dentition, and external ears;
auditory: middle/inner-ear pathways depending on hearing-loss type;
growth/neurodevelopment: head growth and central nervous system development;
secondary/variable: kidney, eye, pylorus, anorectum, and male genital tract. (wang2017germlinemutationsin pages 1-2, blakes2021pathogenicvariantscausing pages 8-9, wang2017germlinemutationsin pages 3-3, blakes2021pathogenicvariantscausing pages 1-2, blakes2021pathogenicvariantscausing pages 4-5)

Suggested UBERON concepts include heart, interventricular/interatrial septum, aortic root, pulmonary artery/valve, axial skeleton, hand, foot, palate, mandible, ear, kidney, eye, pylorus, anus, and male external genitalia. No consistent lateralization has been reported.

8. Temporal development and natural history

Onset is prenatal/congenital: IUGR and structural cardiac/skeletal malformations originate during embryofetal development. Failure to thrive, hearing impairment, developmental delay, microcephaly, scoliosis, contractures, and aortic-root enlargement may become more evident during childhood. (wang2017germlinemutationsin pages 1-2, blakes2021pathogenicvariantscausing pages 8-9, blakes2021pathogenicvariantscausing pages 3-4)

There is no validated staging system. Structural malformations are generally persistent unless surgically corrected; developmental and growth trajectories are variable; scoliosis, contractures, hearing loss, and aortic dimensions merit longitudinal monitoring. No remission pattern is applicable to the underlying germline disorder. The critical causal period is embryogenesis, while postnatal opportunities concern early cardiac correction, hearing intervention, nutrition, therapy, and surveillance.

9. Inheritance and population

Inheritance is autosomal dominant. Both de novo and inherited disease have been demonstrated, including paternal transmission and multigenerational cosegregation. Expressivity is variable. The small pedigrees suggest substantial penetrance for recognizable developmental abnormalities, but numerical penetrance cannot be estimated. There is no evidence of anticipation, a founder allele, population enrichment, consanguinity dependence, or a defined carrier frequency. (wang2017germlinemutationsin pages 3-3, wang2017germlinemutationsin pages 1-2, blakes2021pathogenicvariantscausing pages 6-8)

No prevalence, incidence, geographic distribution, ethnic enrichment, sex ratio, or population-based age distribution has been measured. The published denominator—approximately 18 aggregated cases by 2021—indicates extreme rarity but is not a prevalence estimate. (blakes2021pathogenicvariantscausing pages 3-4)

10. Diagnosis

Clinical recognition

Suspect CHDSKM in a patient with syndromic congenital heart disease plus digital/skeletal abnormalities, characteristic narrow facial appearance or micrognathia, growth restriction/failure to thrive, hearing impairment, palatal anomaly, or microcephaly. There are no consensus clinical diagnostic criteria or pathognomonic biochemical biomarkers.

Baseline clinical evaluation

Recommended phenotype-driven studies include:

echocardiography with explicit aortic-root dimensions; ECG as clinically indicated;
skeletal survey or targeted radiographs, spinal examination, and orthopedic assessment;
formal audiology;
growth, nutrition, developmental, and neurologic assessment;
renal ultrasound, ophthalmology, and GI/GU evaluation when indicated by examination;
consideration of routine blood counts during long-term follow-up, recognizing that cancer risk is unquantified. Aortic-root and audiologic screening were specifically recommended by the expanded case series. (blakes2021pathogenicvariantscausing pages 8-9)

Molecular testing

The preferred test is a congenital-heart/multiple-malformation panel that includes ABL1, trio exome sequencing, or trio genome sequencing. Exome sequencing identified the original and expanded cohorts. A positive result should establish phase and germline origin, include parental testing, and evaluate whether the missense allele falls in a known regulatory region and matches the GOF disease mechanism. (blakes2021pathogenicvariantscausing pages 1-2, wang2017germlinemutationsin pages 1-2)

Single-gene sequencing is reasonable when the phenotype is highly characteristic or a familial variant is known. Genome sequencing may detect noncoding or structural lesions missed by exome, but no CHDSKM-specific incremental yield is known. CMA is appropriate for multiple congenital anomalies when sequence testing is negative or CNV disease is suspected, but it does not reliably detect these single-nucleotide variants. Karyotype/FISH, mitochondrial testing, and repeat-expansion testing are not first-line CHDSKM assays.

A VUS should not establish diagnosis. Functional kinase/substrate-phosphorylation assays remain research tools rather than validated clinical tests.

Differential diagnosis

Important alternatives include Holt–Oram syndrome (TBX5; upper-limb radial-ray defects), Ellis–van Creveld syndrome (EVC/EVC2; short ribs, polydactyly, disproportionate short stature), Char syndrome (TFAP2B; PDA with characteristic facies and fifth-finger anomalies), VACTERL association, Kabuki syndrome, RASopathies, connective-tissue aortopathies, and chromosomal/CNV syndromes. Distinction requires detailed limb patterning, associated-organ phenotype, inheritance, and molecular testing. CHDSKM is especially supported by an appropriate heterozygous GOF-region ABL1 variant.

Screening

There is no population newborn or carrier-screening program. Cascade testing is indicated after a familial pathogenic variant is identified. Prenatal diagnosis by CVS/amniocentesis and preimplantation genetic testing for monogenic disease are technically possible for a known familial variant. Fetal echocardiography and detailed ultrasound assess manifestations but cannot exclude the disorder.

11. Outcome and prognosis

No 5- or 10-year survival rate, life-expectancy estimate, mortality rate, prognostic score, or validated prognostic biomarker is available. Prognosis is probably driven chiefly by the type and severity of congenital heart disease, aortic involvement, feeding/growth difficulties, hearing impairment, developmental needs, and orthopedic complications. This is an inference from the phenotype, not a measured outcome model.

No malignancy was reported in the available patients, but the absence of events in a very small, mostly young cohort does not prove normal lifetime cancer risk. Long-term registries should capture aortic dimensions, cardiovascular procedures, hearing trajectory, growth, neurodevelopment, mobility, malignancy, and patient-reported quality of life. (blakes2021pathogenicvariantscausing pages 8-9, wang2017germlinemutationsin pages 3-4)

12. Treatment

Current real-world management

There is no approved disease-modifying treatment. Care is individualized and multidisciplinary:

pediatric/adult congenital cardiology for defect-specific catheter or surgical management and serial aortic imaging;
orthopedics, physiotherapy, and occupational therapy for scoliosis, foot deformity, contractures, and hand function;
audiology, hearing aids, or ENT intervention as appropriate;
nutrition and gastroenterology for feeding difficulty/failure to thrive;
developmental pediatrics with physical, occupational, and speech/language therapy;
renal, ophthalmologic, GI, and urologic management according to manifestations.

Suggested NCIT intervention concepts include cardiac surgical procedure, echocardiography, hearing aid, physical therapy, occupational therapy, speech therapy, nutritional support, orthopedic surgery, and genetic counseling; exact NCIT identifiers should be resolved against the current NCIt release.

ABL inhibitors: experimental only

In HEK293T assays, imatinib suppressed increased mutant ABL1-substrate phosphorylation and abolished phosphorylation across tested constructs, demonstrating pharmacologic tractability. This is preclinical evidence, not proof of clinical benefit, dose, timing, or safety in CHDSKM. (blakes2021pathogenicvariantscausing pages 1-2, blakes2021pathogenicvariantscausing pages 6-8)

The 2024 structural work suggests that allosteric myristoyl-pocket inhibition by asciminib stabilizes the αI-helix, whereas type-II inhibitors such as imatinib have more complex effects on regulatory-core assembly. Moreover, inhibiting ABL during development may itself be teratogenic. Consequently, imatinib, asciminib, or other tyrosine-kinase inhibitors should not be considered routine CHDSKM treatment outside a rigorously justified research protocol. (wang2017germlinemutationsin pages 3-3, paladini2024themolecularbasis pages 1-2)

No CHDSKM-specific interventional trial or NCT identifier was found. Retrieved ABL1 inhibitor trials concerned BCR::ABL1-positive leukemia and are not applicable to this congenital syndrome.

13. Prevention

Primary prevention of a de novo pathogenic variant is not currently possible. For an affected heterozygous parent, each pregnancy has an expected 50% transmission probability, although severity cannot be predicted reliably because expressivity is variable. Genetic counseling, cascade testing, prenatal molecular diagnosis, fetal echocardiography, and PGT-M are the principal reproductive-risk interventions. (wang2017germlinemutationsin pages 3-3, wang2017germlinemutationsin pages 1-2)

Secondary prevention consists of early molecular diagnosis and prompt detection of cardiac, aortic, auditory, growth, and developmental involvement. Tertiary prevention includes timely repair of hemodynamically important defects, serial aortic surveillance, hearing support, nutritional intervention, rehabilitation, and orthopedic management. Vaccination, antimicrobial prophylaxis, or lifestyle modification does not prevent the genetic syndrome; ordinary congenital-heart guidelines may still govern immunization and procedure-specific endocarditis prophylaxis.

14. Other species and natural disease

No naturally occurring veterinary CHDSKM caused by an orthologous ABL1 gain-of-function allele was established, and there is no zoonotic or cross-species transmission. The relevant ortholog in mouse is Abl1; orthologs are broadly conserved across vertebrates. No breed-specific VBO annotation can presently be supported.

15. Model organisms and experimental systems

Mouse

Abl1-null mice provide evidence that ABL1 is essential in development, with reported growth delay, cardiac hyperplasia, osteoporosis, eye/head defects, lymphopenia, thymic/splenic abnormalities, and perinatal lethality. These are loss-of-function models and do not faithfully reproduce the human heterozygous gain-of-function syndrome; they establish developmental importance rather than allele-specific phenocopy. (wang2017germlinemutationsin pages 3-3, blakes2021pathogenicvariantscausing pages 2-3)

A disease-faithful model would require knock-in of recurrent human alleles such as p.Tyr245Cys or p.Glu528Lys, ideally conditionally in cardiac mesoderm, neural crest, endocardial/valvular, and skeletal mesenchymal lineages. No validated knock-in animal model was established in the retrieved literature.

Cellular and biochemical systems

HEK293T overexpression assays showed increased global phosphotyrosine and STAT5/STAT5B phosphorylation for multiple variants and suppression by imatinib. These assays directly support kinase gain of function but cannot reproduce embryonic tissue patterning. (blakes2021pathogenicvariantscausing pages 5-6, wang2017germlinemutationsin pages 3-4)

Purified-protein, NMR, and structural/biochemical studies of E528K defined the E528–R479 salt bridge, αI-helix mechanics, regulatory-core disassembly, and increased catalytic output. These provide strong molecular evidence but not organism-level developmental validation. (paladini2024themolecularbasis pages 9-10, paladini2024themolecularbasis pages 10-11, paladini2024themolecularbasis pages 6-9)

Evidence limitations and curation recommendations

The strongest evidence consists of the 2017 discovery study, the 2021 six-patient expansion with pooled 18-case phenotyping, and the 2024 structural study. Recent 2023–2024 case reports suggest continued phenotypic expansion, but their full text was not available in the retrieved evidence; novel features such as additional cardiac findings or Dandy–Walker malformation should therefore not be treated as established frequencies here.

For knowledge-base curation, annotate CHDSKM as an autosomal-dominant, germline ABL1 gain-of-function developmental disorder with congenital onset. Preserve patient-level denominators, distinguish observed findings from inferred mechanisms, and keep ABL1 deficiency and BCR::ABL1 neoplasia as separate disease entities. Epidemiology, penetrance, survival, quality of life, modifiers, omics signatures, validated biomarkers, and disease-specific therapeutic outcomes should be recorded as unknown rather than extrapolated.

References

(wang2017germlinemutationsin pages 3-3): Xia Wang, Wu-Lin Charng, Chun-An Chen, Jill A Rosenfeld, Aisha Al Shamsi, Lihadh Al-Gazali, Marianne McGuire, Nicholas Ah Mew, Georgianne L Arnold, Chunjing Qu, Yan Ding, Donna M Muzny, Richard A Gibbs, Christine M Eng, Magdalena Walkiewicz, Fan Xia, Sharon E Plon, James R Lupski, Christian P Schaaf, and Yaping Yang. Germline mutations in abl1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations. Mar 2017. URL: https://doi.org/10.1038/ng.3815, doi:10.1038/ng.3815. This article has 73 citations and is from a highest quality peer-reviewed journal.
(blakes2021pathogenicvariantscausing pages 3-4): Alexander J. M. Blakes, Emily Gaul, Wayne Lam, Nora Shannon, Karen M. Knapp, Louise S. Bicknell, Meremaihi R. Jackson, Emma M. Wade, Stephen Robertson, Susan M. White, Raoul Heller, Andrew Chase, Diana Baralle, and Andrew G. L. Douglas. Pathogenic variants causing abl1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity. European Journal of Human Genetics, 29:593-603, Nov 2021. URL: https://doi.org/10.1038/s41431-020-00766-w, doi:10.1038/s41431-020-00766-w. This article has 22 citations and is from a domain leading peer-reviewed journal.
(wang2017germlinemutationsin pages 1-2): Xia Wang, Wu-Lin Charng, Chun-An Chen, Jill A Rosenfeld, Aisha Al Shamsi, Lihadh Al-Gazali, Marianne McGuire, Nicholas Ah Mew, Georgianne L Arnold, Chunjing Qu, Yan Ding, Donna M Muzny, Richard A Gibbs, Christine M Eng, Magdalena Walkiewicz, Fan Xia, Sharon E Plon, James R Lupski, Christian P Schaaf, and Yaping Yang. Germline mutations in abl1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations. Mar 2017. URL: https://doi.org/10.1038/ng.3815, doi:10.1038/ng.3815. This article has 73 citations and is from a highest quality peer-reviewed journal.
(OpenTargets Search: congenital heart defects and skeletal malformations syndrome-ABL1): Open Targets Query (congenital heart defects and skeletal malformations syndrome-ABL1, 1 results). Buniello, A. et al. (2025). Open Targets Platform: facilitating therapeutic hypotheses building in drug discovery. Nucleic Acids Research.
(blakes2021pathogenicvariantscausing pages 6-8): Alexander J. M. Blakes, Emily Gaul, Wayne Lam, Nora Shannon, Karen M. Knapp, Louise S. Bicknell, Meremaihi R. Jackson, Emma M. Wade, Stephen Robertson, Susan M. White, Raoul Heller, Andrew Chase, Diana Baralle, and Andrew G. L. Douglas. Pathogenic variants causing abl1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity. European Journal of Human Genetics, 29:593-603, Nov 2021. URL: https://doi.org/10.1038/s41431-020-00766-w, doi:10.1038/s41431-020-00766-w. This article has 22 citations and is from a domain leading peer-reviewed journal.
(blakes2021pathogenicvariantscausing pages 1-2): Alexander J. M. Blakes, Emily Gaul, Wayne Lam, Nora Shannon, Karen M. Knapp, Louise S. Bicknell, Meremaihi R. Jackson, Emma M. Wade, Stephen Robertson, Susan M. White, Raoul Heller, Andrew Chase, Diana Baralle, and Andrew G. L. Douglas. Pathogenic variants causing abl1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity. European Journal of Human Genetics, 29:593-603, Nov 2021. URL: https://doi.org/10.1038/s41431-020-00766-w, doi:10.1038/s41431-020-00766-w. This article has 22 citations and is from a domain leading peer-reviewed journal.
(wang2017germlinemutationsin pages 3-4): Xia Wang, Wu-Lin Charng, Chun-An Chen, Jill A Rosenfeld, Aisha Al Shamsi, Lihadh Al-Gazali, Marianne McGuire, Nicholas Ah Mew, Georgianne L Arnold, Chunjing Qu, Yan Ding, Donna M Muzny, Richard A Gibbs, Christine M Eng, Magdalena Walkiewicz, Fan Xia, Sharon E Plon, James R Lupski, Christian P Schaaf, and Yaping Yang. Germline mutations in abl1 cause an autosomal dominant syndrome characterized by congenital heart defects and skeletal malformations. Mar 2017. URL: https://doi.org/10.1038/ng.3815, doi:10.1038/ng.3815. This article has 73 citations and is from a highest quality peer-reviewed journal.
(paladini2024themolecularbasis pages 9-10): Johannes Paladini, Annalena Maier, Judith Maria Habazettl, Ines Hertel, Rajesh Sonti, and Stephan Grzesiek. The molecular basis of abelson kinase regulation by its αi-helix. eLife, Jan 2024. URL: https://doi.org/10.1101/2023.10.04.560671, doi:10.1101/2023.10.04.560671. This article has 7 citations and is from a domain leading peer-reviewed journal.
(paladini2024themolecularbasis pages 6-9): Johannes Paladini, Annalena Maier, Judith Maria Habazettl, Ines Hertel, Rajesh Sonti, and Stephan Grzesiek. The molecular basis of abelson kinase regulation by its αi-helix. eLife, Jan 2024. URL: https://doi.org/10.1101/2023.10.04.560671, doi:10.1101/2023.10.04.560671. This article has 7 citations and is from a domain leading peer-reviewed journal.
(blakes2021pathogenicvariantscausing pages 5-6): Alexander J. M. Blakes, Emily Gaul, Wayne Lam, Nora Shannon, Karen M. Knapp, Louise S. Bicknell, Meremaihi R. Jackson, Emma M. Wade, Stephen Robertson, Susan M. White, Raoul Heller, Andrew Chase, Diana Baralle, and Andrew G. L. Douglas. Pathogenic variants causing abl1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity. European Journal of Human Genetics, 29:593-603, Nov 2021. URL: https://doi.org/10.1038/s41431-020-00766-w, doi:10.1038/s41431-020-00766-w. This article has 22 citations and is from a domain leading peer-reviewed journal.
(blakes2021pathogenicvariantscausing pages 8-9): Alexander J. M. Blakes, Emily Gaul, Wayne Lam, Nora Shannon, Karen M. Knapp, Louise S. Bicknell, Meremaihi R. Jackson, Emma M. Wade, Stephen Robertson, Susan M. White, Raoul Heller, Andrew Chase, Diana Baralle, and Andrew G. L. Douglas. Pathogenic variants causing abl1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity. European Journal of Human Genetics, 29:593-603, Nov 2021. URL: https://doi.org/10.1038/s41431-020-00766-w, doi:10.1038/s41431-020-00766-w. This article has 22 citations and is from a domain leading peer-reviewed journal.
(blakes2021pathogenicvariantscausing pages 4-5): Alexander J. M. Blakes, Emily Gaul, Wayne Lam, Nora Shannon, Karen M. Knapp, Louise S. Bicknell, Meremaihi R. Jackson, Emma M. Wade, Stephen Robertson, Susan M. White, Raoul Heller, Andrew Chase, Diana Baralle, and Andrew G. L. Douglas. Pathogenic variants causing abl1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity. European Journal of Human Genetics, 29:593-603, Nov 2021. URL: https://doi.org/10.1038/s41431-020-00766-w, doi:10.1038/s41431-020-00766-w. This article has 22 citations and is from a domain leading peer-reviewed journal.
(paladini2024themolecularbasis pages 11-12): Johannes Paladini, Annalena Maier, Judith Maria Habazettl, Ines Hertel, Rajesh Sonti, and Stephan Grzesiek. The molecular basis of abelson kinase regulation by its αi-helix. eLife, Jan 2024. URL: https://doi.org/10.1101/2023.10.04.560671, doi:10.1101/2023.10.04.560671. This article has 7 citations and is from a domain leading peer-reviewed journal.
(paladini2024themolecularbasis pages 10-11): Johannes Paladini, Annalena Maier, Judith Maria Habazettl, Ines Hertel, Rajesh Sonti, and Stephan Grzesiek. The molecular basis of abelson kinase regulation by its αi-helix. eLife, Jan 2024. URL: https://doi.org/10.1101/2023.10.04.560671, doi:10.1101/2023.10.04.560671. This article has 7 citations and is from a domain leading peer-reviewed journal.
(blakes2021pathogenicvariantscausing pages 2-3): Alexander J. M. Blakes, Emily Gaul, Wayne Lam, Nora Shannon, Karen M. Knapp, Louise S. Bicknell, Meremaihi R. Jackson, Emma M. Wade, Stephen Robertson, Susan M. White, Raoul Heller, Andrew Chase, Diana Baralle, and Andrew G. L. Douglas. Pathogenic variants causing abl1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity. European Journal of Human Genetics, 29:593-603, Nov 2021. URL: https://doi.org/10.1038/s41431-020-00766-w, doi:10.1038/s41431-020-00766-w. This article has 22 citations and is from a domain leading peer-reviewed journal.
(paladini2024themolecularbasis pages 1-2): Johannes Paladini, Annalena Maier, Judith Maria Habazettl, Ines Hertel, Rajesh Sonti, and Stephan Grzesiek. The molecular basis of abelson kinase regulation by its αi-helix. eLife, Jan 2024. URL: https://doi.org/10.1101/2023.10.04.560671, doi:10.1101/2023.10.04.560671. This article has 7 citations and is from a domain leading peer-reviewed journal.

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Pathophysiology

Pathograph

Phenotypes

Genetic Associations

Medical Actions

Differential Diagnoses

Source YAML

References & Deep Research

References

Deep Research

Disease Characteristics Research Template

Target Disease

Research Objectives

1. Disease Information

2. Etiology

3. Phenotypes

4. Genetic/Molecular Information

5. Environmental Information

6. Mechanism / Pathophysiology

7. Anatomical Structures Affected

8. Temporal Development

9. Inheritance and Population

10. Diagnostics

11. Outcome/Prognosis

12. Treatment

13. Prevention

14. Other Species / Natural Disease

15. Model Organisms

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Output Format

Congenital Heart Defects and Skeletal Malformations Syndrome (CHDSKM)

Executive summary

1. Disease information

Definition and identifiers

Scope exclusions

2. Etiology, risk, and protective factors

Primary cause

Genetic risk factors

Environmental, infectious, lifestyle, and protective factors

3. Phenotypes

Pooled phenotype frequencies

Cardiovascular

Skeletal, limb, and connective-tissue manifestations

Craniofacial, oral, hearing, growth, and neurologic features

Other organ systems

Quality of life

4. Genetic and molecular information

Gene and variant class

Allelic disorders and cancer distinction

Modifiers, epigenetics, and chromosome abnormalities

5. Environmental information

6. Mechanism and pathophysiology

Causal chain

2024 structural advance: p.Glu528Lys

Cellular and biochemical annotation

7. Anatomical structures affected

8. Temporal development and natural history

9. Inheritance and population

10. Diagnosis

Clinical recognition

Baseline clinical evaluation

Molecular testing

Differential diagnosis

Screening

11. Outcome and prognosis

12. Treatment

Current real-world management

ABL inhibitors: experimental only

13. Prevention

14. Other species and natural disease

15. Model organisms and experimental systems

Mouse

Cellular and biochemical systems

Evidence limitations and curation recommendations

Artifacts