Lethal Congenital Contracture Syndrome

Mendelian MONDO:0017436 Pathograph 28 Show in embeddings browser Congenital Disorder

Lethal congenital contracture syndrome (LCCS) is a genetically heterogeneous group of autosomal recessive fetal akinesia deformation sequence disorders in which developmental failure of the fetal motor unit abolishes fetal movement. The numbered forms (LCCS1-LCCS12) place the primary lesion at different levels of that motor unit - anterior horn motor neuron survival in LCCS1-LCCS3, Schwann cell myelination and node-of-Ranvier assembly in LCCS2 and LCCS7-LCCS9 and LCCS11, and the sarcomere and neuromuscular junction in LCCS4-LCCS6 - but they converge on the same downstream sequence: absent fetal movement, multiple joint contractures, muscle hypoplasia, micrognathia, polyhydramnios, pulmonary hypoplasia, and prenatal or early neonatal death. "Lethal" is a historical label rather than an invariant outcome: some GLDN-related infants survive the neonatal period with intensive respiratory and nutritional support.

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Inheritance

Autosomal recessive inheritance HP:0000007

Every established LCCS locus is inherited in an autosomal recessive manner, with homozygous founder alleles in consanguineous or geographically isolated kindreds and compound heterozygosity elsewhere.

Autosomal recessive inheritance

Show evidence (1 reference)

PMID:25055871 SUPPORT Human Clinical

"Lethal congenital contracture syndrome (LCCS) is a lethal autosomal recessive form of arthrogryposis multiplex congenita (AMC)."

States the autosomal recessive mode of inheritance for the LCCS group as a whole.

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Subtypes

LCCS1 (GLE1-related, Finnish type / Herva disease) MONDO:0009670

GLE1 hgnc:4315

The Finnish-heritage form, caused by biallelic GLE1 variants (classically the FinMajor splice allele). It is the most severe subtype: total fetal immobility detectable from the first trimester, hydrops, pterygia, and fetal death typically before 32 weeks, with autopsy showing loss of anterior horn motoneurons and severe ventral spinal cord atrophy.

Show evidence (1 reference)

PMID:18204449 SUPPORT Human Clinical

"Here, we report that the defective gene underlying lethal motoneuron syndrome LCCS1 is the mRNA export mediator GLE1."

Establishes GLE1 as the LCCS1 gene.

LCCS2 (ERBB3-related) MONDO:0011868

ERBB3 hgnc:3431

Described in an inbred Israeli Bedouin kindred. Distinguished from LCCS1 by the absence of hydrops, pterygia and fractures, and from LCCS3 by a markedly distended urinary bladder. Aberrant ERBB3 splicing removes an activator of PI3K/Akt signalling that is required to generate the Schwann cell precursors accompanying motor axons.

Show evidence (1 reference)

PMID:17701904 SUPPORT Human Clinical

"We show that the disease is caused by aberrant splicing of ERBB3, which leads to a predicted truncated protein."

Establishes ERBB3 as the LCCS2 gene.

LCCS3 (PIP5K1C-related) MONDO:0012656

PIP5K1C hgnc:8996

Clinically identical to LCCS2 but without bladder enlargement. Caused by biallelic PIP5K1C variants that abolish PIPKI-gamma kinase activity, reducing synthesis of PIP2, a lipid required for synaptic vesicle protein endocytosis. Later reports have extended the allelic spectrum beyond the original Bedouin D253N founder variant to truncating alleles in other populations.

Show evidence (1 reference)

PMID:17701898 SUPPORT Human Clinical

"We now describe a third LCCS phenotype (LCCS3)--similar to LCCS2 yet without neurogenic bladder."

Defines LCCS3 and its clinical discriminator from LCCS2.

LCCS4 (MYBPC1-related) MONDO:0013965

MYBPC1 hgnc:7549

Caused by a homozygous truncating MYBPC1 variant abolishing all functional domains of slow-type myosin binding protein C. The primary lesion is in the sarcomere rather than in the motor neuron. Dominant missense variants in the same gene cause the far milder distal arthrogryposis, making MYBPC1 an allelic-series exemplar within this group.

Show evidence (1 reference)

PMID:22610851 SUPPORT Human Clinical

"We now show that a recessive mutation abrogating all functional domains in the same gene leads to LCCS."

Establishes recessive MYBPC1 loss of function as the LCCS4 mechanism.

LCCS5 (DNM2-related, fetal akinesia with cerebral and retinal hemorrhage) MONDO:0014149

DNM2 hgnc:2974

Caused by a homozygous DNM2 p.Phe379Val substitution impairing endocytosis. Distinguished from the other subtypes by intracranial and retinal haemorrhages alongside the akinesia and contractures, consistent with a pleiotropic dynamin-2 requirement in both muscle and vascular development.

Show evidence (1 reference)

PMID:23092955 SUPPORT Human Clinical

"We report the first homozygous mutation in the DNM2 protein p.Phe379Val, in three consanguineous patients with a lethal congenital syndrome associating akinesia, joint contractures, hypotonia, skeletal abnormalities, and brain and retinal hemorrhages."

Establishes DNM2 and the distinguishing haemorrhagic phenotype.

LCCS6 (ZBTB42-related) MONDO:0014549

ZBTB42 hgnc:32550

Identified by autozygome analysis in a consanguineous Saudi family with recurrent stillbirths. ZBTB42 is enriched in skeletal muscle, particularly at the neuromuscular junction, and zebrafish knockdown reproduces disorganized myofibrils - placing the lesion at the muscle/NMJ end of the motor unit.

Show evidence (1 reference)

PMID:25055871 SUPPORT Human Clinical

"Our data assign a novel muscular developmental phenotype to ZBTB42 in vertebrates and establish a new LCCS6 type caused by ZBTB42 mutation."

Establishes ZBTB42 as the LCCS6 gene.

LCCS7 (CNTNAP1-related) MONDO:0014569

CNTNAP1 hgnc:8011

Caused by biallelic CNTNAP1 loss of function. CASPR is an essential paranodal component, and its loss produces a developmental nodopathy with motor nerve conduction velocities below 10 m/s and grossly abnormal nodes of Ranvier on sciatic nerve electron microscopy.

Show evidence (1 reference)

PMID:24319099 SUPPORT Human Clinical

"Homozygous frameshift mutations in CNTNAP1 were found in four unrelated families."

Establishes biallelic CNTNAP1 loss of function as an LCCS cause.

LCCS8 (ADCY6-related) MONDO:0014570

ADCY6 hgnc:237

Caused by biallelic ADCY6 variants. Adenylate cyclase 6 generates the cAMP signal that drives Schwann cell myelination, and affected nerves lack peripheral myelin entirely on electron microscopy.

Show evidence (1 reference)

PMID:24319099 SUPPORT Human Clinical

"A homozygous missense mutation in adenylate cyclase 6 gene (ADCY6) was found in another family characterized by a lack of myelin in the peripheral nervous system (PNS) as determined by TEM."

Establishes ADCY6 and the amyelinating peripheral nerve phenotype.

LCCS9 (ADGRG6/GPR126-related) MONDO:0014670

ADGRG6 hgnc:13841

Caused by biallelic ADGRG6 (GPR126) variants. GPR126 is an adhesion GPCR required for Schwann cell myelination; affected peripheral nerves lack myelin basic protein, and Gpr126-null mice reproduce the lethal arthrogryposis phenotype.

Show evidence (2 references)

PMID:26004201 SUPPORT Human Clinical

"By whole-exome or targeted exome sequencing, it was shown that the probands each harbored a different homozygous mutation (one missense, one nonsense, and one frameshift mutation) in GPR126."

Establishes biallelic GPR126/ADGRG6 variants as a cause of lethal AMC.

PMID:26004201 SUPPORT Model Organism

"A previous study reported that Gpr126(-/-) mice have a lethal arthrogryposis phenotype."

The mouse knockout evidence the subtype description relies on for recapitulation.

LCCS10 (NEK9-related) MONDO:0014870

NEK9 hgnc:18591

Caused by biallelic NEK9 variants. NEK9 is a NIMA-family kinase with roles in spindle assembly, centrosome separation and ciliogenesis, and the subtype sits at the skeletal-dysplasia end of the LCCS spectrum (thoracic dysplasia, short ribs). Allelic NEK9 disease also causes the non-lethal arthrogryposis, Perthes disease and upward gaze palsy syndrome; the phenotype tracks with variant class.

Show evidence (2 references)

PMID:36712877 SUPPORT Human Clinical

"Pathogenic variants in NEK9 (MIM: 609798) have been identified in patients with lethal congenital contracture syndrome 10 (OMIM: 617022) and arthrogryposis, Perthes disease, and upward gaze palsy"

Establishes NEK9 as the LCCS10 gene.

PMID:36712877 SUPPORT Human Clinical

"The findings from this study suggest that different types of mutations in NEK9 lead to different phenotypes."

Records the allele-dependent breadth of the NEK9 phenotype, which is why the same gene spans a lethal and a non-lethal disorder.

LCCS11 (GLDN-related) MONDO:0014965

GLDN hgnc:29514

Caused by biallelic GLDN variants. Gliomedin is the Schwann-cell-derived ligand that clusters sodium channels at nascent nodes of Ranvier through neurofascin-186, so its loss is a second developmental nodopathy alongside LCCS7. LCCS11 is the subtype with the best-documented survival beyond the neonatal period.

Show evidence (1 reference)

PMID:27616481 SUPPORT Human Clinical

"Through linkage analysis, homozygosity mapping, and exome sequencing in four unrelated families affected by lethal AMC, we identified biallelic mutations in GLDN in the affected individuals."

Establishes biallelic GLDN variants as the LCCS11 cause.

LCCS12 MONDO:0981031

DST hgnc:1090

The most recently designated member of the OMIM phenotypic series, caused by biallelic DST variants. DST encodes dystonin, a cytoskeletal linker protein; variants restricted to the DST-b isoform give a congenital myopathy, while variants that also impact DST-a give the more severe lethal congenital contracture phenotype. This places LCCS12 on the muscle/cytoskeletal side of the series rather than on either neural arm. Note that MONDO:0981031 carries no gene edge as of this curation, so the binding here is taken from the primary report rather than from MONDO.

Show evidence (2 references)

PMID:40497796 SUPPORT Human Clinical

"Genotype-phenotype correlation in these patients and previously published cases with respective variants resulted in the definition of a DST-associated lethal congenital contracture syndrome."

Establishes DST as the gene defining a lethal congenital contracture syndrome.

PMID:40497796 SUPPORT Human Clinical

"Variants that also impact DST-a besides DST-b result in a more severe, lethal congenital contracture syndrome."

Gives the isoform-dependent severity relationship that separates the lethal phenotype from the congenital myopathy.

Discussions and Knowledge Gaps

Is "lethal" still an accurate label for the LCCS group, and can the subtypes be stratified by the survival they actually achieve with modern support?

KNOWLEDGE GAP OPEN lccs_lethality_label

Attached to

pathophysiology#Neonatal Respiratory Failure has_subtypes#LCCS11

The name encodes an outcome that the evidence no longer supports uniformly. Four of six GLDN-mutated children in one series survived into infancy, childhood and late adolescence. What is missing is any denominator: the surviving cases are reported because they survived, so the published series cannot say what fraction of LCCS11 infants would survive given the same support, nor whether survival is driven by residual allele function, by the level of the motor-unit lesion, or simply by the intensity of care offered. Until that is separated out, counselling a family from the subtype label alone is not defensible.

Show evidence (1 reference)

PMID:28726266 SUPPORT Human Clinical

"Our findings expand the genotypic and phenotypic spectrum of LCCS11 and demonstrate that the condition may not necessarily be lethal in the neonatal period."

The primary source stating that the lethality implied by the name is not invariant.

Does DST-b loss reach the shared fetal-akinesia node through the same cytoskeletal/sarcomeric route as the other muscle-side subtypes, and should MONDO:0981031 carry a DST gene edge?

KNOWLEDGE GAP OPEN lccs12_gene_unassigned

Attached to

has_subtypes#LCCS12 pathophysiology#Myofibril Assembly Failure

Two separable questions. The first is an ontology gap rather than a biological one: MONDO:0981031 carries a DOID and an OMIM cross-reference but no `RO:0004003` gene edge, even though OMIM and MedGen assign DST, so the binding in this entry comes from the primary report and MONDO should be asked to add the edge. The second is genuinely open: dystonin is a cytoskeletal linker, and whether DST-b loss produces akinesia through the same contractile-apparatus failure as MYBPC1 and ZBTB42 or through a distinct cytoskeletal route has not been established. Until it is, LCCS12 is recorded as a subtype with its gene but is not placed on a trigger arm.

Show evidence (1 reference)

PMID:40497796 SUPPORT Human Clinical

"Variants that also impact DST-a besides DST-b result in a more severe, lethal congenital contracture syndrome."

Establishes the DST assignment while leaving the route from isoform loss to fetal akinesia unstated, which is what this gap records.

Does LCCS10 (NEK9) reach the contractures through the shared fetal-akinesia node at all, or through a primary skeletal route that bypasses it?

KNOWLEDGE GAP OPEN lccs10_offspine_mechanism

Attached to

has_subtypes#LCCS10 pathophysiology#Absent Fetal Movement

LCCS10 is the one numbered subtype whose arm does not join the shared fetal-akinesia node, and that is deliberate rather than an oversight. It has a molecular trigger node (`Mitotic and Ciliary Regulatory Failure`), but that node is tagged `mechanism_confidence: HYPOTHETICAL` and its only edge is an `INDIRECT_UNKNOWN_INTERMEDIATES` link straight to contracture formation, bypassing the spine. The other eleven subtypes have a lesion somewhere in the motor unit - anterior horn cell, axoglial junction, sarcomere, or endocytic machinery - and reach the contractures by way of absent fetal movement. NEK9 is a mitotic and ciliary regulator, MONDO files the subtype as a skeletal dysplasia with thoracic dysplasia and short ribs, and the reported pulmonary hypoplasia is at least as attributable to thoracic constraint as to absent fetal breathing. Whether the arthrogryposis in NEK9 disease is akinesia-driven like the rest of the series or a primary skeletal deformation is unresolved, and asserting a motor-unit node for it would manufacture a mechanism the evidence does not carry. Resolving this decides whether the entry's spine is genuinely shared across all twelve subtypes. A caution for whoever picks this up: the NEK9 case literature is dominated by the allelic APUG disorder (arthrogryposis, Perthes disease and upward gaze palsy), whose patients survive and carry compound heterozygous or missense alleles, whereas LCCS10 is reported in fetuses with homozygous truncating alleles. Visceral and cardiac findings in that literature - pyloric stenosis, septal defects, pulmonic stenosis - belong to APUG patients and must not be attributed to LCCS10. An earlier draft of this entry made exactly that error, and the snippets were exact and the PMID real, so nothing in the validation stack caught it.

Show evidence (1 reference)

PMID:36712877 SUPPORT Human Clinical

"The NEK genes encode serine/threonine kinases, which play important roles in the regulation of the cell cycle and are involved in several cellular activities, such as centrosome separation, spindle assembly, chromatin condensation, nuclear envelope breakdown, spindle assembly checkpoint..."

Describes a cell-cycle and ciliary function set with no motor-unit component, which is why the NEK9 route to the shared node cannot be asserted from it.

Where does the LCCS numbered series end and the wider fetal akinesia gene list begin?

KNOWLEDGE GAP OPEN lccs_series_boundary

Attached to

differential_diagnoses#KIF21A-related fetal akinesia

Fetal akinesia has been associated with more than 166 loci, and genes such as KIF21A produce a phenotype indistinguishable from a numbered LCCS subtype without receiving an LCCS number. The numbering therefore reflects the order of historical discovery rather than a mechanistic boundary, which matters directly for this entry: a curator deciding whether a newly reported fetal akinesia gene belongs in `has_subtypes` or in `differential_diagnoses` has no principled criterion to apply, and the answer currently depends on whether OMIM happened to assign a series number.

Show evidence (1 reference)

PMID:34740919 SUPPORT Human Clinical

"Fetal akinesia (FA) results in variable clinical presentations and has been associated with more than 166 different disease loci."

Quantifies the locus list against which the twelve-member numbered series must be positioned.

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Pathophysiology

Nuclear mRNA Export Failure

Loss of GLE1-mediated mRNA export from the nucleus, and of the translation initiation and termination steps GLE1 regulates. This is the most proximal lesion in the entry - the point where the LCCS1 genotype acts, one level upstream of the motor neuron loss it produces. Its discoverers proposed that mRNA processing is the pathway shared with the LCCS2 and LCCS3 genes, which is the strongest claim in the literature for a molecular denominator across the anterior horn arm.

GLE1 hgnc:4315

mRNA export from nucleus GO:0006406 ↓ DECREASED

Downstream

Anterior Horn Motor Neuron Loss Motor neuron precursors cannot sustain the mRNA export their proliferation and maturation require, and die.

Show evidence (1 reference)

PMID:18204449 SUPPORT Human Clinical

"Our finding of mutated GLE1 exposes a common pathway connecting the genes implicated in LCCS1, LCCS2 and LCCS3 and elucidates mRNA processing as a critical molecular mechanism in motoneuron development and maturation."

Identifies mRNA processing as the molecular mechanism, and proposes it as the pathway shared across the anterior horn subtypes.

PI3K-Akt Signaling Loss

Loss of ERBB3-driven activation of the PI3K/Akt pathway that governs cell survival and vesicle trafficking. This is the molecular step whose failure removes the Schwann cell precursors that normally accompany motor axons, and it is the first reported human phenotype from loss of function in this receptor family.

ERBB3 hgnc:3431

phosphatidylinositol 3-kinase/protein kinase B signal transduction GO:0043491 ↓ DECREASED

Downstream

Schwann Cell Myelination Failure Without the survival signal, the Schwann cell precursor pool that would myelinate motor axons is not generated.

Show evidence (1 reference)

PMID:17701904 SUPPORT Human Clinical

"an activator of the phosphatidylinositol-3-kinase/Akt pathway--regulating cell survival and vesicle trafficking"

Names the pathway ERBB3 activates and the cellular functions it governs.

Phosphoinositide Synthesis Deficiency

Loss of PIPKI-gamma kinase activity, so phosphatidylinositol 4-phosphate is not converted to PIP2. PIP2 is required for endocytosis of synaptic vesicle proteins, which places the LCCS3 lesion in the phosphatidylinositol pathway that the LCCS2 gene also feeds.

PIP5K1C hgnc:8996

1-phosphatidylinositol-4-phosphate 5-kinase activity GO:0016308 ↓ DECREASED

Downstream

Anterior Horn Motor Neuron Loss LCCS3 presents with the same anterior horn atrophy as LCCS2, and its gene sits on the phosphatidylinositol pathway proposed as the shared route.

Show evidence (1 reference)

PMID:17701898 SUPPORT Human Clinical

"Thus, a defect in the phosphatidylinositol pathway leading to a decrease in synthesis of PIP(2), a molecule active in endocytosis of synaptic vesicle proteins, culminates in lethal congenital arthrogryposis."

States the enzymatic deficiency, the downstream lipid, and its synaptic vesicle role in one sentence.

cAMP Synthesis Deficiency

Loss of adenylate cyclase 6 activity, so the cAMP second messenger that drives the myelinating program in Schwann cells is not generated. Elevated cAMP can substitute for axonal contact in vitro, which is what makes this the proximal lesion for the ADCY6 arm rather than a bystander finding.

ADCY6 hgnc:237

cAMP biosynthetic process GO:0006171 ↓ DECREASED

Downstream

Schwann Cell Myelination Failure cAMP is the signal that upregulates the myelinating program, so its absence leaves Schwann cells present but non-myelinating.

Show evidence (1 reference)

PMID:24319099 SUPPORT Human Clinical

"ADCY6 encodes a protein that belongs to the adenylate cyclase family responsible for the synthesis of cAMP."

Identifies the enzymatic function lost in the ADCY6 subtype.

Mitotic and Ciliary Regulatory Failure

Loss of NEK9 kinase function in centrosome separation, spindle assembly and primary cilium formation. This is the one trigger arm in the entry that does not obviously converge on the motor unit: NEK9's reported functions are cell-cycle and ciliary, and MONDO files the subtype as a skeletal dysplasia. It is modeled here as a molecular node with a deliberately hedged INDIRECT edge, and the open question of how it actually reaches the contractures is recorded as a knowledge gap rather than resolved by assertion.

NEK9 hgnc:18591

cilium assembly GO:0060271 ↓ DECREASED

Downstream

Joint Contracture Formation NEK9 loss produces arthrogryposis, but whether it does so through absent fetal movement like the rest of the series or through a primary skeletal route is unresolved - hence the indirect edge that bypasses the shared akinesia node.

Show evidence (1 reference)

PMID:36712877 SUPPORT Human Clinical

Sets out the cell-cycle and ciliary function set that this node represents, and which contains no motor-unit component.

Anterior Horn Motor Neuron Loss

Loss and failed maturation of spinal anterior horn motor neurons, with severe atrophy of the ventral spinal cord. Note the process binding is deliberately `spinal cord motor neuron differentiation` DECREASED rather than a motor neuron apoptosis term: the zebrafish work cited below shows the deficit arises from apoptosis of dividing *precursors*, not of differentiated motoneurons, so an apoptosis-of-motoneurons annotation would assert what the experiment refutes. This is the defining neuropathological lesion of the original Finnish and Bedouin subtypes, and it is what makes LCCS a fetal motor neuron disease rather than a primary myopathy. GLE1 loss impairs nuclear mRNA export in motor neuron precursors; the zebrafish model shows the deficit arises from apoptosis of dividing neural precursors rather than of already-differentiated motoneurons.

spinal cord motor neuron CL:0011001

spinal cord motor neuron differentiation GO:0021522 ↓ DECREASED

ventral horn of spinal cord UBERON:0002257

Downstream

Neurogenic Skeletal Muscle Atrophy and Hypoplasia Denervation of developing skeletal muscle by the failing anterior horn motor neuron pool.

Show evidence (3 references)

PMID:18204449 SUPPORT Human Clinical

"The most severe forms of motoneuron disease manifest in utero are characterized by marked atrophy of spinal cord motoneurons and fetal immobility."

Frames LCCS1 as an in utero motor neuron disease with spinal motoneuron atrophy and consequent immobility.

PMID:17701904 SUPPORT Human Clinical

"Lethal congenital contractural syndrome type 2 (LCCS2) is an autosomal recessive neurogenic form of arthrogryposis that is associated with atrophy of the anterior horn of the spinal cord."

Records anterior horn atrophy as the neuropathological lesion in LCCS2 as well, extending the node beyond LCCS1.

PMID:22357925 SUPPORT Model Organism

"Unexpectedly, the motoneuron deficiency results from apoptosis of neural precursors, not of differentiated motoneurons."

Refines the cellular mechanism: the motoneuron loss is a precursor survival defect rather than degeneration of mature neurons.

Schwann Cell Myelination Failure

Failure of Schwann cells to generate peripheral myelin around motor axons. ERBB3 is required to generate the Schwann cell precursors that accompany motor axons; ADCY6 supplies the cAMP signal that drives myelination; and ADGRG6/GPR126 is the adhesion GPCR whose autoproteolytic activation licenses it. In ADCY6 and ADGRG6 disease the peripheral nerves are effectively amyelinated on electron microscopy or lack myelin basic protein.

Schwann cell CL:0002573 Schwann cell precursor CL:0002375

peripheral nervous system myelin formation GO:0032290 ↓ DECREASED

peripheral nervous system UBERON:0000010

Downstream

Impaired Motor Nerve Conduction Unmyelinated motor axons cannot support saltatory conduction, so impulses fail to reach the developing muscle at usable velocity.

Show evidence (4 references)

PMID:17701904 SUPPORT Human Clinical

"is essential for the generation of precursors of Schwann cells that normally accompany peripheral axons of motor neurons"

Identifies the Schwann cell precursor requirement that ERBB3 loss removes in LCCS2.

PMID:24319099 SUPPORT Model Organism

"Morpholino knockdown of the zebrafish orthologs led to severe and specific defects in peripheral myelin in spite of the presence of Schwann cells."

Shows the ADCY6 lesion is a myelination failure rather than an absence of Schwann cells.

PMID:26004201 SUPPORT Human Clinical

"We have shown that the peripheral nerves in affected individuals from one family lack myelin basic protein, suggesting that this disease in affected individuals is due to defective myelination of the peripheral axons during fetal development."

Demonstrates absent peripheral myelin in ADGRG6/GPR126-related disease in human tissue.

+ 1 more reference

Node of Ranvier Assembly Failure

Failure to build the axoglial junctions that organize the node of Ranvier. CNTNAP1 encodes CASPR, the axonal paranodal component; GLDN encodes gliomedin, the Schwann-cell ligand that clusters sodium channels at the nascent node through neurofascin-186. These two subtypes are therefore a developmental nodopathy - the myelin sheath may be present, but the node is not assembled, so the axon cannot conduct.

Schwann cell CL:0002573 spinal cord motor neuron CL:0011001

node of Ranvier GO:0033268

Downstream

Impaired Motor Nerve Conduction Without assembled nodes, sodium channels are not clustered and saltatory conduction cannot occur.

Show evidence (3 references)

PMID:24319099 SUPPORT Human Clinical

"CNTNAP1 encodes CASPR, an essential component of node of Ranvier domains which underlies saltatory conduction of action potentials along the myelinated axons, an important process for neuronal function."

States the nodal role of CASPR whose loss defines the LCCS7 lesion.

PMID:27616481 SUPPORT Human Clinical

"The axoglial contact between gliomedin and NF186 is essential for the initial clustering of Na+ channels at developing nodes."

Gives the molecular step gliomedin loss removes in LCCS11.

PMID:27616481 SUPPORT Human Clinical

"These data indicate that mutations of GLDN or CNTNAP1 (MIM: 616286), encoding essential components of the nodes of Ranvier and paranodes, respectively, lead to inherited nodopathies, a distinct disease entity among peripheral neuropathies."

Groups LCCS7 and LCCS11 explicitly as inherited nodopathies, which is why they share this node.

Impaired Motor Nerve Conduction

Motor nerve conduction velocity collapses to below 10 m/s in the axoglial subtypes, so motor commands do not reach the developing muscle. This is the point at which the demyelinating and nodopathic arms of the disease rejoin the anterior-horn arm.

neuronal action potential propagation GO:0019227 ↓ DECREASED

Downstream

Absent Fetal Movement Motor commands that cannot propagate produce no fetal muscle contraction.

Show evidence (1 reference)

PMID:24319099 SUPPORT Human Clinical

"Patients showed a marked reduction in motor nerve conduction velocity (<10 m/s)"

Quantifies the conduction failure in affected individuals.

Myofibril Assembly Failure

Failure to build a competent contractile apparatus. Recessive MYBPC1 truncation removes slow-type myosin binding protein C from the thick filament; ZBTB42 loss disorganizes myofibrils outright and is enriched at the neuromuscular junction. In both the motor neuron and its axon are intact and the lesion is in the effector.

skeletal muscle fiber CL:0008002

myofibril assembly GO:0030239 ↓ DECREASED

Downstream

Absent Fetal Movement A structurally incompetent contractile apparatus cannot generate the contraction that drives fetal movement.

Show evidence (3 references)

PMID:25055871 SUPPORT Model Organism

"Knockdown experiments of zbtb42 in zebrafish consistently resulted in grossly abnormal skeletal muscle development and myofibrillar disorganization at the microscopic level."

Shows the ZBTB42 lesion is a muscle developmental and myofibrillar defect.

PMID:25055871 SUPPORT Human Clinical

"which had been shown to be enriched in skeletal muscles, especially at the neuromuscular junction"

Locates ZBTB42 expression at the neuromuscular junction.

PMID:22610851 SUPPORT Human Clinical

"a homozygous premature stop producing mutation in MYBPC1, encoding myosin-binding protein C, slow type"

Identifies the sarcomeric thick-filament protein removed in LCCS4.

Endocytic Trafficking Failure

Impaired dynamin-2-dependent membrane fission and endocytosis. This is a separate muscle-side lesion from the myofibril one: the defect is in membrane trafficking rather than in the contractile apparatus, and its pleiotropy - dynamin-2 is required in both muscle and vascular development - is what gives LCCS5 the haemorrhagic findings the other subtypes lack.

endocytosis GO:0006897 ↓ DECREASED

Downstream

Absent Fetal Movement Disordered muscle organization downstream of the trafficking defect prevents effective fetal contraction.

Show evidence (2 references)

PMID:23092955 SUPPORT In Vitro

"In vitro membrane tubulation, trafficking and GTPase assays are consistent with an impact of the DNM2p.Phe379Val mutation on endocytosis."

Functional assays localizing the DNM2 lesion to endocytosis.

PMID:23092955 SUPPORT Model Organism

"knockdown approaches in zebrafish resulting in defects in muscle organization and angiogenesis support a pleiotropic role for DNM2 during fetal development in vertebrates and humans"

Supports the pleiotropic muscle-and-vascular role that separates this node from the purely myofibrillar one.

Neurogenic Skeletal Muscle Atrophy and Hypoplasia

Severe hypoplasia and atrophy of skeletal muscle, most marked in the lower limbs, downstream of the anterior horn cell loss. In LCCS1 fetal autopsy this is found together with ventral spinal cord atrophy and in the absence of other structural organ anomalies.

skeletal muscle fiber CL:0008002

skeletal muscle tissue development GO:0007519 ↓ DECREASED

skeletal muscle tissue UBERON:0001134

Downstream

Absent Fetal Movement Denervated, hypoplastic muscle cannot move the fetal limbs.

Show evidence (1 reference)

PMID:11810649 SUPPORT Human Clinical

"Neuropathologic examination revealed anterior horn cell loss and lateral corticospinal tract degeneration in spinal cord, with marked muscular atrophy."

Autopsy pairing of anterior horn cell loss with muscular atrophy in a fetal akinesia case.

Absent Fetal Movement

Total or near-total fetal akinesia, detectable on ultrasound from the late first or second trimester and persisting at every subsequent examination. This is the convergence node of the whole entry: every subtype, whatever the level of its primary lesion, arrives here, and everything below it is deformation secondary to the missing movement rather than a separate genetic effect.

Downstream

Joint Contracture Formation Immobile joints fix in whatever position the limb is held, and the periarticular connective tissue consolidates around it.

Pulmonary Hypoplasia Absent fetal breathing movements deprive the developing lung of the cyclical distension that drives its growth.

Impaired Swallowing Akinesia includes the swallowing musculature, so amniotic fluid is not cleared.

Show evidence (2 references)

PMID:16892327 SUPPORT Human Clinical

"Thirty-nine cases had lethal congenital contracture syndrome (LCCS) clinically characterized by total immobility of the fetus at all ultrasound examinations (12 weeks or later)"

Documents total fetal immobility as the defining clinical observation in a population-based LCCS series.

PMID:25055871 SUPPORT Human Clinical

"LCCS is genetically heterogeneous with mutations in five genes identified to date, all with a role in the innervation or contractile apparatus of skeletal muscles."

States the shared mechanistic denominator - innervation or contractile apparatus - that makes this a single convergence node across the subtypes.

Joint Contracture Formation

Fixed, non-progressive contractures of multiple joints in both upper and lower limbs, classically extended elbows with flexed knees or the reverse. Because embryonic movement is required for normal joint cavitation and skeletal maturation, the contractures are a developmental deformation and do not spontaneously reverse once formed.

limb joint UBERON:0003657

Show evidence (2 references)

PMID:26142413 SUPPORT Other

"Infants whose movement in utero is reduced or restricted and who subsequently suffer from joint dysplasia (including joint contractures) and thin hypo-mineralised bones, demonstrate that embryonic movement is crucial for appropriate skeletogenesis."

Supplies the developmental-biology basis for treating the contractures as a consequence of the missing movement.

PMID:16892327 SUPPORT Human Clinical

"multiple joint contractures in both upper and lower limbs, hydrops, and fetal death before the 32nd week of pregnancy"

Records the distribution of contractures in the LCCS series.

Impaired Swallowing

Loss of the swallowing that normally clears amniotic fluid before birth, producing polyhydramnios, and the same deficit persisting after birth as dysphagia requiring nasogastric or gastrostomy feeding. Named without "fetal" because the node spans both periods - the postnatal half is what enteral feeding targets.

Show evidence (1 reference)

PMID:35806855 SUPPORT Human Clinical

"The fetus exhibited hydrops, short long bones, fixed limb joints, absent fetal movements, and polyhydramnios."

Records polyhydramnios alongside the absent fetal movement in an LCCS11 fetus.

Pulmonary Hypoplasia

Underdevelopment of the fetal lung secondary to absent fetal breathing movements and to thoracic restriction. It is the principal proximate cause of death in liveborn infants and the reason that respiratory support determines survival more than any other single factor.

lung development GO:0030324 ↓ DECREASED

lung UBERON:0002048

Downstream

Neonatal Respiratory Failure A hypoplastic lung cannot support gas exchange after delivery.

Show evidence (2 references)

PMID:32812332 SUPPORT Human Clinical

"with emphasis on the finding of pulmonary hypoplasia, suggesting that AMC secondary to GLDN variants may be best fitted under the umbrella of fetal akinesia deformation sequence (FADS)"

Identifies pulmonary hypoplasia as the finding that places GLDN-related disease within the fetal akinesia deformation sequence.

PMID:11810649 SUPPORT Human Clinical

"Fetal akinesia deformation sequence (FADS) is a rare condition characterized by intrauterine growth retardation (IUGR), congenital limb contractures, pulmonary hypoplasia, hydramnios and craniofacial abnormalities."

Defines the deformation sequence in which pulmonary hypoplasia sits alongside the contractures.

Neonatal Respiratory Failure

Respiratory insufficiency at or shortly after birth, from the combination of pulmonary hypoplasia, weak or absent respiratory drive, diaphragmatic weakness and thoracic restriction. It is the immediate cause of death in most liveborn infants and the intervention target in those who survive.

Show evidence (2 references)

PMID:38491417 SUPPORT Human Clinical

"a rare autosomal recessive genetic disorder characterized by small gestational age, severe multiple joint contractures and muscle atrophy, early death due to respiratory failure"

Names respiratory failure as the mode of early death in LCCS3.

PMID:28726266 SUPPORT Human Clinical

"He required extensive resuscitation at birth including intubation, ventilation, chest compressions, and epinephrine administration, developed progressive respiratory failure, pneumothoraces, and pulmonary hemorrhage, and died at 40 hours of age"

A worked LCCS11 case in which progressive neonatal respiratory failure was the proximate cause of death.

⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.

●

Phenotypes

Digestive 1

Dysphagia HP:0002015

Show evidence (1 reference)

PMID:28726266 SUPPORT Human Clinical

"Insufficient swallowing aggravated by paresis of both the right vocal cord and right side of the soft palate prompted gastrostomy tube placement at 4 months of age."

Documents insufficient swallowing and the gastrostomy it required in a surviving LCCS11 child.

Genitourinary 1

Neurogenic Bladder VERY_FREQUENT HP:0000011

Show evidence (2 references)

PMID:17701904 SUPPORT Human Clinical

"is characterized by multiple joint contractures, anterior horn atrophy in the spinal cord, and a unique feature of a markedly distended urinary bladder"

The positive LCCS2 statement, naming the distended bladder as the unique feature of that subtype.

PMID:17701898 SUPPORT Human Clinical

"We now describe a third LCCS phenotype (LCCS3)--similar to LCCS2 yet without neurogenic bladder."

The complementary negative, confirming the finding discriminates LCCS2 from LCCS3.

Head and Neck 1

Micrognathia FREQUENT HP:0000347

Show evidence (2 references)

PMID:18204449 SUPPORT Human Clinical

"accompanied by hydrops, micrognatia, pulmonary hypoplasia, pterygia and multiple joint contractures"

Lists micrognathia among the characteristic LCCS1 features. The source spells it "micrognatia"; the quote preserves the source spelling.

PMID:35806855 SUPPORT Human Clinical

"confirming the prenatal diagnosis and expanding the associated phenotype spectrum with pulmonary hypoplasia, retrognathia, and clubfoot"

Confirms the same jaw finding (as retrognathia) in the LCCS11 postmortem series, showing it is not confined to LCCS1.

Limbs 1

Talipes Equinovarus FREQUENT HP:0001762

Show evidence (2 references)

PMID:38491417 SUPPORT Human Clinical

"We described the features of multiple joint contractures in our fetuses, including bilateral talipes equinovarus, stiffness in the limbs, extended knees, persistently closed hands and overlapping fingers"

Documents bilateral talipes equinovarus as part of the contracture pattern in LCCS3 fetuses.

PMID:35806855 SUPPORT Human Clinical

"confirming the prenatal diagnosis and expanding the associated phenotype spectrum with pulmonary hypoplasia, retrognathia, and clubfoot"

Confirms clubfoot in the pooled LCCS11 postmortem series, showing the finding is not restricted to one subtype.

Metabolism 1

Hydrops Fetalis FREQUENT HP:0001789

Show evidence (2 references)

PMID:16892327 SUPPORT Human Clinical

"multiple joint contractures in both upper and lower limbs, hydrops, and fetal death before the 32nd week of pregnancy"

Lists hydrops among the defining features of the Finnish LCCS (LCCS1) cases.

PMID:18204449 SUPPORT Human Clinical

"accompanied by hydrops, micrognatia, pulmonary hypoplasia, pterygia and multiple joint contractures"

Confirms hydrops as a characteristic LCCS1 feature.

Musculoskeletal 2

Skeletal Muscle Atrophy VERY_FREQUENT HP:0003202

Show evidence (2 references)

PMID:18204449 SUPPORT Human Clinical

"Neuropathological analysis shows lack of anterior horn motoneurons, severe atrophy of the ventral spinal cord and hypoplastic, nearly absent skeletal muscles"

LCCS1-specific neuropathology pairing the anterior horn cell loss with nearly absent skeletal muscle.

PMID:11810649 SUPPORT INDIRECT Human Clinical

"Neuropathologic examination revealed anterior horn cell loss and lateral corticospinal tract degeneration in spinal cord, with marked muscular atrophy."

The same pairing in an un-genotyped fetal akinesia case. Indirect because the fetus was not molecularly diagnosed as LCCS.

Severe Hypotonia FREQUENT Generalized hypotonia HP:0001290

Show evidence (1 reference)

PMID:23092955 SUPPORT Human Clinical

"a lethal congenital syndrome associating akinesia, joint contractures, hypotonia, skeletal abnormalities, and brain and retinal hemorrhages"

Lists hypotonia among the presenting features.

Nervous System 1

Areflexia HP:0001284

Show evidence (1 reference)

PMID:28726266 SUPPORT Human Clinical

"His neurologic examination was notable for myopathic facies, very weak to absent deep tendon reflexes, and symmetric atrophy and weakness of his proximal muscles."

Documents absent deep tendon reflexes on examination in a GLDN-mutated child.

Prenatal and Birth 1

Polyhydramnios FREQUENT HP:0001561

Show evidence (1 reference)

PMID:35806855 SUPPORT Human Clinical

"The fetus exhibited hydrops, short long bones, fixed limb joints, absent fetal movements, and polyhydramnios."

Records polyhydramnios in an LCCS11 fetus.

Respiratory 2

Pulmonary Hypoplasia FREQUENT HP:0002089

Show evidence (1 reference)

PMID:35806855 SUPPORT Human Clinical

"To our knowledge, among the herein 28 reviewed cases, 16 reported respiratory findings, pulmonary hypoplasia being the most frequent (75%, 12/16), followed by pulmonary insufficiency or need of respiratory support."

Quantifies pulmonary hypoplasia as the dominant respiratory finding across reviewed LCCS11 cases.

Neonatal Respiratory Failure FREQUENT HP:0002878

Show evidence (1 reference)

PMID:38491417 SUPPORT Human Clinical

"Then, she underwent vaginal delivery prematurely at 26 weeks, and the baby passed away after birth due to respiratory failure."

Documents neonatal death from respiratory failure in an LCCS3 case.

Growth 1

Intrauterine Growth Restriction FREQUENT Intrauterine growth retardation HP:0001511

Show evidence (1 reference)

PMID:35806855 SUPPORT Human Clinical

"postmortem studies confirmed the prenatal findings: distal arthrogryposis, fetal growth restriction, pulmonary hypoplasia, and retrognathia"

Postmortem confirmation of fetal growth restriction in LCCS11.

Other 8

Absent Fetal Movement VERY_FREQUENT Decreased fetal movement HP:0001558

Show evidence (1 reference)

PMID:16892327 SUPPORT Human Clinical

"Thirty-nine cases had lethal congenital contracture syndrome (LCCS) clinically characterized by total immobility of the fetus at all ultrasound examinations (12 weeks or later)"

Establishes total fetal immobility from 12 weeks as a defining clinical feature of LCCS in a population-based series.

Multiple Congenital Joint Contractures VERY_FREQUENT Multiple joint contractures HP:0002828

Show evidence (1 reference)

PMID:16892327 SUPPORT Human Clinical

"multiple joint contractures in both upper and lower limbs, hydrops, and fetal death before the 32nd week of pregnancy"

Records the contracture distribution in the LCCS cases.

Pterygia FREQUENT Pterygium HP:0001059

Show evidence (1 reference)

PMID:18204449 SUPPORT Human Clinical

"Lethal congenital contracture syndrome 1 (LCCS1, MIM 253310) is an autosomal recessive condition characterized by total immobility of the fetus, detectable at the 13th week of pregnancy, accompanied by hydrops, micrognatia, pulmonary hypoplasia, pterygia and multiple joint contractures"

Lists pterygia among the characteristic features of LCCS1 specifically, which is the subtype this phenotype is tagged to.

Reduced Motor Nerve Conduction Velocity VERY_FREQUENT Decreased motor nerve conduction velocity HP:0003431

Show evidence (1 reference)

PMID:24319099 SUPPORT Human Clinical

"Patients showed a marked reduction in motor nerve conduction velocity (<10 m/s)"

Reports the measured conduction velocities in CNTNAP1-mutated patients.

Intracranial Hemorrhage VERY_FREQUENT HP:0002170

Show evidence (1 reference)

PMID:23092955 SUPPORT Human Clinical

"in three consanguineous patients with a lethal congenital syndrome associating akinesia, joint contractures, hypotonia, skeletal abnormalities, and brain and retinal hemorrhages"

Reports the intracranial haemorrhage that helps define the DNM2 subtype.

Retinal Hemorrhage VERY_FREQUENT HP:0000573

Show evidence (1 reference)

PMID:23092955 SUPPORT Human Clinical

"in three consanguineous patients with a lethal congenital syndrome associating akinesia, joint contractures, hypotonia, skeletal abnormalities, and brain and retinal hemorrhages"

Reports retinal haemorrhage in the DNM2-mutated patients.

Overlapping Fingers HP:0010557

Show evidence (1 reference)

PMID:38491417 SUPPORT Human Clinical

"including bilateral talipes equinovarus, stiffness in the limbs, extended knees, persistently closed hands and overlapping fingers"

Documents the closed-hand and overlapping-finger posture in LCCS3 fetuses.

Vocal Cord Paresis HP:0001604

Show evidence (1 reference)

PMID:28726266 SUPPORT Human Clinical

"Insufficient swallowing aggravated by paresis of both the right vocal cord and right side of the soft palate prompted gastrostomy tube placement at 4 months of age."

Documents vocal cord paresis and its contribution to the swallowing failure.

🧬

Genetic Associations

GLE1

Gene: GLE1 hgnc:4315 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (2 references)

PMID:18204449 SUPPORT Human Clinical

Establishes GLE1 as the LCCS1 gene and proposes the shared pathway with the LCCS2 and LCCS3 genes.

PMID:28884921 SUPPORT Human Clinical

"We hypothesize that mutations that preserve function of the coiled-coil domain of GLE1 cause LAAHD whereas mutations that abolish the function of the coiled-coil domain cause LCCS."

Records the proposed genotype-severity relationship within the GLE1 allelic series.

ERBB3

Gene: ERBB3 hgnc:3431 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (1 reference)

PMID:17701904 SUPPORT Human Clinical

"This is the first report of a human phenotype resulting from loss of function of a member of this group."

Records the loss-of-function mechanism and its novelty within the receptor family.

PIP5K1C

Gene: PIP5K1C hgnc:8996 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (2 references)

PMID:17701898 SUPPORT Human Clinical

"We demonstrate that the mutation causes substitution of aspartic acid with asparagine at amino acid 253 (D253N), abrogating the kinase activity of PIPKI gamma"

Gives the founder allele and its demonstrated effect on kinase activity.

PMID:38491417 SUPPORT Human Clinical

"These findings expanded the genetic variant spectrum of PIP5K1C and enriched the clinical features of LCCS3"

Extends the PIP5K1C allelic spectrum beyond the original Bedouin founder variant.

MYBPC1

Gene: MYBPC1 hgnc:7549 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (2 references)

PMID:22610851 SUPPORT Human Clinical

"A dominant missense mutation in MYBPC1 was previously shown to cause mild distal arthrogryposis."

Contrasts the dominant missense and recessive truncating mechanisms in the same gene.

PMID:26661508 SUPPORT Human Clinical

"Heterozygous mutations in this gene are associated with distal arthrogryposis types 1b and 2, whereas a homozygous nonsense mutation is implicated in one family with lethal congenital contractural syndrome 4."

Sets out the MYBPC1 allelic series, and notes that the lethal LCCS4 end of it rests on a single reported family.

DNM2

Gene: DNM2 hgnc:2974 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (1 reference)

PMID:23092955 SUPPORT In Vitro

"In vitro membrane tubulation, trafficking and GTPase assays are consistent with an impact of the DNM2p.Phe379Val mutation on endocytosis."

Functional assays supporting an endocytic defect as the DNM2 mechanism.

ZBTB42

Gene: ZBTB42 hgnc:32550 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (1 reference)

PMID:25055871 SUPPORT Model Organism

"This severe muscular phenotype is successfully rescued with overexpression of the human wild-type ZBTB42 gene, but not with the mutant form of ZBTB42 that models the human missense change."

Allele-specific rescue in zebrafish establishing pathogenicity of the human missense change.

CNTNAP1

Gene: CNTNAP1 hgnc:8011 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (2 references)

PMID:24319099 SUPPORT Human Clinical

"Homozygous frameshift mutations in CNTNAP1 were found in four unrelated families."

Multi-family evidence for biallelic CNTNAP1 loss of function.

PMID:29882456 SUPPORT Human Clinical

"By ultrastructural evaluation, septate axoglial paranodal junctions were absent from nodes of Ranvier."

Ultrastructural confirmation in human nerve that CNTNAP1 loss removes the paranodal junction, the lesion this subtype's mechanism claims.

ADCY6

Gene: ADCY6 hgnc:237 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (1 reference)

PMID:31846058 SUPPORT Human Clinical

"ADCY6 inactivation, due to biallelic variants, have been previously associated with the lethal congenital contracture syndrome 8 (LCCS8)."

Confirms biallelic ADCY6 inactivation as the LCCS8 mechanism.

ADGRG6

Gene: ADGRG6 hgnc:13841 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (2 references)

PMID:26004201 SUPPORT In Vitro

"Previous work has suggested that autoproteolytic cleavage is important for activating GPR126 signaling"

Establishes that autoproteolytic cleavage is the activating step, the background against which the patient allele's cleavage defect is read. The paper's own assay result is quoted separately below.

PMID:26004201 SUPPORT In Vitro

"impairs autoproteolytic cleavage of GPR126"

The paper's own biochemical result, showing the patient missense allele blocks the activating cleavage step.

NEK9

Gene: NEK9 hgnc:18591 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (1 reference)

PMID:36712877 SUPPORT Human Clinical

"Pathogenic variants in NEK9 (MIM: 609798) have been identified in patients with lethal congenital contracture syndrome 10 (OMIM: 617022)"

Establishes NEK9 as the LCCS10 gene.

GLDN

Gene: GLDN hgnc:29514 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (2 references)

PMID:27616481 SUPPORT In Vitro

"The GLDN mutations found in the affected individuals abolish the cell surface localization of gliomedin and its interaction with its axonal partner, neurofascin-186 (NF186), in a cell-based assay."

Cell-based functional evidence for the loss-of-function mechanism.

PMID:32812332 SUPPORT In Vitro

"Here, we describe one additional patient currently living with the syndrome, having one novel variant, p.Leu365Phe, for which we provide functional data supporting its pathogenicity."

Adds functional support for a further GLDN allele in a surviving patient.

DST

Gene: DST hgnc:1090 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (1 reference)

PMID:40497796 SUPPORT Human Clinical

"Variants that also impact DST-a besides DST-b result in a more severe, lethal congenital contracture syndrome."

Establishes DST as causative and gives the isoform-severity relationship.

💊

Medical Actions

Mechanical Ventilation and Chronic Respiratory Support

Action: Invasive Mechanical Ventilation NCIT:C191573

Intubation and mechanical ventilation at birth, progressing where survival is achieved to tracheostomy and long-term ventilation with airway clearance. This is the intervention that separates the reported LCCS11 and LCCS8 survivors from the majority who die in the neonatal period, and it modifies outcome without touching the underlying mechanism.

Mechanism Target:

Neonatal Respiratory Failure — Substitutes for the respiratory effort that the hypoplastic lung and weak respiratory musculature cannot generate.

Show evidence (1 reference)

PMID:28726266 SUPPORT Human Clinical

"Our findings confirm the association of GLDN mutations with AMC and extend the LCCS11 phenotype by describing long-term survival with chronic respiratory and nutritional support."

Documents that chronic respiratory support is what converts a nominally lethal phenotype into long-term survival.

Show evidence (1 reference)

PMID:28726266 SUPPORT Human Clinical

"four of whom survived beyond the neonatal period into infancy, childhood, and late adolescence with intensive care and chronic respiratory and nutritional support"

Reports the survival achieved with sustained respiratory support.

Enteral Nutritional Support

Action: Enteral Tube Feeding NCIT:C93322

Nasogastric or gastrostomy feeding for the dysphagia that follows the same akinesia responsible for the polyhydramnios. Required indefinitely in survivors. Tagged DEVICE rather than BEHAVIORAL because gastrostomy feeding is a procedure delivered through an indwelling tube, not a dietary or lifestyle change.

Mechanism Target:

Impaired Swallowing — Bypasses the persistent swallowing deficit that survives into postnatal life.

Show evidence (1 reference)

PMID:28726266 SUPPORT INDIRECT Human Clinical

"chronic respiratory and nutritional support"

Names nutritional support as part of the survival regimen. Indirect because the sentence does not itself trace it to the swallowing deficit.

Show evidence (1 reference)

PMID:28726266 SUPPORT Human Clinical

"extend the LCCS11 phenotype by describing long-term survival with chronic respiratory and nutritional support"

Documents chronic nutritional support in the surviving cohort.

Genetic Counseling and Prenatal Testing

Action: Genetic Counseling NCIT:C15240

Because every established locus is autosomal recessive, molecular diagnosis in a proband converts a recurrence risk stated as "unknown" into a 25% figure and makes targeted prenatal or preimplantation testing possible in subsequent pregnancies. In a disease with no disease-modifying therapy this is the principal actionable consequence of making the diagnosis.

Show evidence (1 reference)

PMID:29959180 SUPPORT Human Clinical

"A genetic diagnosis has clinical utility as it may affect management and prognosis and informs recurrence risk, facilitating family planning decisions."

States the counselling and reproductive value of reaching a molecular diagnosis.

Palliative and Supportive Care

Action: Palliative Therapy NCIT:C15292

Multidisciplinary supportive care spanning respiratory support, nutrition, mobility and psychological support for the family, with palliative-care involvement where the presentation is uniformly severe. In a condition with no disease-modifying therapy for any subtype this is not an adjunct to treatment - it is the treatment, and the decision to escalate to tracheostomy and long-term ventilation or to move to comfort care is the substantive clinical choice families face.

Show evidence (2 references)

PMID:39457470 SUPPORT INDIRECT Other

"To date, no disease-modifying treatments have been identified for congenital SMA with associated arthrogryposis or fractures."

Establishes the absence of disease-modifying therapy in congenital motor neuron disease with arthrogryposis, which is what makes supportive and palliative care the whole of management. Indirect because the review states this for congenital SMA rather than for LCCS specifically.

PMID:39457470 SUPPORT INDIRECT Other

"These clinics focus on comprehensive supportive care, addressing various aspects of the disease, such as respiratory support, nutrition, mobility aids, and psychological assistance"

Describes the components of multidisciplinary supportive care. Indirect because the review states this for ALS clinics rather than for LCCS specifically.

Contracture Management and Rehabilitation

Action: Rehabilitation NCIT:C15315

Splinting, positioning, physiotherapy and selective orthopaedic surgery in survivors. Because the contractures are fixed deformations that formed before birth, this manages rather than reverses them, and the anaesthetic and respiratory risk of surgery is substantial in a child already ventilator dependent.

Show evidence (1 reference)

PMID:28726266 SUPPORT Human Clinical

"Four of the affected infants survived beyond the neonatal period with intensive care, chronic ventilatory and nutritional support, and rehabilitation therapy."

Records rehabilitation therapy as part of the survivor regimen.

🔬

Diagnosis

Prenatal ultrasound (PRESENT)

Serial expert ultrasound assessing fetal movement, limb position, amniotic fluid volume, hydrops, growth and thoracic development. Absent movement at every examination from about 12 weeks is the earliest and most specific finding, and club foot or fixed joints are the usual first structural clue.

Show evidence (1 reference)

PMID:35806855 SUPPORT Human Clinical

"Prenatal ultrasound imaging is crucial in its early diagnosis by identifying fetal movement limitations and the presence of club foot or joint contractures"

States the role and yield of prenatal ultrasound.

Trio exome or genome sequencing (PRESENT)

Broad sequencing rather than sequential single-gene testing, because the subtypes are clinically near-indistinguishable and the gene list is long and still growing. Diagnostic yield in arthrogryposis cohorts reaches about 60% with whole-exome sequencing.

Show evidence (2 references)

PMID:35806855 SUPPORT Human Clinical

"The diagnosis rates of arthrogryposis improve up to 60% when whole-exome sequencing (WES) is used"

Quantifies the diagnostic yield of exome sequencing.

PMID:26578207 SUPPORT Human Clinical

"A conclusive genetic diagnosis was achieved for 18 of the 38 families."

Cohort-level yield of next-generation sequencing in fetal akinesia and arthrogryposis families.

Nerve conduction study (PRESENT)

Motor nerve conduction velocity separates the axoglial subtypes (LCCS7, LCCS8, LCCS9, LCCS11), where it falls below 10 m/s, from the anterior horn cell and muscle subtypes, where the primary lesion lies elsewhere.

Show evidence (1 reference)

PMID:24319099 SUPPORT Human Clinical

"Patients showed a marked reduction in motor nerve conduction velocity (<10 m/s)"

Gives the discriminating conduction velocity threshold.

Fetal and neonatal autopsy (PRESENT)

Postmortem neuropathology remains the way the anterior horn cell subtypes are distinguished from the peripheral nerve and muscle subtypes when sequencing is uninformative, and it confirms the prenatal imaging findings.

Show evidence (1 reference)

PMID:35806855 SUPPORT Human Clinical

"postmortem studies confirmed the prenatal findings: distal arthrogryposis, fetal growth restriction, pulmonary hypoplasia, and retrognathia"

Shows postmortem confirmation of the prenatal findings.

📊

Prevalence

Finland

Birth Prevalence 3.96 per 100,000 1–9 per 100,000 LCCS1

Finnish national ascertainment of all multiple-contracture cases 1987-2002, including live births, stillbirths and terminations. The source states the rate two ways, as 1 in 25,250 and as 0.40 per 10,000; both normalize to about 3.96 per 100,000, which is the figure recorded here.

Show evidence (1 reference)

PMID:16892327 SUPPORT Human Clinical

"LCCS is noted as a unique Finnish disorder with a prevalence of 1 in 25,250 (0.40/10,000) births and is a major cause of lethal arthrogryposis in Finland."

Gives the Finnish birth prevalence of LCCS (the Finnish-heritage LCCS1 form) directly.

Finland

Birth Prevalence 14.3 per 100,000 1–9 per 10,000

All lethal arthrogryposes (not LCCS specifically) in the same Finnish series; included as the denominator against which the LCCS share should be read.

Show evidence (1 reference)

PMID:16892327 SUPPORT INDIRECT Human Clinical

"In 141 out of these cases the diagnosis could be included within lethal arthrogryposes, with a prevalence of 1 in 6,985 (1.43/10,000) births."

Reports the broader lethal-arthrogryposis birth prevalence. Indirect because it is the parent category rather than LCCS itself.

Finland

Carrier Frequency 1000.0 per 100,000 >1 in 1,000 LCCS1

Carrier frequency of the GLE1 FinMajor founder allele in 200 healthy Finnish controls.

Show evidence (1 reference)

PMID:18204449 SUPPORT Human Clinical

"we found that the carrier frequency of the LCCS1 FinMajormutation in the general Finnish population was 1%"

Gives the FinMajor carrier frequency in the general Finnish population.

Northeastern Finland

Carrier Frequency 2000.0 per 100,000 >1 in 1,000 LCCS1

Carrier frequency in the region from which most LCCS1 families originate - double the national figure, and the reason regional ancestry matters to counselling.

Show evidence (1 reference)

PMID:18204449 SUPPORT Human Clinical

"The carrier frequency in northeastern Finland, where most of the families with LCCS1 originate, was 2%."

Gives the regionally enriched carrier frequency in the LCCS1 founder population.

⚖️

Clinical Burden

High

Most affected pregnancies end in fetal death or termination, and liveborn infants usually die of respiratory failure within days to months. Survivors require tracheostomy, long-term ventilation, gastrostomy feeding and continuing orthopaedic and rehabilitative care.

Show evidence (1 reference)

PMID:28726266 SUPPORT Human Clinical

"We report six infants and children from four unrelated families with biallelic GLDN mutations, four of whom survived beyond the neonatal period into infancy, childhood, and late adolescence with intensive care and chronic respiratory and nutritional support."

Documents the intensity of support required by the survivors, and so the burden even in the least lethal subtype.

🔀

Differential Diagnoses

Conditions with similar clinical presentations that must be differentiated from Lethal Congenital Contracture Syndrome:

Lethal Arthrogryposis with Anterior Horn Cell Disease

Overlapping Features LAAHD (MONDO:0012750) is allelic with LCCS1 - same gene, same fetal akinesia, same anterior horn cell disease - and is separated only by severity and by survival to the perinatal rather than the fetal period. It is the single most important differential for LCCS1, and the proposed discriminator is molecular: alleles preserving GLE1 coiled-coil function give LAAHD, alleles abolishing it give LCCS1. Cases surviving into childhood have prompted the argument that "lethal" should be dropped from the LAAHD name too.

Show evidence (2 references)

PMID:28884921 SUPPORT Human Clinical

"Both LCCS and LAAHD are characterized by reduced fetal movements, congenital contractures, and a severe form of motor neuron disease that results in fetal death or death in the perinatal period, respectively."

States the shared phenotype and the timing difference that is the whole basis of the distinction.

PMID:28884921 SUPPORT Human Clinical

"The phenotype of LAAHD is now expanded to include multiple individuals surviving into childhood suggesting that LAAHD is a misnomer and should be re-named Arthrogryposis with Anterior Horn Cell Disease (AAHD)."

Documents the survival that undermines the "lethal" label on the allelic disorder as well as on this one.

Arthrogryposis Multiplex Congenita

Overlapping Features The parent clinical phenotype. AMC is the descriptive finding of congenital contractures in two or more body regions and covers more than 400 conditions and over 220 genes; LCCS is the lethal, prenatal-onset, autosomal recessive subset of it. Distinguishing them is a matter of severity, timing and molecular diagnosis rather than of contracture pattern.

Show evidence (1 reference)

PMID:28726266 SUPPORT Human Clinical

"AMC results from diverse mechanisms, including any condition that decreases or limits fetal movements."

States the breadth of AMC against which LCCS must be positioned.

Non-genetic fetal akinesia

Overlapping Features Fetal akinesia can also result from maternal antibody-mediated disease, oligohydramnios, uterine constraint, teratogen exposure or congenital infection. Normal karyotype and microarray in an affected fetus do not exclude LCCS, so these must be excluded clinically rather than cytogenetically.

Show evidence (1 reference)

PMID:11810649 SUPPORT Human Clinical

"The etiology of akinesia was undetermined in Case 3; no extrinsic or intrinsic cause was identified."

Illustrates that fetal akinesia cases can lack any identifiable intrinsic cause, which is what the differential is guarding against.

{ }

Source YAML

click to show

name: Lethal Congenital Contracture Syndrome
creation_date: "2026-08-28T00:00:00Z"
category: Mendelian
description: >-
  Lethal congenital contracture syndrome (LCCS) is a genetically heterogeneous
  group of autosomal recessive fetal akinesia deformation sequence disorders in
  which developmental failure of the fetal motor unit abolishes fetal movement.
  The numbered forms (LCCS1-LCCS12) place the primary lesion at different levels
  of that motor unit - anterior horn motor neuron survival in LCCS1-LCCS3,
  Schwann cell myelination and node-of-Ranvier assembly in LCCS2 and
  LCCS7-LCCS9 and LCCS11, and the sarcomere and neuromuscular junction in LCCS4-LCCS6 -
  but they converge on the same downstream sequence: absent fetal movement,
  multiple joint contractures, muscle hypoplasia, micrognathia, polyhydramnios,
  pulmonary hypoplasia, and prenatal or early neonatal death. "Lethal" is a
  historical label rather than an invariant outcome: some GLDN-related infants
  survive the neonatal period with intensive respiratory and nutritional
  support.
synonyms:
- LCCS
- Multiple contracture syndrome, Finnish type
- Herva disease
disease_term:
  preferred_term: lethal congenital contracture syndrome
  term:
    id: MONDO:0017436
    label: lethal congenital contracture syndrome
parents:
- Congenital Disorder

inheritance:
- name: Autosomal recessive inheritance
  inheritance_term:
    preferred_term: Autosomal recessive inheritance
    term:
      id: HP:0000007
      label: Autosomal recessive inheritance
  description: >-
    Every established LCCS locus is inherited in an autosomal recessive manner,
    with homozygous founder alleles in consanguineous or geographically isolated
    kindreds and compound heterozygosity elsewhere.
  evidence:
  - reference: PMID:25055871
    reference_title: ZBTB42 mutation defines a novel lethal congenital contracture syndrome (LCCS6).
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lethal congenital contracture syndrome (LCCS) is a lethal autosomal recessive form of arthrogryposis multiplex congenita (AMC)."
    explanation: >-
      States the autosomal recessive mode of inheritance for the LCCS group as a
      whole.

has_subtypes:
- name: LCCS1
  display_name: LCCS1 (GLE1-related, Finnish type / Herva disease)
  subtype_term:
    preferred_term: lethal congenital contracture syndrome 1
    term:
      id: MONDO:0009670
      label: lethal congenital contracture syndrome 1
  geography:
  - Finland
  genes:
  - preferred_term: GLE1
    term:
      id: hgnc:4315
      label: GLE1
  description: >-
    The Finnish-heritage form, caused by biallelic GLE1 variants (classically the
    FinMajor splice allele). It is the most severe subtype: total fetal immobility
    detectable from the first trimester, hydrops, pterygia, and fetal death
    typically before 32 weeks, with autopsy showing loss of anterior horn
    motoneurons and severe ventral spinal cord atrophy.
  evidence:
  - reference: PMID:18204449
    reference_title: Mutations in mRNA export mediator GLE1 result in a fetal motoneuron disease.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Here, we report that the defective gene underlying lethal motoneuron syndrome LCCS1 is the mRNA export mediator GLE1."
    explanation: Establishes GLE1 as the LCCS1 gene.
- name: LCCS2
  display_name: LCCS2 (ERBB3-related)
  subtype_term:
    preferred_term: lethal congenital contracture syndrome 2
    term:
      id: MONDO:0011868
      label: lethal congenital contracture syndrome 2
  geography:
  - Israel
  genes:
  - preferred_term: ERBB3
    term:
      id: hgnc:3431
      label: ERBB3
  description: >-
    Described in an inbred Israeli Bedouin kindred. Distinguished from LCCS1 by
    the absence of hydrops, pterygia and fractures, and from LCCS3 by a markedly
    distended urinary bladder. Aberrant ERBB3 splicing removes an activator of
    PI3K/Akt signalling that is required to generate the Schwann cell precursors
    accompanying motor axons.
  evidence:
  - reference: PMID:17701904
    reference_title: "Lethal congenital contractural syndrome type 2 (LCCS2) is caused by a mutation in ERBB3 (Her3), a modulator of the phosphatidylinositol-3-kinase/Akt pathway."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We show that the disease is caused by aberrant splicing of ERBB3, which leads to a predicted truncated protein."
    explanation: Establishes ERBB3 as the LCCS2 gene.
- name: LCCS3
  display_name: LCCS3 (PIP5K1C-related)
  subtype_term:
    preferred_term: lethal congenital contracture syndrome 3
    term:
      id: MONDO:0012656
      label: lethal congenital contracture syndrome 3
  geography:
  - Israel
  genes:
  - preferred_term: PIP5K1C
    term:
      id: hgnc:8996
      label: PIP5K1C
  description: >-
    Clinically identical to LCCS2 but without bladder enlargement. Caused by
    biallelic PIP5K1C variants that abolish PIPKI-gamma kinase activity, reducing
    synthesis of PIP2, a lipid required for synaptic vesicle protein endocytosis.
    Later reports have extended the allelic spectrum beyond the original Bedouin
    D253N founder variant to truncating alleles in other populations.
  evidence:
  - reference: PMID:17701898
    reference_title: "Lethal contractural syndrome type 3 (LCCS3) is caused by a mutation in PIP5K1C, which encodes PIPKI gamma of the phophatidylinsitol pathway."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We now describe a third LCCS phenotype (LCCS3)--similar to LCCS2 yet without neurogenic bladder."
    explanation: >-
      Defines LCCS3 and its clinical discriminator from LCCS2.
- name: LCCS4
  display_name: LCCS4 (MYBPC1-related)
  subtype_term:
    preferred_term: lethal congenital contracture syndrome 4
    term:
      id: MONDO:0013965
      label: lethal congenital contracture syndrome 4
  genes:
  - preferred_term: MYBPC1
    term:
      id: hgnc:7549
      label: MYBPC1
  description: >-
    Caused by a homozygous truncating MYBPC1 variant abolishing all functional
    domains of slow-type myosin binding protein C. The primary lesion is in the
    sarcomere rather than in the motor neuron. Dominant missense variants in the
    same gene cause the far milder distal arthrogryposis, making MYBPC1 an
    allelic-series exemplar within this group.
  evidence:
  - reference: PMID:22610851
    reference_title: Autosomal recessive lethal congenital contractural syndrome type 4 (LCCS4) caused by a mutation in MYBPC1.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We now show that a recessive mutation abrogating all functional domains in the same gene leads to LCCS."
    explanation: Establishes recessive MYBPC1 loss of function as the LCCS4 mechanism.
- name: LCCS5
  display_name: LCCS5 (DNM2-related, fetal akinesia with cerebral and retinal hemorrhage)
  subtype_term:
    preferred_term: fetal akinesia-cerebral and retinal hemorrhage syndrome
    term:
      id: MONDO:0014149
      label: fetal akinesia-cerebral and retinal hemorrhage syndrome
  genes:
  - preferred_term: DNM2
    term:
      id: hgnc:2974
      label: DNM2
  description: >-
    Caused by a homozygous DNM2 p.Phe379Val substitution impairing endocytosis.
    Distinguished from the other subtypes by intracranial and retinal
    haemorrhages alongside the akinesia and contractures, consistent with a
    pleiotropic dynamin-2 requirement in both muscle and vascular development.
  evidence:
  - reference: PMID:23092955
    reference_title: Dynamin 2 homozygous mutation in humans with a lethal congenital syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report the first homozygous mutation in the DNM2 protein p.Phe379Val, in three consanguineous patients with a lethal congenital syndrome associating akinesia, joint contractures, hypotonia, skeletal abnormalities, and brain and retinal hemorrhages."
    explanation: Establishes DNM2 and the distinguishing haemorrhagic phenotype.
- name: LCCS6
  display_name: LCCS6 (ZBTB42-related)
  subtype_term:
    preferred_term: lethal congenital contracture syndrome 6
    term:
      id: MONDO:0014549
      label: lethal congenital contracture syndrome 6
  geography:
  - Saudi Arabia
  genes:
  - preferred_term: ZBTB42
    term:
      id: hgnc:32550
      label: ZBTB42
  description: >-
    Identified by autozygome analysis in a consanguineous Saudi family with
    recurrent stillbirths. ZBTB42 is enriched in skeletal muscle, particularly at
    the neuromuscular junction, and zebrafish knockdown reproduces disorganized
    myofibrils - placing the lesion at the muscle/NMJ end of the motor unit.
  evidence:
  - reference: PMID:25055871
    reference_title: ZBTB42 mutation defines a novel lethal congenital contracture syndrome (LCCS6).
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Our data assign a novel muscular developmental phenotype to ZBTB42 in vertebrates and establish a new LCCS6 type caused by ZBTB42 mutation."
    explanation: Establishes ZBTB42 as the LCCS6 gene.
- name: LCCS7
  display_name: LCCS7 (CNTNAP1-related)
  subtype_term:
    preferred_term: lethal congenital contracture syndrome 7
    term:
      id: MONDO:0014569
      label: lethal congenital contracture syndrome 7
  genes:
  - preferred_term: CNTNAP1
    term:
      id: hgnc:8011
      label: CNTNAP1
  description: >-
    Caused by biallelic CNTNAP1 loss of function. CASPR is an essential paranodal
    component, and its loss produces a developmental nodopathy with motor nerve
    conduction velocities below 10 m/s and grossly abnormal nodes of Ranvier on
    sciatic nerve electron microscopy.
  evidence:
  - reference: PMID:24319099
    reference_title: Mutations in CNTNAP1 and ADCY6 are responsible for severe arthrogryposis multiplex congenita with axoglial defects.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Homozygous frameshift mutations in CNTNAP1 were found in four unrelated families."
    explanation: Establishes biallelic CNTNAP1 loss of function as an LCCS cause.
- name: LCCS8
  display_name: LCCS8 (ADCY6-related)
  subtype_term:
    preferred_term: lethal congenital contracture syndrome 8
    term:
      id: MONDO:0014570
      label: lethal congenital contracture syndrome 8
  genes:
  - preferred_term: ADCY6
    term:
      id: hgnc:237
      label: ADCY6
  description: >-
    Caused by biallelic ADCY6 variants. Adenylate cyclase 6 generates the cAMP
    signal that drives Schwann cell myelination, and affected nerves lack
    peripheral myelin entirely on electron microscopy.
  evidence:
  - reference: PMID:24319099
    reference_title: Mutations in CNTNAP1 and ADCY6 are responsible for severe arthrogryposis multiplex congenita with axoglial defects.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A homozygous missense mutation in adenylate cyclase 6 gene (ADCY6) was found in another family characterized by a lack of myelin in the peripheral nervous system (PNS) as determined by TEM."
    explanation: Establishes ADCY6 and the amyelinating peripheral nerve phenotype.
- name: LCCS9
  display_name: LCCS9 (ADGRG6/GPR126-related)
  subtype_term:
    preferred_term: lethal congenital contracture syndrome 9
    term:
      id: MONDO:0014670
      label: lethal congenital contracture syndrome 9
  genes:
  - preferred_term: ADGRG6
    term:
      id: hgnc:13841
      label: ADGRG6
  description: >-
    Caused by biallelic ADGRG6 (GPR126) variants. GPR126 is an adhesion GPCR
    required for Schwann cell myelination; affected peripheral nerves lack myelin
    basic protein, and Gpr126-null mice reproduce the lethal arthrogryposis
    phenotype.
  evidence:
  - reference: PMID:26004201
    reference_title: Mutations of GPR126 are responsible for severe arthrogryposis multiplex congenita.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "By whole-exome or targeted exome sequencing, it was shown that the probands each harbored a different homozygous mutation (one missense, one nonsense, and one frameshift mutation) in GPR126."
    explanation: Establishes biallelic GPR126/ADGRG6 variants as a cause of lethal AMC.
  - reference: PMID:26004201
    reference_title: Mutations of GPR126 are responsible for severe arthrogryposis multiplex congenita.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "A previous study reported that Gpr126(-/-) mice have a lethal arthrogryposis phenotype."
    explanation: >-
      The mouse knockout evidence the subtype description relies on for
      recapitulation.
- name: LCCS10
  display_name: LCCS10 (NEK9-related)
  subtype_term:
    preferred_term: NEK9-related lethal skeletal dysplasia
    term:
      id: MONDO:0014870
      label: NEK9-related lethal skeletal dysplasia
  genes:
  - preferred_term: NEK9
    term:
      id: hgnc:18591
      label: NEK9
  description: >-
    Caused by biallelic NEK9 variants. NEK9 is a NIMA-family kinase with roles in
    spindle assembly, centrosome separation and ciliogenesis, and the subtype sits
    at the skeletal-dysplasia end of the LCCS spectrum (thoracic dysplasia, short
    ribs). Allelic NEK9 disease also causes the non-lethal arthrogryposis, Perthes
    disease and upward gaze palsy syndrome; the phenotype tracks with variant
    class.
  evidence:
  - reference: PMID:36712877
    reference_title: "Novel variants of NEK9 associated with neonatal arthrogryposis: Two case reports and a literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Pathogenic variants in NEK9 (MIM: 609798) have been identified in patients with lethal congenital contracture syndrome 10 (OMIM: 617022) and arthrogryposis, Perthes disease, and upward gaze palsy"
    explanation: Establishes NEK9 as the LCCS10 gene.
  - reference: PMID:36712877
    reference_title: "Novel variants of NEK9 associated with neonatal arthrogryposis: Two case reports and a literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The findings from this study suggest that different types of mutations in NEK9 lead to different phenotypes."
    explanation: >-
      Records the allele-dependent breadth of the NEK9 phenotype, which is why the
      same gene spans a lethal and a non-lethal disorder.
- name: LCCS11
  display_name: LCCS11 (GLDN-related)
  subtype_term:
    preferred_term: lethal congenital contracture syndrome 11
    term:
      id: MONDO:0014965
      label: lethal congenital contracture syndrome 11
  genes:
  - preferred_term: GLDN
    term:
      id: hgnc:29514
      label: GLDN
  description: >-
    Caused by biallelic GLDN variants. Gliomedin is the Schwann-cell-derived
    ligand that clusters sodium channels at nascent nodes of Ranvier through
    neurofascin-186, so its loss is a second developmental nodopathy alongside
    LCCS7. LCCS11 is the subtype with the best-documented survival beyond the
    neonatal period.
  evidence:
  - reference: PMID:27616481
    reference_title: "Mutations in GLDN, Encoding Gliomedin, a Critical Component of the Nodes of Ranvier, Are Responsible for Lethal Arthrogryposis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Through linkage analysis, homozygosity mapping, and exome sequencing in four unrelated families affected by lethal AMC, we identified biallelic mutations in GLDN in the affected individuals."
    explanation: Establishes biallelic GLDN variants as the LCCS11 cause.
- name: LCCS12
  display_name: LCCS12
  subtype_term:
    preferred_term: lethal congenital contracture syndrome 12
    term:
      id: MONDO:0981031
      label: lethal congenital contracture syndrome 12
  genes:
  - preferred_term: DST
    term:
      id: hgnc:1090
      label: DST
  description: >-
    The most recently designated member of the OMIM phenotypic series, caused by
    biallelic DST variants. DST encodes dystonin, a cytoskeletal linker protein;
    variants restricted to the DST-b isoform give a congenital myopathy, while
    variants that also impact DST-a give the more severe lethal congenital
    contracture phenotype. This places LCCS12 on the muscle/cytoskeletal side of
    the series rather than on either neural arm. Note that MONDO:0981031 carries
    no gene edge as of this curation, so the binding here is taken from the
    primary report rather than from MONDO.
  evidence:
  - reference: PMID:40497796
    reference_title: "Deciphering DST-associated disorders: biallelic variants affecting DST-b cause a congenital myopathy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Genotype-phenotype correlation in these patients and previously published cases with respective variants resulted in the definition of a DST-associated lethal congenital contracture syndrome."
    explanation: >-
      Establishes DST as the gene defining a lethal congenital contracture
      syndrome.
  - reference: PMID:40497796
    reference_title: "Deciphering DST-associated disorders: biallelic variants affecting DST-b cause a congenital myopathy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Variants that also impact DST-a besides DST-b result in a more severe, lethal congenital contracture syndrome."
    explanation: >-
      Gives the isoform-dependent severity relationship that separates the lethal
      phenotype from the congenital myopathy.

prevalence:
- subtype: LCCS1
  population: Finland
  measure_type: BIRTH_PREVALENCE
  prevalence_class: BAND_1_9_PER_100000
  rate_per_100000: 3.96
  notes: >-
    Finnish national ascertainment of all multiple-contracture cases 1987-2002,
    including live births, stillbirths and terminations. The source states the
    rate two ways, as 1 in 25,250 and as 0.40 per 10,000; both normalize to
    about 3.96 per 100,000, which is the figure recorded here.
  evidence:
  - reference: PMID:16892327
    reference_title: Lethal congenital contracture syndrome (LCCS) and other lethal arthrogryposes in Finland--an epidemiological study.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "LCCS is noted as a unique Finnish disorder with a prevalence of 1 in 25,250 (0.40/10,000) births and is a major cause of lethal arthrogryposis in Finland."
    explanation: >-
      Gives the Finnish birth prevalence of LCCS (the Finnish-heritage LCCS1 form)
      directly.
- population: Finland
  measure_type: BIRTH_PREVALENCE
  prevalence_class: BAND_1_5_PER_10000
  rate_per_100000: 14.3
  notes: >-
    All lethal arthrogryposes (not LCCS specifically) in the same Finnish series;
    included as the denominator against which the LCCS share should be read.
  evidence:
  - reference: PMID:16892327
    reference_title: Lethal congenital contracture syndrome (LCCS) and other lethal arthrogryposes in Finland--an epidemiological study.
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: "In 141 out of these cases the diagnosis could be included within lethal arthrogryposes, with a prevalence of 1 in 6,985 (1.43/10,000) births."
    explanation: >-
      Reports the broader lethal-arthrogryposis birth prevalence. Indirect because
      it is the parent category rather than LCCS itself.

- subtype: LCCS1
  population: Finland
  measure_type: CARRIER_FREQUENCY
  prevalence_class: ABOVE_1_IN_1000
  rate_per_100000: 1000.0
  notes: >-
    Carrier frequency of the GLE1 FinMajor founder allele in 200 healthy Finnish
    controls.
  evidence:
  - reference: PMID:18204449
    reference_title: Mutations in mRNA export mediator GLE1 result in a fetal motoneuron disease.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "we found that the carrier frequency of the LCCS1 FinMajormutation in the general Finnish population was 1%"
    explanation: >-
      Gives the FinMajor carrier frequency in the general Finnish population.
- subtype: LCCS1
  population: Northeastern Finland
  measure_type: CARRIER_FREQUENCY
  prevalence_class: ABOVE_1_IN_1000
  rate_per_100000: 2000.0
  notes: >-
    Carrier frequency in the region from which most LCCS1 families originate -
    double the national figure, and the reason regional ancestry matters to
    counselling.
  evidence:
  - reference: PMID:18204449
    reference_title: Mutations in mRNA export mediator GLE1 result in a fetal motoneuron disease.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The carrier frequency in northeastern Finland, where most of the families with LCCS1 originate, was 2%."
    explanation: >-
      Gives the regionally enriched carrier frequency in the LCCS1 founder
      population.

clinical_burden:
  burden_level: HIGH
  rationale: >-
    Most affected pregnancies end in fetal death or termination, and liveborn
    infants usually die of respiratory failure within days to months. Survivors
    require tracheostomy, long-term ventilation, gastrostomy feeding and
    continuing orthopaedic and rehabilitative care.
  evidence:
  - reference: PMID:28726266
    reference_title: "Survival among children with \"Lethal\" congenital contracture syndrome 11 caused by novel mutations in the gliomedin gene (GLDN)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report six infants and children from four unrelated families with biallelic GLDN mutations, four of whom survived beyond the neonatal period into infancy, childhood, and late adolescence with intensive care and chronic respiratory and nutritional support."
    explanation: >-
      Documents the intensity of support required by the survivors, and so the
      burden even in the least lethal subtype.

pathophysiology:
- name: Nuclear mRNA Export Failure
  biological_scale: MOLECULAR
  subtypes:
  - LCCS1
  description: >-
    Loss of GLE1-mediated mRNA export from the nucleus, and of the translation
    initiation and termination steps GLE1 regulates. This is the most proximal
    lesion in the entry - the point where the LCCS1 genotype acts, one level
    upstream of the motor neuron loss it produces. Its discoverers proposed that
    mRNA processing is the pathway shared with the LCCS2 and LCCS3 genes, which
    is the strongest claim in the literature for a molecular denominator across
    the anterior horn arm.
  biological_processes:
  - preferred_term: mRNA export from nucleus
    term:
      id: GO:0006406
      label: mRNA export from nucleus
    modifier: DECREASED
  genes:
  - preferred_term: GLE1
    term:
      id: hgnc:4315
      label: GLE1
  evidence:
  - reference: PMID:18204449
    reference_title: Mutations in mRNA export mediator GLE1 result in a fetal motoneuron disease.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Our finding of mutated GLE1 exposes a common pathway connecting the genes implicated in LCCS1, LCCS2 and LCCS3 and elucidates mRNA processing as a critical molecular mechanism in motoneuron development and maturation."
    explanation: >-
      Identifies mRNA processing as the molecular mechanism, and proposes it as
      the pathway shared across the anterior horn subtypes.
  downstream:
  - target: Anterior Horn Motor Neuron Loss
    causal_link_type: DIRECT
    description: >-
      Motor neuron precursors cannot sustain the mRNA export their proliferation
      and maturation require, and die.
    evidence:
    - reference: PMID:22357925
      reference_title: A zebrafish model of lethal congenital contracture syndrome 1 reveals Gle1 function in spinal neural precursor survival and motor axon arborization.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "Together, our studies provide the first functional characterization of Gle1 in vertebrate development and reveal its essential role in actively dividing cells."
      explanation: >-
        Establishes the requirement for Gle1 in dividing cells, the population
        whose loss produces the motoneuron deficit.
- name: PI3K-Akt Signaling Loss
  biological_scale: MOLECULAR
  subtypes:
  - LCCS2
  description: >-
    Loss of ERBB3-driven activation of the PI3K/Akt pathway that governs cell
    survival and vesicle trafficking. This is the molecular step whose failure
    removes the Schwann cell precursors that normally accompany motor axons, and
    it is the first reported human phenotype from loss of function in this
    receptor family.
  biological_processes:
  - preferred_term: phosphatidylinositol 3-kinase/protein kinase B signal transduction
    term:
      id: GO:0043491
      label: phosphatidylinositol 3-kinase/protein kinase B signal transduction
    modifier: DECREASED
  genes:
  - preferred_term: ERBB3
    term:
      id: hgnc:3431
      label: ERBB3
  evidence:
  - reference: PMID:17701904
    reference_title: "Lethal congenital contractural syndrome type 2 (LCCS2) is caused by a mutation in ERBB3 (Her3), a modulator of the phosphatidylinositol-3-kinase/Akt pathway."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "an activator of the phosphatidylinositol-3-kinase/Akt pathway--regulating cell survival and vesicle trafficking"
    explanation: >-
      Names the pathway ERBB3 activates and the cellular functions it governs.
  downstream:
  - target: Schwann Cell Myelination Failure
    causal_link_type: DIRECT
    description: >-
      Without the survival signal, the Schwann cell precursor pool that would
      myelinate motor axons is not generated.
    evidence:
    - reference: PMID:17701904
      reference_title: "Lethal congenital contractural syndrome type 2 (LCCS2) is caused by a mutation in ERBB3 (Her3), a modulator of the phosphatidylinositol-3-kinase/Akt pathway."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "is essential for the generation of precursors of Schwann cells that normally accompany peripheral axons of motor neurons"
      explanation: >-
        States the Schwann cell precursor requirement that this signalling loss
        removes.
- name: Phosphoinositide Synthesis Deficiency
  biological_scale: MOLECULAR
  subtypes:
  - LCCS3
  description: >-
    Loss of PIPKI-gamma kinase activity, so phosphatidylinositol 4-phosphate is
    not converted to PIP2. PIP2 is required for endocytosis of synaptic vesicle
    proteins, which places the LCCS3 lesion in the phosphatidylinositol pathway
    that the LCCS2 gene also feeds.
  molecular_functions:
  - preferred_term: 1-phosphatidylinositol-4-phosphate 5-kinase activity
    term:
      id: GO:0016308
      label: 1-phosphatidylinositol-4-phosphate 5-kinase activity
    modifier: DECREASED
  genes:
  - preferred_term: PIP5K1C
    term:
      id: hgnc:8996
      label: PIP5K1C
  evidence:
  - reference: PMID:17701898
    reference_title: "Lethal contractural syndrome type 3 (LCCS3) is caused by a mutation in PIP5K1C, which encodes PIPKI gamma of the phophatidylinsitol pathway."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Thus, a defect in the phosphatidylinositol pathway leading to a decrease in synthesis of PIP(2), a molecule active in endocytosis of synaptic vesicle proteins, culminates in lethal congenital arthrogryposis."
    explanation: >-
      States the enzymatic deficiency, the downstream lipid, and its synaptic
      vesicle role in one sentence.
  downstream:
  - target: Anterior Horn Motor Neuron Loss
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      LCCS3 presents with the same anterior horn atrophy as LCCS2, and its gene
      sits on the phosphatidylinositol pathway proposed as the shared route.
    evidence:
    - reference: PMID:17701898
      reference_title: "Lethal contractural syndrome type 3 (LCCS3) is caused by a mutation in PIP5K1C, which encodes PIPKI gamma of the phophatidylinsitol pathway."
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: HUMAN_CLINICAL
      snippet: "We now describe a third LCCS phenotype (LCCS3)--similar to LCCS2 yet without neurogenic bladder."
      explanation: >-
        Establishes clinical identity with LCCS2, whose anterior horn atrophy is
        documented. Indirect because the anterior horn lesion is inferred from
        that identity rather than reported directly here.
- name: cAMP Synthesis Deficiency
  biological_scale: MOLECULAR
  subtypes:
  - LCCS8
  description: >-
    Loss of adenylate cyclase 6 activity, so the cAMP second messenger that
    drives the myelinating program in Schwann cells is not generated. Elevated
    cAMP can substitute for axonal contact in vitro, which is what makes this the
    proximal lesion for the ADCY6 arm rather than a bystander finding.
  biological_processes:
  - preferred_term: cAMP biosynthetic process
    term:
      id: GO:0006171
      label: cAMP biosynthetic process
    modifier: DECREASED
  genes:
  - preferred_term: ADCY6
    term:
      id: hgnc:237
      label: ADCY6
  evidence:
  - reference: PMID:24319099
    reference_title: Mutations in CNTNAP1 and ADCY6 are responsible for severe arthrogryposis multiplex congenita with axoglial defects.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ADCY6 encodes a protein that belongs to the adenylate cyclase family responsible for the synthesis of cAMP."
    explanation: Identifies the enzymatic function lost in the ADCY6 subtype.
  downstream:
  - target: Schwann Cell Myelination Failure
    causal_link_type: DIRECT
    description: >-
      cAMP is the signal that upregulates the myelinating program, so its
      absence leaves Schwann cells present but non-myelinating.
    evidence:
    - reference: PMID:24319099
      reference_title: Mutations in CNTNAP1 and ADCY6 are responsible for severe arthrogryposis multiplex congenita with axoglial defects.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Our data indicate an essential and so far unknown role of ADCY6 in PNS myelination likely through the cAMP pathway."
      explanation: >-
        States the cAMP-to-myelination link the authors draw from their own data.
- name: Mitotic and Ciliary Regulatory Failure
  biological_scale: MOLECULAR
  subtypes:
  - LCCS10
  description: >-
    Loss of NEK9 kinase function in centrosome separation, spindle assembly and
    primary cilium formation. This is the one trigger arm in the entry that does
    not obviously converge on the motor unit: NEK9's reported functions are
    cell-cycle and ciliary, and MONDO files the subtype as a skeletal dysplasia.
    It is modeled here as a molecular node with a deliberately hedged INDIRECT
    edge, and the open question of how it actually reaches the contractures is
    recorded as a knowledge gap rather than resolved by assertion.
  biological_processes:
  - preferred_term: cilium assembly
    term:
      id: GO:0060271
      label: cilium assembly
    modifier: DECREASED
  genes:
  - preferred_term: NEK9
    term:
      id: hgnc:18591
      label: NEK9
  mechanism_confidence: HYPOTHETICAL
  evidence:
  - reference: PMID:36712877
    reference_title: "Novel variants of NEK9 associated with neonatal arthrogryposis: Two case reports and a literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The NEK genes encode serine/threonine kinases, which play important roles in the regulation of the cell cycle and are involved in several cellular activities, such as centrosome separation, spindle assembly, chromatin condensation, nuclear envelope breakdown, spindle assembly checkpoint signaling, cytokinesis, cilia formation, and DNA damage response."
    explanation: >-
      Sets out the cell-cycle and ciliary function set that this node represents,
      and which contains no motor-unit component.
  downstream:
  - target: Joint Contracture Formation
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      NEK9 loss produces arthrogryposis, but whether it does so through absent
      fetal movement like the rest of the series or through a primary skeletal
      route is unresolved - hence the indirect edge that bypasses the shared
      akinesia node.
    evidence:
    - reference: PMID:36712877
      reference_title: "Novel variants of NEK9 associated with neonatal arthrogryposis: Two case reports and a literature review."
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: HUMAN_CLINICAL
      snippet: "The shared core phenotype is multiple joint contractures or arthrogryposis."
      explanation: >-
        Establishes the contracture outcome. Indirect because the intervening
        mechanism is exactly what this entry records as unresolved.
- name: Anterior Horn Motor Neuron Loss
  biological_scale: CELLULAR
  subtypes:
  - LCCS1
  - LCCS2
  - LCCS3
  description: >-
    Loss and failed maturation of spinal anterior horn motor neurons, with
    severe atrophy of the ventral spinal cord. Note the process binding is
    deliberately `spinal cord motor neuron differentiation` DECREASED rather
    than a motor neuron apoptosis term: the zebrafish work cited below shows the
    deficit arises from apoptosis of dividing *precursors*, not of
    differentiated motoneurons, so an apoptosis-of-motoneurons annotation would
    assert what the experiment refutes. This is the defining
    neuropathological lesion of the original Finnish and Bedouin subtypes, and
    it is what makes LCCS a fetal motor neuron disease rather than a primary
    myopathy. GLE1 loss impairs nuclear mRNA export in motor neuron precursors;
    the zebrafish model shows the deficit arises from apoptosis of dividing
    neural precursors rather than of already-differentiated motoneurons.
  cell_types:
  - preferred_term: spinal cord motor neuron
    term:
      id: CL:0011001
      label: spinal cord motor neuron
  biological_processes:
  - preferred_term: spinal cord motor neuron differentiation
    term:
      id: GO:0021522
      label: spinal cord motor neuron differentiation
    modifier: DECREASED
  locations:
  - preferred_term: ventral horn of spinal cord
    term:
      id: UBERON:0002257
      label: ventral horn of spinal cord
  evidence:
  - reference: PMID:18204449
    reference_title: Mutations in mRNA export mediator GLE1 result in a fetal motoneuron disease.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The most severe forms of motoneuron disease manifest in utero are characterized by marked atrophy of spinal cord motoneurons and fetal immobility."
    explanation: >-
      Frames LCCS1 as an in utero motor neuron disease with spinal motoneuron
      atrophy and consequent immobility.
  - reference: PMID:17701904
    reference_title: "Lethal congenital contractural syndrome type 2 (LCCS2) is caused by a mutation in ERBB3 (Her3), a modulator of the phosphatidylinositol-3-kinase/Akt pathway."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lethal congenital contractural syndrome type 2 (LCCS2) is an autosomal recessive neurogenic form of arthrogryposis that is associated with atrophy of the anterior horn of the spinal cord."
    explanation: >-
      Records anterior horn atrophy as the neuropathological lesion in LCCS2 as
      well, extending the node beyond LCCS1.
  - reference: PMID:22357925
    reference_title: A zebrafish model of lethal congenital contracture syndrome 1 reveals Gle1 function in spinal neural precursor survival and motor axon arborization.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Unexpectedly, the motoneuron deficiency results from apoptosis of neural precursors, not of differentiated motoneurons."
    explanation: >-
      Refines the cellular mechanism: the motoneuron loss is a precursor survival
      defect rather than degeneration of mature neurons.
  downstream:
  - target: Neurogenic Skeletal Muscle Atrophy and Hypoplasia
    causal_link_type: DIRECT
    description: >-
      Denervation of developing skeletal muscle by the failing anterior horn
      motor neuron pool.
    evidence:
    - reference: PMID:18204449
      reference_title: Mutations in mRNA export mediator GLE1 result in a fetal motoneuron disease.
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: HUMAN_CLINICAL
      snippet: "The most severe forms of motoneuron disease manifest in utero are characterized by marked atrophy of spinal cord motoneurons and fetal immobility."
      explanation: >-
        Couples motoneuron atrophy to fetal immobility. Indirect because the
        intervening muscle denervation step is stated in the fetal pathology
        literature rather than in this sentence.
- name: Schwann Cell Myelination Failure
  biological_scale: CELLULAR
  subtypes:
  - LCCS2
  - LCCS8
  - LCCS9
  description: >-
    Failure of Schwann cells to generate peripheral myelin around motor axons.
    ERBB3 is required to generate the Schwann cell precursors that accompany
    motor axons; ADCY6 supplies the cAMP signal that drives myelination; and
    ADGRG6/GPR126 is the adhesion GPCR whose autoproteolytic activation licenses
    it. In ADCY6 and ADGRG6 disease the peripheral nerves are effectively
    amyelinated on electron microscopy or lack myelin basic protein.
  cell_types:
  - preferred_term: Schwann cell
    term:
      id: CL:0002573
      label: Schwann cell
  - preferred_term: Schwann cell precursor
    term:
      id: CL:0002375
      label: Schwann cell precursor
  biological_processes:
  - preferred_term: peripheral nervous system myelin formation
    term:
      id: GO:0032290
      label: peripheral nervous system myelin formation
    modifier: DECREASED
  locations:
  - preferred_term: peripheral nervous system
    term:
      id: UBERON:0000010
      label: peripheral nervous system
  evidence:
  - reference: PMID:17701904
    reference_title: "Lethal congenital contractural syndrome type 2 (LCCS2) is caused by a mutation in ERBB3 (Her3), a modulator of the phosphatidylinositol-3-kinase/Akt pathway."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "is essential for the generation of precursors of Schwann cells that normally accompany peripheral axons of motor neurons"
    explanation: >-
      Identifies the Schwann cell precursor requirement that ERBB3 loss removes in
      LCCS2.
  - reference: PMID:24319099
    reference_title: Mutations in CNTNAP1 and ADCY6 are responsible for severe arthrogryposis multiplex congenita with axoglial defects.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Morpholino knockdown of the zebrafish orthologs led to severe and specific defects in peripheral myelin in spite of the presence of Schwann cells."
    explanation: >-
      Shows the ADCY6 lesion is a myelination failure rather than an absence of
      Schwann cells.
  - reference: PMID:26004201
    reference_title: Mutations of GPR126 are responsible for severe arthrogryposis multiplex congenita.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We have shown that the peripheral nerves in affected individuals from one family lack myelin basic protein, suggesting that this disease in affected individuals is due to defective myelination of the peripheral axons during fetal development."
    explanation: >-
      Demonstrates absent peripheral myelin in ADGRG6/GPR126-related disease in
      human tissue.
  - reference: PMID:26921650
    reference_title: Deficiency in the mRNA export mediator Gle1 impairs Schwann cell development in the zebrafish embryo.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Other genes mutated in LCCS have important roles in Schwann cell development, thereby suggesting that Schwann cell deficits may be a common factor in LCCS pathogenesis."
    explanation: >-
      Argues that Schwann cell failure is shared more widely across LCCS than the
      three subtypes tagged on this node, including the nominally anterior-horn
      GLE1 form - a reason to treat this node as broader than its current tags.
  downstream:
  - target: Impaired Motor Nerve Conduction
    causal_link_type: DIRECT
    description: >-
      Unmyelinated motor axons cannot support saltatory conduction, so impulses
      fail to reach the developing muscle at usable velocity.
    evidence:
    - reference: PMID:26004201
      reference_title: Mutations of GPR126 are responsible for severe arthrogryposis multiplex congenita.
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: HUMAN_CLINICAL
      snippet: "GPR126 encodes G-protein-coupled receptor 126, which has been shown to be essential for myelination of axons in the peripheral nervous system in fish and mice."
      explanation: >-
        Establishes the myelination requirement. Indirect because the conduction
        measurement itself is reported for the nodopathy subtypes rather than here.
- name: Node of Ranvier Assembly Failure
  biological_scale: CELLULAR
  subtypes:
  - LCCS7
  - LCCS11
  description: >-
    Failure to build the axoglial junctions that organize the node of Ranvier.
    CNTNAP1 encodes CASPR, the axonal paranodal component; GLDN encodes
    gliomedin, the Schwann-cell ligand that clusters sodium channels at the
    nascent node through neurofascin-186. These two subtypes are therefore a
    developmental nodopathy - the myelin sheath may be present, but the node is
    not assembled, so the axon cannot conduct.
  cell_types:
  - preferred_term: Schwann cell
    term:
      id: CL:0002573
      label: Schwann cell
  - preferred_term: spinal cord motor neuron
    term:
      id: CL:0011001
      label: spinal cord motor neuron
  cellular_components:
  - preferred_term: node of Ranvier
    term:
      id: GO:0033268
      label: node of Ranvier
  evidence:
  - reference: PMID:24319099
    reference_title: Mutations in CNTNAP1 and ADCY6 are responsible for severe arthrogryposis multiplex congenita with axoglial defects.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "CNTNAP1 encodes CASPR, an essential component of node of Ranvier domains which underlies saltatory conduction of action potentials along the myelinated axons, an important process for neuronal function."
    explanation: >-
      States the nodal role of CASPR whose loss defines the LCCS7 lesion.
  - reference: PMID:27616481
    reference_title: "Mutations in GLDN, Encoding Gliomedin, a Critical Component of the Nodes of Ranvier, Are Responsible for Lethal Arthrogryposis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The axoglial contact between gliomedin and NF186 is essential for the initial clustering of Na+ channels at developing nodes."
    explanation: >-
      Gives the molecular step gliomedin loss removes in LCCS11.
  - reference: PMID:27616481
    reference_title: "Mutations in GLDN, Encoding Gliomedin, a Critical Component of the Nodes of Ranvier, Are Responsible for Lethal Arthrogryposis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "These data indicate that mutations of GLDN or CNTNAP1 (MIM: 616286), encoding essential components of the nodes of Ranvier and paranodes, respectively, lead to inherited nodopathies, a distinct disease entity among peripheral neuropathies."
    explanation: >-
      Groups LCCS7 and LCCS11 explicitly as inherited nodopathies, which is why
      they share this node.
  downstream:
  - target: Impaired Motor Nerve Conduction
    causal_link_type: DIRECT
    description: >-
      Without assembled nodes, sodium channels are not clustered and saltatory
      conduction cannot occur.
    evidence:
    - reference: PMID:24319099
      reference_title: Mutations in CNTNAP1 and ADCY6 are responsible for severe arthrogryposis multiplex congenita with axoglial defects.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Patients showed a marked reduction in motor nerve conduction velocity (<10 m/s) and transmission electron microscopy (TEM) of sciatic nerve in the index cases revealed severe abnormalities of both nodes of Ranvier width and myelinated axons."
      explanation: >-
        Directly pairs the nodal abnormality with the measured conduction failure
        in the same patients.
- name: Impaired Motor Nerve Conduction
  biological_scale: CELLULAR
  subtypes:
  - LCCS7
  - LCCS8
  - LCCS9
  - LCCS11
  description: >-
    Motor nerve conduction velocity collapses to below 10 m/s in the axoglial
    subtypes, so motor commands do not reach the developing muscle. This is the
    point at which the demyelinating and nodopathic arms of the disease rejoin
    the anterior-horn arm.
  biological_processes:
  - preferred_term: neuronal action potential propagation
    term:
      id: GO:0019227
      label: neuronal action potential propagation
    modifier: DECREASED
  evidence:
  - reference: PMID:24319099
    reference_title: Mutations in CNTNAP1 and ADCY6 are responsible for severe arthrogryposis multiplex congenita with axoglial defects.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Patients showed a marked reduction in motor nerve conduction velocity (<10 m/s)"
    explanation: Quantifies the conduction failure in affected individuals.
  downstream:
  - target: Absent Fetal Movement
    causal_link_type: DIRECT
    description: >-
      Motor commands that cannot propagate produce no fetal muscle contraction.
    evidence:
    - reference: PMID:24319099
      reference_title: Mutations in CNTNAP1 and ADCY6 are responsible for severe arthrogryposis multiplex congenita with axoglial defects.
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: HUMAN_CLINICAL
      snippet: "Non-syndromic arthrogryposis multiplex congenita (AMC) is characterized by multiple congenital contractures resulting from reduced fetal mobility."
      explanation: >-
        Places the cohort's conduction defect within the reduced-fetal-mobility
        causal frame. Indirect because the sentence states the frame rather than
        measuring the conduction-to-movement step.
- name: Myofibril Assembly Failure
  biological_scale: CELLULAR
  subtypes:
  - LCCS4
  - LCCS6
  description: >-
    Failure to build a competent contractile apparatus. Recessive MYBPC1
    truncation removes slow-type myosin binding protein C from the thick
    filament; ZBTB42 loss disorganizes myofibrils outright and is enriched at the
    neuromuscular junction. In both the motor neuron and its axon are intact and
    the lesion is in the effector.
  cell_types:
  - preferred_term: skeletal muscle fiber
    term:
      id: CL:0008002
      label: skeletal muscle fiber
  biological_processes:
  - preferred_term: myofibril assembly
    term:
      id: GO:0030239
      label: myofibril assembly
    modifier: DECREASED
  evidence:
  - reference: PMID:25055871
    reference_title: ZBTB42 mutation defines a novel lethal congenital contracture syndrome (LCCS6).
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Knockdown experiments of zbtb42 in zebrafish consistently resulted in grossly abnormal skeletal muscle development and myofibrillar disorganization at the microscopic level."
    explanation: >-
      Shows the ZBTB42 lesion is a muscle developmental and myofibrillar defect.
  - reference: PMID:25055871
    reference_title: ZBTB42 mutation defines a novel lethal congenital contracture syndrome (LCCS6).
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "which had been shown to be enriched in skeletal muscles, especially at the neuromuscular junction"
    explanation: Locates ZBTB42 expression at the neuromuscular junction.
  - reference: PMID:22610851
    reference_title: Autosomal recessive lethal congenital contractural syndrome type 4 (LCCS4) caused by a mutation in MYBPC1.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "a homozygous premature stop producing mutation in MYBPC1, encoding myosin-binding protein C, slow type"
    explanation: >-
      Identifies the sarcomeric thick-filament protein removed in LCCS4.
  downstream:
  - target: Absent Fetal Movement
    causal_link_type: DIRECT
    description: >-
      A structurally incompetent contractile apparatus cannot generate the
      contraction that drives fetal movement.
    evidence:
    - reference: PMID:25055871
      reference_title: ZBTB42 mutation defines a novel lethal congenital contracture syndrome (LCCS6).
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Lack of fetal movement across the joints that are involved in AMC can be attributed to factors that impair the contractility or innervation of skeletal muscle"
      explanation: >-
        States the contractility route to absent fetal movement that the
        muscle-side subtypes take.
- name: Endocytic Trafficking Failure
  biological_scale: CELLULAR
  subtypes:
  - LCCS5
  description: >-
    Impaired dynamin-2-dependent membrane fission and endocytosis. This is a
    separate muscle-side lesion from the myofibril one: the defect is in
    membrane trafficking rather than in the contractile apparatus, and its
    pleiotropy - dynamin-2 is required in both muscle and vascular development -
    is what gives LCCS5 the haemorrhagic findings the other subtypes lack.
  biological_processes:
  - preferred_term: endocytosis
    term:
      id: GO:0006897
      label: endocytosis
    modifier: DECREASED
  evidence:
  - reference: PMID:23092955
    reference_title: Dynamin 2 homozygous mutation in humans with a lethal congenital syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "In vitro membrane tubulation, trafficking and GTPase assays are consistent with an impact of the DNM2p.Phe379Val mutation on endocytosis."
    explanation: >-
      Functional assays localizing the DNM2 lesion to endocytosis.
  - reference: PMID:23092955
    reference_title: Dynamin 2 homozygous mutation in humans with a lethal congenital syndrome.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "knockdown approaches in zebrafish resulting in defects in muscle organization and angiogenesis support a pleiotropic role for DNM2 during fetal development in vertebrates and humans"
    explanation: >-
      Supports the pleiotropic muscle-and-vascular role that separates this node
      from the purely myofibrillar one.
  downstream:
  - target: Absent Fetal Movement
    causal_link_type: DIRECT
    description: >-
      Disordered muscle organization downstream of the trafficking defect
      prevents effective fetal contraction.
    evidence:
    - reference: PMID:23092955
      reference_title: Dynamin 2 homozygous mutation in humans with a lethal congenital syndrome.
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: MODEL_ORGANISM
      snippet: "knockdown approaches in zebrafish resulting in defects in muscle organization and angiogenesis"
      explanation: >-
        Links the DNM2 defect to disordered muscle organization. Indirect because
        the movement step itself is shown in the human phenotype rather than
        measured here.
- name: Neurogenic Skeletal Muscle Atrophy and Hypoplasia
  biological_scale: TISSUE
  subtypes:
  - LCCS1
  - LCCS2
  - LCCS3
  description: >-
    Severe hypoplasia and atrophy of skeletal muscle, most marked in the lower
    limbs, downstream of the anterior horn cell loss. In LCCS1 fetal autopsy this
    is found together with ventral spinal cord atrophy and in the absence of other
    structural organ anomalies.
  cell_types:
  - preferred_term: skeletal muscle fiber
    term:
      id: CL:0008002
      label: skeletal muscle fiber
  biological_processes:
  - preferred_term: skeletal muscle tissue development
    term:
      id: GO:0007519
      label: skeletal muscle tissue development
    modifier: DECREASED
  locations:
  - preferred_term: skeletal muscle tissue
    term:
      id: UBERON:0001134
      label: skeletal muscle tissue
  evidence:
  - reference: PMID:11810649
    reference_title: "Heterogeneity in fetal akinesia deformation sequence (FADS): autopsy confirmation in three 20-21-week fetuses."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Neuropathologic examination revealed anterior horn cell loss and lateral corticospinal tract degeneration in spinal cord, with marked muscular atrophy."
    explanation: >-
      Autopsy pairing of anterior horn cell loss with muscular atrophy in a
      fetal akinesia case.
  downstream:
  - target: Absent Fetal Movement
    causal_link_type: DIRECT
    description: >-
      Denervated, hypoplastic muscle cannot move the fetal limbs.
    evidence:
    - reference: PMID:11810649
      reference_title: "Heterogeneity in fetal akinesia deformation sequence (FADS): autopsy confirmation in three 20-21-week fetuses."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Neurogenic spinal muscular atrophy was the basis of fetal akinesia in Case 1."
      explanation: >-
        Attributes the fetal akinesia in that case directly to the neurogenic
        muscle atrophy.
- name: Absent Fetal Movement
  biological_scale: ORGANISM
  description: >-
    Total or near-total fetal akinesia, detectable on ultrasound from the late
    first or second trimester and persisting at every subsequent examination.
    This is the convergence node of the whole entry: every subtype, whatever the
    level of its primary lesion, arrives here, and everything below it is
    deformation secondary to the missing movement rather than a separate genetic
    effect.
  evidence:
  - reference: PMID:16892327
    reference_title: Lethal congenital contracture syndrome (LCCS) and other lethal arthrogryposes in Finland--an epidemiological study.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Thirty-nine cases had lethal congenital contracture syndrome (LCCS) clinically characterized by total immobility of the fetus at all ultrasound examinations (12 weeks or later)"
    explanation: >-
      Documents total fetal immobility as the defining clinical observation in a
      population-based LCCS series.
  - reference: PMID:25055871
    reference_title: ZBTB42 mutation defines a novel lethal congenital contracture syndrome (LCCS6).
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "LCCS is genetically heterogeneous with mutations in five genes identified to date, all with a role in the innervation or contractile apparatus of skeletal muscles."
    explanation: >-
      States the shared mechanistic denominator - innervation or contractile
      apparatus - that makes this a single convergence node across the subtypes.
  downstream:
  - target: Joint Contracture Formation
    causal_link_type: DIRECT
    description: >-
      Immobile joints fix in whatever position the limb is held, and the
      periarticular connective tissue consolidates around it.
    evidence:
    - reference: PMID:35806855
      reference_title: "Lethal Congenital Contracture Syndrome 11: A Case Report and Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Arthrogryposis is characterized by congenital joint contractures in two or more body areas resulting from reduced or absent fetal movements"
      explanation: >-
        States the movement-to-contracture causal step directly.
  - target: Pulmonary Hypoplasia
    causal_link_type: DIRECT
    description: >-
      Absent fetal breathing movements deprive the developing lung of the
      cyclical distension that drives its growth.
    evidence:
    - reference: PMID:35806855
      reference_title: "Lethal Congenital Contracture Syndrome 11: A Case Report and Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Once the contracture is formed, a variety of secondary deformations occur, including craniofacial changes, pulmonary hypoplasia, polyhydramnios, decreased gut mobility and shortened gut, short umbilical cord, skin changes, and multiple joints with limitation of movement."
      explanation: >-
        Lists pulmonary hypoplasia among the deformations secondary to the absent
        movement.
  - target: Impaired Swallowing
    causal_link_type: DIRECT
    description: >-
      Akinesia includes the swallowing musculature, so amniotic fluid is not
      cleared.
    evidence:
    - reference: PMID:35806855
      reference_title: "Lethal Congenital Contracture Syndrome 11: A Case Report and Literature Review."
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: HUMAN_CLINICAL
      snippet: "Once the contracture is formed, a variety of secondary deformations occur, including craniofacial changes, pulmonary hypoplasia, polyhydramnios, decreased gut mobility and shortened gut, short umbilical cord, skin changes, and multiple joints with limitation of movement."
      explanation: >-
        Places polyhydramnios and reduced gut motility among the secondary
        deformations. Indirect because the swallowing step is inferred from the
        polyhydramnios rather than measured.
- name: Joint Contracture Formation
  biological_scale: TISSUE
  description: >-
    Fixed, non-progressive contractures of multiple joints in both upper and
    lower limbs, classically extended elbows with flexed knees or the reverse.
    Because embryonic movement is required for normal joint cavitation and
    skeletal maturation, the contractures are a developmental deformation and do
    not spontaneously reverse once formed.
  locations:
  - preferred_term: limb joint
    term:
      id: UBERON:0003657
      label: limb joint
  evidence:
  - reference: PMID:26142413
    reference_title: "The importance of foetal movement for co-ordinated cartilage and bone development in utero : clinical consequences and potential for therapy."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Infants whose movement in utero is reduced or restricted and who subsequently suffer from joint dysplasia (including joint contractures) and thin hypo-mineralised bones, demonstrate that embryonic movement is crucial for appropriate skeletogenesis."
    explanation: >-
      Supplies the developmental-biology basis for treating the contractures as a
      consequence of the missing movement.
  - reference: PMID:16892327
    reference_title: Lethal congenital contracture syndrome (LCCS) and other lethal arthrogryposes in Finland--an epidemiological study.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "multiple joint contractures in both upper and lower limbs, hydrops, and fetal death before the 32nd week of pregnancy"
    explanation: Records the distribution of contractures in the LCCS series.
- name: Impaired Swallowing
  biological_scale: ORGANISM
  description: >-
    Loss of the swallowing that normally clears amniotic fluid before birth,
    producing polyhydramnios, and the same deficit persisting after birth as
    dysphagia requiring nasogastric or gastrostomy feeding. Named without
    "fetal" because the node spans both periods - the postnatal half is what
    enteral feeding targets.
  evidence:
  - reference: PMID:35806855
    reference_title: "Lethal Congenital Contracture Syndrome 11: A Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The fetus exhibited hydrops, short long bones, fixed limb joints, absent fetal movements, and polyhydramnios."
    explanation: >-
      Records polyhydramnios alongside the absent fetal movement in an LCCS11
      fetus.
- name: Pulmonary Hypoplasia
  biological_scale: ORGANISM
  description: >-
    Underdevelopment of the fetal lung secondary to absent fetal breathing
    movements and to thoracic restriction. It is the principal proximate cause of
    death in liveborn infants and the reason that respiratory support determines
    survival more than any other single factor.
  biological_processes:
  - preferred_term: lung development
    term:
      id: GO:0030324
      label: lung development
    modifier: DECREASED
  locations:
  - preferred_term: lung
    term:
      id: UBERON:0002048
      label: lung
  evidence:
  - reference: PMID:32812332
    reference_title: "The latest FADS: Functional analysis of GLDN patient variants and classification of GLDN-associated AMC as a type of viable fetal akinesia deformation sequence."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "with emphasis on the finding of pulmonary hypoplasia, suggesting that AMC secondary to GLDN variants may be best fitted under the umbrella of fetal akinesia deformation sequence (FADS)"
    explanation: >-
      Identifies pulmonary hypoplasia as the finding that places GLDN-related
      disease within the fetal akinesia deformation sequence.
  - reference: PMID:11810649
    reference_title: "Heterogeneity in fetal akinesia deformation sequence (FADS): autopsy confirmation in three 20-21-week fetuses."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Fetal akinesia deformation sequence (FADS) is a rare condition characterized by intrauterine growth retardation (IUGR), congenital limb contractures, pulmonary hypoplasia, hydramnios and craniofacial abnormalities."
    explanation: >-
      Defines the deformation sequence in which pulmonary hypoplasia sits
      alongside the contractures.
  downstream:
  - target: Neonatal Respiratory Failure
    causal_link_type: DIRECT
    description: >-
      A hypoplastic lung cannot support gas exchange after delivery.
    evidence:
    - reference: PMID:35806855
      reference_title: "Lethal Congenital Contracture Syndrome 11: A Case Report and Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "To our knowledge, among the herein 28 reviewed cases, 16 reported respiratory findings, pulmonary hypoplasia being the most frequent (75%, 12/16), followed by pulmonary insufficiency or need of respiratory support."
      explanation: >-
        In the pooled LCCS11 literature review, pulmonary hypoplasia dominates the
        respiratory findings and is followed by respiratory insufficiency,
        supporting the hypoplasia-to-failure step.
- name: Neonatal Respiratory Failure
  biological_scale: ORGANISM
  description: >-
    Respiratory insufficiency at or shortly after birth, from the combination of
    pulmonary hypoplasia, weak or absent respiratory drive, diaphragmatic
    weakness and thoracic restriction. It is the immediate cause of death in most
    liveborn infants and the intervention target in those who survive.
  evidence:
  - reference: PMID:38491417
    reference_title: Novel PIP5K1C variant identified in a Chinese pedigree with lethal congenital contractural syndrome 3.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "a rare autosomal recessive genetic disorder characterized by small gestational age, severe multiple joint contractures and muscle atrophy, early death due to respiratory failure"
    explanation: >-
      Names respiratory failure as the mode of early death in LCCS3.
  - reference: PMID:28726266
    reference_title: "Survival among children with \"Lethal\" congenital contracture syndrome 11 caused by novel mutations in the gliomedin gene (GLDN)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "He required extensive resuscitation at birth including intubation, ventilation, chest compressions, and epinephrine administration, developed progressive respiratory failure, pneumothoraces, and pulmonary hemorrhage, and died at 40 hours of age"
    explanation: >-
      A worked LCCS11 case in which progressive neonatal respiratory failure was
      the proximate cause of death.

phenotypes:
- category: Prenatal
  name: Absent Fetal Movement
  description: >-
    Total immobility of the fetus at every ultrasound examination from 12 weeks
    of gestation onwards. This is the earliest and most specific finding.
  phenotype_term:
    preferred_term: Absent fetal movement
    term:
      id: HP:0001558
      label: Decreased fetal movement
  reports_on:
  - target: Absent Fetal Movement
    relationship: READOUT_OF
    direction: NEGATIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      Serial ultrasound movement assessment is the clinical observation of the
      convergence node itself, and the earliest sign available.
  frequency: VERY_FREQUENT
  evidence:
  - reference: PMID:16892327
    reference_title: Lethal congenital contracture syndrome (LCCS) and other lethal arthrogryposes in Finland--an epidemiological study.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Thirty-nine cases had lethal congenital contracture syndrome (LCCS) clinically characterized by total immobility of the fetus at all ultrasound examinations (12 weeks or later)"
    explanation: >-
      Establishes total fetal immobility from 12 weeks as a defining clinical
      feature of LCCS in a population-based series.
- category: Musculoskeletal
  name: Multiple Congenital Joint Contractures
  description: >-
    Fixed contractures of multiple joints in both upper and lower limbs, present
    at birth and non-progressive. The classical pattern is extension at the
    elbows with flexion at the knees, though the reverse is also described.
  phenotype_term:
    preferred_term: Multiple joint contractures
    term:
      id: HP:0002828
      label: Multiple joint contractures
  reports_on:
  - target: Joint Contracture Formation
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      The examined contracture pattern is the clinical expression of the
      contracture-formation node.
  frequency: VERY_FREQUENT
  evidence:
  - reference: PMID:16892327
    reference_title: Lethal congenital contracture syndrome (LCCS) and other lethal arthrogryposes in Finland--an epidemiological study.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "multiple joint contractures in both upper and lower limbs, hydrops, and fetal death before the 32nd week of pregnancy"
    explanation: Records the contracture distribution in the LCCS cases.
- category: Respiratory
  name: Pulmonary Hypoplasia
  description: >-
    Underdeveloped lungs on prenatal imaging and at autopsy, the commonest
    respiratory finding in the pooled LCCS11 literature and the leading cause of
    neonatal death across subtypes.
  phenotype_term:
    preferred_term: Pulmonary hypoplasia
    term:
      id: HP:0002089
      label: Pulmonary hypoplasia
  reports_on:
  - target: Pulmonary Hypoplasia
    relationship: READOUT_OF
    direction: NEGATIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      Imaging and postmortem lung assessment report on the hypoplasia node
      directly.
  frequency: FREQUENT
  evidence:
  - reference: PMID:35806855
    reference_title: "Lethal Congenital Contracture Syndrome 11: A Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "To our knowledge, among the herein 28 reviewed cases, 16 reported respiratory findings, pulmonary hypoplasia being the most frequent (75%, 12/16), followed by pulmonary insufficiency or need of respiratory support."
    explanation: >-
      Quantifies pulmonary hypoplasia as the dominant respiratory finding across
      reviewed LCCS11 cases.
- category: Respiratory
  name: Neonatal Respiratory Failure
  description: >-
    Respiratory insufficiency at or shortly after birth, requiring intubation and
    mechanical ventilation, and usually fatal without sustained intensive support.
  phenotype_term:
    preferred_term: Respiratory failure
    term:
      id: HP:0002878
      label: Respiratory failure
  reports_on:
  - target: Neonatal Respiratory Failure
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      Postnatal gas exchange and ventilatory requirement report on the
      respiratory-failure node.
  frequency: FREQUENT
  evidence:
  - reference: PMID:38491417
    reference_title: Novel PIP5K1C variant identified in a Chinese pedigree with lethal congenital contractural syndrome 3.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Then, she underwent vaginal delivery prematurely at 26 weeks, and the baby passed away after birth due to respiratory failure."
    explanation: Documents neonatal death from respiratory failure in an LCCS3 case.
- category: Prenatal
  name: Polyhydramnios
  description: >-
    Excess amniotic fluid from impaired fetal swallowing, and often the finding
    that brings the pregnancy to attention.
  phenotype_term:
    preferred_term: Polyhydramnios
    term:
      id: HP:0001561
      label: Polyhydramnios
  reports_on:
  - target: Impaired Swallowing
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      Amniotic fluid volume is the indirect readout of fetal swallowing, which
      is not itself directly observable.
  frequency: FREQUENT
  evidence:
  - reference: PMID:35806855
    reference_title: "Lethal Congenital Contracture Syndrome 11: A Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The fetus exhibited hydrops, short long bones, fixed limb joints, absent fetal movements, and polyhydramnios."
    explanation: Records polyhydramnios in an LCCS11 fetus.
- category: Prenatal
  name: Hydrops Fetalis
  subtype: LCCS1
  description: >-
    Generalized fetal oedema, characteristic of LCCS1 and reported in some
    LCCS11 fetuses, but explicitly absent in LCCS2 and LCCS3 - one of the few
    features that discriminates between subtypes prenatally.
  phenotype_term:
    preferred_term: Hydrops fetalis
    term:
      id: HP:0001789
      label: Hydrops fetalis
  frequency: FREQUENT
  evidence:
  - reference: PMID:16892327
    reference_title: Lethal congenital contracture syndrome (LCCS) and other lethal arthrogryposes in Finland--an epidemiological study.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "multiple joint contractures in both upper and lower limbs, hydrops, and fetal death before the 32nd week of pregnancy"
    explanation: >-
      Lists hydrops among the defining features of the Finnish LCCS (LCCS1) cases.
  - reference: PMID:18204449
    reference_title: Mutations in mRNA export mediator GLE1 result in a fetal motoneuron disease.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "accompanied by hydrops, micrognatia, pulmonary hypoplasia, pterygia and multiple joint contractures"
    explanation: Confirms hydrops as a characteristic LCCS1 feature.
- category: Craniofacial
  name: Micrognathia
  description: >-
    Small or retruded mandible, a deformation consequence of absent fetal jaw
    movement and part of the akinesia deformation sequence.
  phenotype_term:
    preferred_term: Micrognathia
    term:
      id: HP:0000347
      label: Micrognathia
  frequency: FREQUENT
  evidence:
  - reference: PMID:18204449
    reference_title: Mutations in mRNA export mediator GLE1 result in a fetal motoneuron disease.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "accompanied by hydrops, micrognatia, pulmonary hypoplasia, pterygia and multiple joint contractures"
    explanation: >-
      Lists micrognathia among the characteristic LCCS1 features. The source
      spells it "micrognatia"; the quote preserves the source spelling.
  - reference: PMID:35806855
    reference_title: "Lethal Congenital Contracture Syndrome 11: A Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "confirming the prenatal diagnosis and expanding the associated phenotype spectrum with pulmonary hypoplasia, retrognathia, and clubfoot"
    explanation: >-
      Confirms the same jaw finding (as retrognathia) in the LCCS11 postmortem
      series, showing it is not confined to LCCS1.
- category: Growth
  name: Intrauterine Growth Restriction
  description: >-
    Fetal growth restriction, present in the akinesia deformation sequence and
    confirmed at postmortem examination in LCCS11.
  phenotype_term:
    preferred_term: Intrauterine growth retardation
    term:
      id: HP:0001511
      label: Intrauterine growth retardation
  frequency: FREQUENT
  evidence:
  - reference: PMID:35806855
    reference_title: "Lethal Congenital Contracture Syndrome 11: A Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "postmortem studies confirmed the prenatal findings: distal arthrogryposis, fetal growth restriction, pulmonary hypoplasia, and retrognathia"
    explanation: Postmortem confirmation of fetal growth restriction in LCCS11.
- category: Musculoskeletal
  name: Skeletal Muscle Atrophy
  description: >-
    Marked atrophy and hypoplasia of skeletal muscle, most pronounced in the
    lower limbs, found at fetal autopsy together with anterior horn cell loss.
  phenotype_term:
    preferred_term: Skeletal muscle atrophy
    term:
      id: HP:0003202
      label: Skeletal muscle atrophy
  reports_on:
  - target: Neurogenic Skeletal Muscle Atrophy and Hypoplasia
    relationship: READOUT_OF
    direction: NEGATIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      Muscle bulk at autopsy or on imaging reports on the muscle hypoplasia
      node.
  frequency: VERY_FREQUENT
  evidence:
  - reference: PMID:18204449
    reference_title: Mutations in mRNA export mediator GLE1 result in a fetal motoneuron disease.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Neuropathological analysis shows lack of anterior horn motoneurons, severe atrophy of the ventral spinal cord and hypoplastic, nearly absent skeletal muscles"
    explanation: >-
      LCCS1-specific neuropathology pairing the anterior horn cell loss with
      nearly absent skeletal muscle.
  - reference: PMID:11810649
    reference_title: "Heterogeneity in fetal akinesia deformation sequence (FADS): autopsy confirmation in three 20-21-week fetuses."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: "Neuropathologic examination revealed anterior horn cell loss and lateral corticospinal tract degeneration in spinal cord, with marked muscular atrophy."
    explanation: >-
      The same pairing in an un-genotyped fetal akinesia case. Indirect because
      the fetus was not molecularly diagnosed as LCCS.
- category: Musculoskeletal
  name: Pterygia
  subtype: LCCS1
  description: >-
    Webbing across flexed joints, characteristic of LCCS1 and explicitly absent
    in LCCS2 and LCCS3.
  phenotype_term:
    preferred_term: Pterygium
    term:
      id: HP:0001059
      label: Pterygium
  frequency: FREQUENT
  evidence:
  - reference: PMID:18204449
    reference_title: Mutations in mRNA export mediator GLE1 result in a fetal motoneuron disease.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lethal congenital contracture syndrome 1 (LCCS1, MIM 253310) is an autosomal recessive condition characterized by total immobility of the fetus, detectable at the 13th week of pregnancy, accompanied by hydrops, micrognatia, pulmonary hypoplasia, pterygia and multiple joint contractures"
    explanation: >-
      Lists pterygia among the characteristic features of LCCS1 specifically,
      which is the subtype this phenotype is tagged to.
- category: Neurologic
  name: Reduced Motor Nerve Conduction Velocity
  subtype: LCCS7
  description: >-
    Motor nerve conduction velocity below 10 m/s in the axoglial subtypes -
    the electrophysiological signature that distinguishes a nodopathic or
    demyelinating LCCS from an anterior horn cell one in a liveborn infant.
  phenotype_term:
    preferred_term: Decreased motor nerve conduction velocity
    term:
      id: HP:0003431
      label: Decreased motor nerve conduction velocity
  frequency: VERY_FREQUENT
  reports_on:
  - target: Impaired Motor Nerve Conduction
    relationship: READOUT_OF
    direction: NEGATIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      Nerve conduction study velocity is the bedside readout of the axoglial
      conduction failure node; velocities below 10 m/s indicate a nodopathic or
      demyelinating rather than an anterior horn cell lesion.
  evidence:
  - reference: PMID:24319099
    reference_title: Mutations in CNTNAP1 and ADCY6 are responsible for severe arthrogryposis multiplex congenita with axoglial defects.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Patients showed a marked reduction in motor nerve conduction velocity (<10 m/s)"
    explanation: >-
      Reports the measured conduction velocities in CNTNAP1-mutated patients.
- category: Genitourinary
  name: Neurogenic Bladder
  subtype: LCCS2
  description: >-
    A markedly distended urinary bladder - fetal megacystis on ultrasound -
    reflecting neurogenic bladder dysfunction. It is the feature that
    distinguishes LCCS2 from the otherwise clinically identical LCCS3. Bound to
    the functional term HP:0000011 rather than to HP:0010956 Fetal megacystis
    because both LCCS2 and LCCS3 sources describe it functionally, as a
    neurogenic bladder.
  phenotype_term:
    preferred_term: Neurogenic bladder
    term:
      id: HP:0000011
      label: Neurogenic bladder
  frequency: VERY_FREQUENT
  evidence:
  - reference: PMID:17701904
    reference_title: "Lethal congenital contractural syndrome type 2 (LCCS2) is caused by a mutation in ERBB3 (Her3), a modulator of the phosphatidylinositol-3-kinase/Akt pathway."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "is characterized by multiple joint contractures, anterior horn atrophy in the spinal cord, and a unique feature of a markedly distended urinary bladder"
    explanation: >-
      The positive LCCS2 statement, naming the distended bladder as the unique
      feature of that subtype.
  - reference: PMID:17701898
    reference_title: "Lethal contractural syndrome type 3 (LCCS3) is caused by a mutation in PIP5K1C, which encodes PIPKI gamma of the phophatidylinsitol pathway."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We now describe a third LCCS phenotype (LCCS3)--similar to LCCS2 yet without neurogenic bladder."
    explanation: >-
      The complementary negative, confirming the finding discriminates LCCS2 from
      LCCS3.
- category: Neurologic
  name: Intracranial Hemorrhage
  subtype: LCCS5
  description: >-
    Brain haemorrhage, reported in the DNM2-related subtype and not a general
    feature of the group.
  phenotype_term:
    preferred_term: Intracranial hemorrhage
    term:
      id: HP:0002170
      label: Intracranial hemorrhage
  frequency: VERY_FREQUENT
  evidence:
  - reference: PMID:23092955
    reference_title: Dynamin 2 homozygous mutation in humans with a lethal congenital syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "in three consanguineous patients with a lethal congenital syndrome associating akinesia, joint contractures, hypotonia, skeletal abnormalities, and brain and retinal hemorrhages"
    explanation: >-
      Reports the intracranial haemorrhage that helps define the DNM2 subtype.
- category: Ophthalmologic
  name: Retinal Hemorrhage
  subtype: LCCS5
  description: >-
    Retinal haemorrhage accompanying the intracranial bleeding in the DNM2
    subtype. Curated separately from the intracranial finding so each is
    independently queryable.
  phenotype_term:
    preferred_term: Retinal hemorrhage
    term:
      id: HP:0000573
      label: Retinal hemorrhage
  frequency: VERY_FREQUENT
  evidence:
  - reference: PMID:23092955
    reference_title: Dynamin 2 homozygous mutation in humans with a lethal congenital syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "in three consanguineous patients with a lethal congenital syndrome associating akinesia, joint contractures, hypotonia, skeletal abnormalities, and brain and retinal hemorrhages"
    explanation: Reports retinal haemorrhage in the DNM2-mutated patients.
- category: Musculoskeletal
  name: Talipes Equinovarus
  description: >-
    Bilateral club foot, one of the earliest structural findings on prenatal
    ultrasound and often the observation that prompts investigation before the
    full contracture pattern is apparent.
  phenotype_term:
    preferred_term: Talipes equinovarus
    term:
      id: HP:0001762
      label: Talipes equinovarus
  frequency: FREQUENT
  evidence:
  - reference: PMID:38491417
    reference_title: Novel PIP5K1C variant identified in a Chinese pedigree with lethal congenital contractural syndrome 3.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We described the features of multiple joint contractures in our fetuses, including bilateral talipes equinovarus, stiffness in the limbs, extended knees, persistently closed hands and overlapping fingers"
    explanation: >-
      Documents bilateral talipes equinovarus as part of the contracture pattern
      in LCCS3 fetuses.
  - reference: PMID:35806855
    reference_title: "Lethal Congenital Contracture Syndrome 11: A Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "confirming the prenatal diagnosis and expanding the associated phenotype spectrum with pulmonary hypoplasia, retrognathia, and clubfoot"
    explanation: >-
      Confirms clubfoot in the pooled LCCS11 postmortem series, showing the
      finding is not restricted to one subtype.
- category: Neurologic
  name: Areflexia
  description: >-
    Absent or very weak deep tendon reflexes, expected in the axoglial subtypes
    where the reflex arc is interrupted by the conduction failure. It is the
    bedside sign that points away from a purely muscular cause.
  phenotype_term:
    preferred_term: Areflexia
    term:
      id: HP:0001284
      label: Areflexia
  evidence:
  - reference: PMID:28726266
    reference_title: "Survival among children with \"Lethal\" congenital contracture syndrome 11 caused by novel mutations in the gliomedin gene (GLDN)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "His neurologic examination was notable for myopathic facies, very weak to absent deep tendon reflexes, and symmetric atrophy and weakness of his proximal muscles."
    explanation: >-
      Documents absent deep tendon reflexes on examination in a GLDN-mutated
      child.
- category: Gastrointestinal
  name: Dysphagia
  description: >-
    Insufficient swallowing persisting after birth, the postnatal continuation of
    the same akinesia that produced the polyhydramnios. It drives aspiration risk
    and is the indication for gastrostomy feeding in survivors.
  phenotype_term:
    preferred_term: Dysphagia
    term:
      id: HP:0002015
      label: Dysphagia
  evidence:
  - reference: PMID:28726266
    reference_title: "Survival among children with \"Lethal\" congenital contracture syndrome 11 caused by novel mutations in the gliomedin gene (GLDN)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Insufficient swallowing aggravated by paresis of both the right vocal cord and right side of the soft palate prompted gastrostomy tube placement at 4 months of age."
    explanation: >-
      Documents insufficient swallowing and the gastrostomy it required in a
      surviving LCCS11 child.
- category: Musculoskeletal
  name: Overlapping Fingers
  subtype: LCCS3
  description: >-
    Persistently closed hands with overlapping fingers, part of the fixed hand
    posture that accompanies the limb contractures.
  phenotype_term:
    preferred_term: Overlapping fingers
    term:
      id: HP:0010557
      label: Overlapping fingers
  evidence:
  - reference: PMID:38491417
    reference_title: Novel PIP5K1C variant identified in a Chinese pedigree with lethal congenital contractural syndrome 3.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "including bilateral talipes equinovarus, stiffness in the limbs, extended knees, persistently closed hands and overlapping fingers"
    explanation: >-
      Documents the closed-hand and overlapping-finger posture in LCCS3 fetuses.
- category: Respiratory
  name: Vocal Cord Paresis
  subtype: LCCS11
  description: >-
    Vocal cord paresis reported in a surviving GLDN-mutated child, contributing
    to the swallowing failure and aspiration risk alongside the more general
    akinesia.
  phenotype_term:
    preferred_term: Vocal cord paresis
    term:
      id: HP:0001604
      label: Vocal cord paresis
  evidence:
  - reference: PMID:28726266
    reference_title: "Survival among children with \"Lethal\" congenital contracture syndrome 11 caused by novel mutations in the gliomedin gene (GLDN)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Insufficient swallowing aggravated by paresis of both the right vocal cord and right side of the soft palate prompted gastrostomy tube placement at 4 months of age."
    explanation: >-
      Documents vocal cord paresis and its contribution to the swallowing
      failure.
- category: Neurologic
  name: Severe Hypotonia
  description: >-
    Profound generalized hypotonia in liveborn infants. Reported directly in the
    DNM2 series; areflexia is curated separately because it is the more
    discriminating sign in the axoglial subtypes.
  phenotype_term:
    preferred_term: Generalized hypotonia
    term:
      id: HP:0001290
      label: Generalized hypotonia
  frequency: FREQUENT
  evidence:
  - reference: PMID:23092955
    reference_title: Dynamin 2 homozygous mutation in humans with a lethal congenital syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "a lethal congenital syndrome associating akinesia, joint contractures, hypotonia, skeletal abnormalities, and brain and retinal hemorrhages"
    explanation: Lists hypotonia among the presenting features.

genetic:
- name: GLE1
  subtype: LCCS1
  gene_term:
    preferred_term: GLE1
    term:
      id: hgnc:4315
      label: GLE1
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  presence: PRESENT
  notes: >-
    GLE1 mediates nuclear mRNA export and regulates translation initiation and
    termination. Allelic GLE1 disease spans a severity spectrum: alleles that
    abolish coiled-coil domain function give lethal LCCS1, while alleles that
    preserve it give the milder LAAHD/AAHD phenotype with survival past the
    perinatal period.
  evidence:
  - reference: PMID:18204449
    reference_title: Mutations in mRNA export mediator GLE1 result in a fetal motoneuron disease.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Our finding of mutated GLE1 exposes a common pathway connecting the genes implicated in LCCS1, LCCS2 and LCCS3 and elucidates mRNA processing as a critical molecular mechanism in motoneuron development and maturation."
    explanation: >-
      Establishes GLE1 as the LCCS1 gene and proposes the shared pathway with the
      LCCS2 and LCCS3 genes.
  - reference: PMID:28884921
    reference_title: Survival beyond the perinatal period expands the phenotypes caused by mutations in GLE1.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We hypothesize that mutations that preserve function of the coiled-coil domain of GLE1 cause LAAHD whereas mutations that abolish the function of the coiled-coil domain cause LCCS."
    explanation: >-
      Records the proposed genotype-severity relationship within the GLE1 allelic
      series.
- name: ERBB3
  subtype: LCCS2
  gene_term:
    preferred_term: ERBB3
    term:
      id: hgnc:3431
      label: ERBB3
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  presence: PRESENT
  notes: >-
    First reported human phenotype caused by loss of function in an EGF-family
    receptor tyrosine kinase; the same family's gain-of-function alleles cause
    cancer predisposition.
  evidence:
  - reference: PMID:17701904
    reference_title: "Lethal congenital contractural syndrome type 2 (LCCS2) is caused by a mutation in ERBB3 (Her3), a modulator of the phosphatidylinositol-3-kinase/Akt pathway."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "This is the first report of a human phenotype resulting from loss of function of a member of this group."
    explanation: >-
      Records the loss-of-function mechanism and its novelty within the receptor
      family.
- name: PIP5K1C
  subtype: LCCS3
  gene_term:
    preferred_term: PIP5K1C
    term:
      id: hgnc:8996
      label: PIP5K1C
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  presence: PRESENT
  evidence:
  - reference: PMID:17701898
    reference_title: "Lethal contractural syndrome type 3 (LCCS3) is caused by a mutation in PIP5K1C, which encodes PIPKI gamma of the phophatidylinsitol pathway."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We demonstrate that the mutation causes substitution of aspartic acid with asparagine at amino acid 253 (D253N), abrogating the kinase activity of PIPKI gamma"
    explanation: >-
      Gives the founder allele and its demonstrated effect on kinase activity.
  - reference: PMID:38491417
    reference_title: Novel PIP5K1C variant identified in a Chinese pedigree with lethal congenital contractural syndrome 3.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "These findings expanded the genetic variant spectrum of PIP5K1C and enriched the clinical features of LCCS3"
    explanation: >-
      Extends the PIP5K1C allelic spectrum beyond the original Bedouin founder
      variant.
- name: MYBPC1
  subtype: LCCS4
  gene_term:
    preferred_term: MYBPC1
    term:
      id: hgnc:7549
      label: MYBPC1
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  presence: PRESENT
  notes: >-
    Dose- and mechanism-dependent: dominant missense alleles give distal
    arthrogryposis, recessive truncating alleles give lethal disease.
  evidence:
  - reference: PMID:22610851
    reference_title: Autosomal recessive lethal congenital contractural syndrome type 4 (LCCS4) caused by a mutation in MYBPC1.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A dominant missense mutation in MYBPC1 was previously shown to cause mild distal arthrogryposis."
    explanation: >-
      Contrasts the dominant missense and recessive truncating mechanisms in the
      same gene.
  - reference: PMID:26661508
    reference_title: "Expanding the MYBPC1 phenotypic spectrum: a novel homozygous mutation causes arthrogryposis multiplex congenita."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Heterozygous mutations in this gene are associated with distal arthrogryposis types 1b and 2, whereas a homozygous nonsense mutation is implicated in one family with lethal congenital contractural syndrome 4."
    explanation: >-
      Sets out the MYBPC1 allelic series, and notes that the lethal LCCS4 end of
      it rests on a single reported family.
- name: DNM2
  subtype: LCCS5
  gene_term:
    preferred_term: DNM2
    term:
      id: hgnc:2974
      label: DNM2
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  presence: PRESENT
  notes: >-
    Heterozygous DNM2 alleles cause dominant Charcot-Marie-Tooth neuropathy and
    centronuclear myopathy; the homozygous p.Phe379Val allele causes this far more
    severe fetal phenotype.
  evidence:
  - reference: PMID:23092955
    reference_title: Dynamin 2 homozygous mutation in humans with a lethal congenital syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "In vitro membrane tubulation, trafficking and GTPase assays are consistent with an impact of the DNM2p.Phe379Val mutation on endocytosis."
    explanation: >-
      Functional assays supporting an endocytic defect as the DNM2 mechanism.
- name: ZBTB42
  subtype: LCCS6
  gene_term:
    preferred_term: ZBTB42
    term:
      id: hgnc:32550
      label: ZBTB42
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  presence: PRESENT
  evidence:
  - reference: PMID:25055871
    reference_title: ZBTB42 mutation defines a novel lethal congenital contracture syndrome (LCCS6).
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "This severe muscular phenotype is successfully rescued with overexpression of the human wild-type ZBTB42 gene, but not with the mutant form of ZBTB42 that models the human missense change."
    explanation: >-
      Allele-specific rescue in zebrafish establishing pathogenicity of the human
      missense change.
- name: CNTNAP1
  subtype: LCCS7
  gene_term:
    preferred_term: CNTNAP1
    term:
      id: hgnc:8011
      label: CNTNAP1
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  presence: PRESENT
  evidence:
  - reference: PMID:24319099
    reference_title: Mutations in CNTNAP1 and ADCY6 are responsible for severe arthrogryposis multiplex congenita with axoglial defects.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Homozygous frameshift mutations in CNTNAP1 were found in four unrelated families."
    explanation: Multi-family evidence for biallelic CNTNAP1 loss of function.
  - reference: PMID:29882456
    reference_title: "Absence of Axoglial Paranodal Junctions in a Child With CNTNAP1 Mutations, Hypomyelination, and Arthrogryposis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "By ultrastructural evaluation, septate axoglial paranodal junctions were absent from nodes of Ranvier."
    explanation: >-
      Ultrastructural confirmation in human nerve that CNTNAP1 loss removes the
      paranodal junction, the lesion this subtype's mechanism claims.
- name: ADCY6
  subtype: LCCS8
  gene_term:
    preferred_term: ADCY6
    term:
      id: hgnc:237
      label: ADCY6
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  presence: PRESENT
  evidence:
  - reference: PMID:31846058
    reference_title: Expanding the clinical and molecular spectrum of lethal congenital contracture syndrome 8 associated with biallelic variants of ADCY6.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ADCY6 inactivation, due to biallelic variants, have been previously associated with the lethal congenital contracture syndrome 8 (LCCS8)."
    explanation: Confirms biallelic ADCY6 inactivation as the LCCS8 mechanism.
- name: ADGRG6
  subtype: LCCS9
  gene_term:
    preferred_term: ADGRG6
    term:
      id: hgnc:13841
      label: ADGRG6
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  presence: PRESENT
  notes: >-
    Reported under the earlier gene symbol GPR126. Autoproteolytic cleavage is
    required for receptor activation, and the reported missense allele impairs it.
  evidence:
  - reference: PMID:26004201
    reference_title: Mutations of GPR126 are responsible for severe arthrogryposis multiplex congenita.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Previous work has suggested that autoproteolytic cleavage is important for activating GPR126 signaling"
    explanation: >-
      Establishes that autoproteolytic cleavage is the activating step, the
      background against which the patient allele's cleavage defect is read. The
      paper's own assay result is quoted separately below.
  - reference: PMID:26004201
    reference_title: Mutations of GPR126 are responsible for severe arthrogryposis multiplex congenita.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "impairs autoproteolytic cleavage of GPR126"
    explanation: >-
      The paper's own biochemical result, showing the patient missense allele
      blocks the activating cleavage step.
- name: NEK9
  subtype: LCCS10
  gene_term:
    preferred_term: NEK9
    term:
      id: hgnc:18591
      label: NEK9
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  presence: PRESENT
  evidence:
  - reference: PMID:36712877
    reference_title: "Novel variants of NEK9 associated with neonatal arthrogryposis: Two case reports and a literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Pathogenic variants in NEK9 (MIM: 609798) have been identified in patients with lethal congenital contracture syndrome 10 (OMIM: 617022)"
    explanation: Establishes NEK9 as the LCCS10 gene.
- name: GLDN
  subtype: LCCS11
  gene_term:
    preferred_term: GLDN
    term:
      id: hgnc:29514
      label: GLDN
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  presence: PRESENT
  evidence:
  - reference: PMID:27616481
    reference_title: "Mutations in GLDN, Encoding Gliomedin, a Critical Component of the Nodes of Ranvier, Are Responsible for Lethal Arthrogryposis."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "The GLDN mutations found in the affected individuals abolish the cell surface localization of gliomedin and its interaction with its axonal partner, neurofascin-186 (NF186), in a cell-based assay."
    explanation: >-
      Cell-based functional evidence for the loss-of-function mechanism.
  - reference: PMID:32812332
    reference_title: "The latest FADS: Functional analysis of GLDN patient variants and classification of GLDN-associated AMC as a type of viable fetal akinesia deformation sequence."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Here, we describe one additional patient currently living with the syndrome, having one novel variant, p.Leu365Phe, for which we provide functional data supporting its pathogenicity."
    explanation: >-
      Adds functional support for a further GLDN allele in a surviving patient.
- name: DST
  subtype: LCCS12
  gene_term:
    preferred_term: DST
    term:
      id: hgnc:1090
      label: DST
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  presence: PRESENT
  notes: >-
    Isoform-dependent severity: variants restricted to DST-b give a congenital
    myopathy, while variants that also affect DST-a give the lethal congenital
    contracture phenotype. MONDO:0981031 carried no gene edge at the time of
    curation, so this binding is taken from the primary report.
  evidence:
  - reference: PMID:40497796
    reference_title: "Deciphering DST-associated disorders: biallelic variants affecting DST-b cause a congenital myopathy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Variants that also impact DST-a besides DST-b result in a more severe, lethal congenital contracture syndrome."
    explanation: >-
      Establishes DST as causative and gives the isoform-severity relationship.

diagnosis:
- name: Prenatal ultrasound
  description: >-
    Serial expert ultrasound assessing fetal movement, limb position, amniotic
    fluid volume, hydrops, growth and thoracic development. Absent movement at
    every examination from about 12 weeks is the earliest and most specific
    finding, and club foot or fixed joints are the usual first structural clue.
  presence: PRESENT
  evidence:
  - reference: PMID:35806855
    reference_title: "Lethal Congenital Contracture Syndrome 11: A Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Prenatal ultrasound imaging is crucial in its early diagnosis by identifying fetal movement limitations and the presence of club foot or joint contractures"
    explanation: States the role and yield of prenatal ultrasound.
- name: Trio exome or genome sequencing
  description: >-
    Broad sequencing rather than sequential single-gene testing, because the
    subtypes are clinically near-indistinguishable and the gene list is long and
    still growing. Diagnostic yield in arthrogryposis cohorts reaches about 60%
    with whole-exome sequencing.
  presence: PRESENT
  evidence:
  - reference: PMID:35806855
    reference_title: "Lethal Congenital Contracture Syndrome 11: A Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The diagnosis rates of arthrogryposis improve up to 60% when whole-exome sequencing (WES) is used"
    explanation: Quantifies the diagnostic yield of exome sequencing.
  - reference: PMID:26578207
    reference_title: Next generation sequencing in a large cohort of patients presenting with neuromuscular disease before or at birth.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A conclusive genetic diagnosis was achieved for 18 of the 38 families."
    explanation: >-
      Cohort-level yield of next-generation sequencing in fetal akinesia and
      arthrogryposis families.
- name: Nerve conduction study
  description: >-
    Motor nerve conduction velocity separates the axoglial subtypes (LCCS7,
    LCCS8, LCCS9, LCCS11), where it falls below 10 m/s, from the anterior horn
    cell and muscle subtypes, where the primary lesion lies elsewhere.
  presence: PRESENT
  evidence:
  - reference: PMID:24319099
    reference_title: Mutations in CNTNAP1 and ADCY6 are responsible for severe arthrogryposis multiplex congenita with axoglial defects.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Patients showed a marked reduction in motor nerve conduction velocity (<10 m/s)"
    explanation: Gives the discriminating conduction velocity threshold.
- name: Fetal and neonatal autopsy
  description: >-
    Postmortem neuropathology remains the way the anterior horn cell subtypes are
    distinguished from the peripheral nerve and muscle subtypes when sequencing is
    uninformative, and it confirms the prenatal imaging findings.
  presence: PRESENT
  evidence:
  - reference: PMID:35806855
    reference_title: "Lethal Congenital Contracture Syndrome 11: A Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "postmortem studies confirmed the prenatal findings: distal arthrogryposis, fetal growth restriction, pulmonary hypoplasia, and retrognathia"
    explanation: Shows postmortem confirmation of the prenatal findings.

differential_diagnoses:
- name: Lethal Arthrogryposis with Anterior Horn Cell Disease
  description: >-
    LAAHD (MONDO:0012750) is allelic with LCCS1 - same gene, same fetal akinesia,
    same anterior horn cell disease - and is separated only by severity and by
    survival to the perinatal rather than the fetal period. It is the single most
    important differential for LCCS1, and the proposed discriminator is
    molecular: alleles preserving GLE1 coiled-coil function give LAAHD, alleles
    abolishing it give LCCS1. Cases surviving into childhood have prompted the
    argument that "lethal" should be dropped from the LAAHD name too.
  evidence:
  - reference: PMID:28884921
    reference_title: Survival beyond the perinatal period expands the phenotypes caused by mutations in GLE1.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Both LCCS and LAAHD are characterized by reduced fetal movements, congenital contractures, and a severe form of motor neuron disease that results in fetal death or death in the perinatal period, respectively."
    explanation: >-
      States the shared phenotype and the timing difference that is the whole
      basis of the distinction.
  - reference: PMID:28884921
    reference_title: Survival beyond the perinatal period expands the phenotypes caused by mutations in GLE1.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The phenotype of LAAHD is now expanded to include multiple individuals surviving into childhood suggesting that LAAHD is a misnomer and should be re-named Arthrogryposis with Anterior Horn Cell Disease (AAHD)."
    explanation: >-
      Documents the survival that undermines the "lethal" label on the allelic
      disorder as well as on this one.
- name: Arthrogryposis Multiplex Congenita
  description: >-
    The parent clinical phenotype. AMC is the descriptive finding of congenital
    contractures in two or more body regions and covers more than 400 conditions
    and over 220 genes; LCCS is the lethal, prenatal-onset, autosomal recessive
    subset of it. Distinguishing them is a matter of severity, timing and
    molecular diagnosis rather than of contracture pattern.
  evidence:
  - reference: PMID:28726266
    reference_title: "Survival among children with \"Lethal\" congenital contracture syndrome 11 caused by novel mutations in the gliomedin gene (GLDN)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "AMC results from diverse mechanisms, including any condition that decreases or limits fetal movements."
    explanation: >-
      States the breadth of AMC against which LCCS must be positioned.
- name: KIF21A-related fetal akinesia
  description: >-
    Biallelic KIF21A loss of function causes severe fetal akinesia with
    arthrogryposis multiplex and pulmonary hypoplasia. It is clinically within the
    LCCS spectrum but is not currently a numbered LCCS subtype, and it is a
    reminder that the fetal akinesia gene list is still open.
  evidence:
  - reference: PMID:34740919
    reference_title: Bi-allelic loss-of-function variants in KIF21A cause severe fetal akinesia with arthrogryposis multiplex.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Fetal akinesia (FA) results in variable clinical presentations and has been associated with more than 166 different disease loci."
    explanation: >-
      Records the breadth of the fetal akinesia locus list that the differential
      must span.
- name: Non-genetic fetal akinesia
  description: >-
    Fetal akinesia can also result from maternal antibody-mediated disease,
    oligohydramnios, uterine constraint, teratogen exposure or congenital
    infection. Normal karyotype and microarray in an affected fetus do not exclude
    LCCS, so these must be excluded clinically rather than cytogenetically.
  evidence:
  - reference: PMID:11810649
    reference_title: "Heterogeneity in fetal akinesia deformation sequence (FADS): autopsy confirmation in three 20-21-week fetuses."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The etiology of akinesia was undetermined in Case 3; no extrinsic or intrinsic cause was identified."
    explanation: >-
      Illustrates that fetal akinesia cases can lack any identifiable intrinsic
      cause, which is what the differential is guarding against.

treatments:
- name: Mechanical Ventilation and Chronic Respiratory Support
  therapeutic_modality: DEVICE
  description: >-
    Intubation and mechanical ventilation at birth, progressing where survival is
    achieved to tracheostomy and long-term ventilation with airway clearance. This
    is the intervention that separates the reported LCCS11 and LCCS8 survivors
    from the majority who die in the neonatal period, and it modifies outcome
    without touching the underlying mechanism.
  treatment_term:
    preferred_term: Invasive Mechanical Ventilation
    term:
      id: NCIT:C191573
      label: Invasive Mechanical Ventilation
  target_mechanisms:
  - target: Neonatal Respiratory Failure
    description: >-
      Substitutes for the respiratory effort that the hypoplastic lung and weak
      respiratory musculature cannot generate.
    evidence:
    - reference: PMID:28726266
      reference_title: "Survival among children with \"Lethal\" congenital contracture syndrome 11 caused by novel mutations in the gliomedin gene (GLDN)."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Our findings confirm the association of GLDN mutations with AMC and extend the LCCS11 phenotype by describing long-term survival with chronic respiratory and nutritional support."
      explanation: >-
        Documents that chronic respiratory support is what converts a nominally
        lethal phenotype into long-term survival.
  evidence:
  - reference: PMID:28726266
    reference_title: "Survival among children with \"Lethal\" congenital contracture syndrome 11 caused by novel mutations in the gliomedin gene (GLDN)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "four of whom survived beyond the neonatal period into infancy, childhood, and late adolescence with intensive care and chronic respiratory and nutritional support"
    explanation: Reports the survival achieved with sustained respiratory support.
- name: Enteral Nutritional Support
  therapeutic_modality: DEVICE
  description: >-
    Nasogastric or gastrostomy feeding for the dysphagia that follows the same
    akinesia responsible for the polyhydramnios. Required indefinitely in
    survivors. Tagged DEVICE rather than BEHAVIORAL because gastrostomy feeding
    is a procedure delivered through an indwelling tube, not a dietary or
    lifestyle change.
  treatment_term:
    preferred_term: Enteral Tube Feeding
    term:
      id: NCIT:C93322
      label: Enteral Tube Feeding
  target_mechanisms:
  - target: Impaired Swallowing
    description: >-
      Bypasses the persistent swallowing deficit that survives into postnatal
      life.
    evidence:
    - reference: PMID:28726266
      reference_title: "Survival among children with \"Lethal\" congenital contracture syndrome 11 caused by novel mutations in the gliomedin gene (GLDN)."
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: HUMAN_CLINICAL
      snippet: "chronic respiratory and nutritional support"
      explanation: >-
        Names nutritional support as part of the survival regimen. Indirect because
        the sentence does not itself trace it to the swallowing deficit.
  evidence:
  - reference: PMID:28726266
    reference_title: "Survival among children with \"Lethal\" congenital contracture syndrome 11 caused by novel mutations in the gliomedin gene (GLDN)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "extend the LCCS11 phenotype by describing long-term survival with chronic respiratory and nutritional support"
    explanation: Documents chronic nutritional support in the surviving cohort.
- name: Genetic Counseling and Prenatal Testing
  description: >-
    Because every established locus is autosomal recessive, molecular diagnosis in
    a proband converts a recurrence risk stated as "unknown" into a 25% figure and
    makes targeted prenatal or preimplantation testing possible in subsequent
    pregnancies. In a disease with no disease-modifying therapy this is the
    principal actionable consequence of making the diagnosis.
  treatment_term:
    preferred_term: Genetic Counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
  evidence:
  - reference: PMID:29959180
    reference_title: Genetics of neuromuscular fetal akinesia in the genomics era.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A genetic diagnosis has clinical utility as it may affect management and prognosis and informs recurrence risk, facilitating family planning decisions."
    explanation: >-
      States the counselling and reproductive value of reaching a molecular
      diagnosis.
- name: Palliative and Supportive Care
  description: >-
    Multidisciplinary supportive care spanning respiratory support, nutrition,
    mobility and psychological support for the family, with palliative-care
    involvement where the presentation is uniformly severe. In a condition with
    no disease-modifying therapy for any subtype this is not an adjunct to
    treatment - it is the treatment, and the decision to escalate to
    tracheostomy and long-term ventilation or to move to comfort care is the
    substantive clinical choice families face.
  treatment_term:
    preferred_term: Palliative Therapy
    term:
      id: NCIT:C15292
      label: Palliative Therapy
  evidence:
  - reference: PMID:39457470
    reference_title: "Update on Inherited Pediatric Motor Neuron Diseases: Clinical Features and Outcome."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: OTHER
    snippet: "To date, no disease-modifying treatments have been identified for congenital SMA with associated arthrogryposis or fractures."
    explanation: >-
      Establishes the absence of disease-modifying therapy in congenital motor
      neuron disease with arthrogryposis, which is what makes supportive and
      palliative care the whole of management. Indirect because the review states
      this for congenital SMA rather than for LCCS specifically.
  - reference: PMID:39457470
    reference_title: "Update on Inherited Pediatric Motor Neuron Diseases: Clinical Features and Outcome."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: OTHER
    snippet: "These clinics focus on comprehensive supportive care, addressing various aspects of the disease, such as respiratory support, nutrition, mobility aids, and psychological assistance"
    explanation: >-
      Describes the components of multidisciplinary supportive care. Indirect
      because the review states this for ALS clinics rather than for LCCS
      specifically.
- name: Contracture Management and Rehabilitation
  therapeutic_modality: BEHAVIORAL
  description: >-
    Splinting, positioning, physiotherapy and selective orthopaedic surgery in
    survivors. Because the contractures are fixed deformations that formed before
    birth, this manages rather than reverses them, and the anaesthetic and
    respiratory risk of surgery is substantial in a child already ventilator
    dependent.
  treatment_term:
    preferred_term: Rehabilitation
    term:
      id: NCIT:C15315
      label: Rehabilitation
  evidence:
  - reference: PMID:28726266
    reference_title: "Survival among children with \"Lethal\" congenital contracture syndrome 11 caused by novel mutations in the gliomedin gene (GLDN)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Four of the affected infants survived beyond the neonatal period with intensive care, chronic ventilatory and nutritional support, and rehabilitation therapy."
    explanation: Records rehabilitation therapy as part of the survivor regimen.

discussions:
- discussion_id: lccs_lethality_label
  kind: KNOWLEDGE_GAP
  status: OPEN
  prompt: >-
    Is "lethal" still an accurate label for the LCCS group, and can the subtypes
    be stratified by the survival they actually achieve with modern support?
  attaches_to:
  - pathophysiology#Neonatal Respiratory Failure
  - has_subtypes#LCCS11
  rationale: >-
    The name encodes an outcome that the evidence no longer supports uniformly.
    Four of six GLDN-mutated children in one series survived into infancy,
    childhood and late adolescence. What is missing is any denominator: the surviving cases are reported because
    they survived, so the published series cannot say what fraction of LCCS11
    infants would survive given the same support, nor whether survival is
    driven by residual allele function, by the level of the motor-unit lesion, or
    simply by the intensity of care offered. Until that is separated out,
    counselling a family from the subtype label alone is not defensible.
  evidence:
  - reference: PMID:28726266
    reference_title: "Survival among children with \"Lethal\" congenital contracture syndrome 11 caused by novel mutations in the gliomedin gene (GLDN)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Our findings expand the genotypic and phenotypic spectrum of LCCS11 and demonstrate that the condition may not necessarily be lethal in the neonatal period."
    explanation: >-
      The primary source stating that the lethality implied by the name is not
      invariant.
- discussion_id: lccs12_gene_unassigned
  kind: KNOWLEDGE_GAP
  status: OPEN
  prompt: >-
    Does DST-b loss reach the shared fetal-akinesia node through the same
    cytoskeletal/sarcomeric route as the other muscle-side subtypes, and should
    MONDO:0981031 carry a DST gene edge?
  attaches_to:
  - has_subtypes#LCCS12
  - pathophysiology#Myofibril Assembly Failure
  rationale: >-
    Two separable questions. The first is an ontology gap rather than a
    biological one: MONDO:0981031 carries a DOID and an OMIM cross-reference but
    no `RO:0004003` gene edge, even though OMIM and MedGen assign DST, so the
    binding in this entry comes from the primary report and MONDO should be
    asked to add the edge. The second is genuinely open: dystonin is a
    cytoskeletal linker, and whether DST-b loss produces akinesia through the
    same contractile-apparatus failure as MYBPC1 and ZBTB42 or through a distinct
    cytoskeletal route has not been established. Until it is, LCCS12 is recorded
    as a subtype with its gene but is not placed on a trigger arm.
  evidence:
  - reference: PMID:40497796
    reference_title: "Deciphering DST-associated disorders: biallelic variants affecting DST-b cause a congenital myopathy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Variants that also impact DST-a besides DST-b result in a more severe, lethal congenital contracture syndrome."
    explanation: >-
      Establishes the DST assignment while leaving the route from isoform loss to
      fetal akinesia unstated, which is what this gap records.
- discussion_id: lccs10_offspine_mechanism
  kind: KNOWLEDGE_GAP
  status: OPEN
  prompt: >-
    Does LCCS10 (NEK9) reach the contractures through the shared fetal-akinesia
    node at all, or through a primary skeletal route that bypasses it?
  attaches_to:
  - has_subtypes#LCCS10
  - pathophysiology#Absent Fetal Movement
  rationale: >-
    LCCS10 is the one numbered subtype whose arm does not join the shared
    fetal-akinesia node, and that is deliberate rather than an oversight. It has
    a molecular trigger node (`Mitotic and Ciliary Regulatory Failure`), but that
    node is tagged `mechanism_confidence: HYPOTHETICAL` and its only edge is an
    `INDIRECT_UNKNOWN_INTERMEDIATES` link straight to contracture formation,
    bypassing the spine. The other eleven subtypes have a lesion somewhere in the
    motor unit - anterior horn cell, axoglial junction, sarcomere, or endocytic
    machinery - and reach the contractures by way of absent fetal movement. NEK9 is a mitotic and ciliary regulator, MONDO files
    the subtype as a skeletal dysplasia with thoracic dysplasia and short ribs,
    and the reported pulmonary hypoplasia is at least as attributable to thoracic
    constraint as to absent fetal breathing. Whether the arthrogryposis in NEK9
    disease is akinesia-driven like the rest of the series or a primary skeletal
    deformation is unresolved, and asserting a motor-unit node for it would
    manufacture a mechanism the evidence does not carry. Resolving this decides
    whether the entry's spine is genuinely shared across all twelve subtypes.
    A caution for whoever picks this up: the NEK9 case literature is dominated by
    the allelic APUG disorder (arthrogryposis, Perthes disease and upward gaze
    palsy), whose patients survive and carry compound heterozygous or missense
    alleles, whereas LCCS10 is reported in fetuses with homozygous truncating
    alleles. Visceral and cardiac findings in that literature - pyloric stenosis,
    septal defects, pulmonic stenosis - belong to APUG patients and must not be
    attributed to LCCS10. An earlier draft of this entry made exactly that error,
    and the snippets were exact and the PMID real, so nothing in the validation
    stack caught it.
  evidence:
  - reference: PMID:36712877
    reference_title: "Novel variants of NEK9 associated with neonatal arthrogryposis: Two case reports and a literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The NEK genes encode serine/threonine kinases, which play important roles in the regulation of the cell cycle and are involved in several cellular activities, such as centrosome separation, spindle assembly, chromatin condensation, nuclear envelope breakdown, spindle assembly checkpoint signaling, cytokinesis, cilia formation, and DNA damage response."
    explanation: >-
      Describes a cell-cycle and ciliary function set with no motor-unit
      component, which is why the NEK9 route to the shared node cannot be
      asserted from it.
- discussion_id: lccs_series_boundary
  kind: KNOWLEDGE_GAP
  status: OPEN
  prompt: >-
    Where does the LCCS numbered series end and the wider fetal akinesia gene
    list begin?
  attaches_to:
  - differential_diagnoses#KIF21A-related fetal akinesia
  rationale: >-
    Fetal akinesia has been associated with more than 166 loci, and genes such as
    KIF21A produce a phenotype indistinguishable from a numbered LCCS subtype
    without receiving an LCCS number. The numbering therefore reflects the order
    of historical discovery rather than a mechanistic boundary, which matters
    directly for this entry: a curator deciding whether a newly reported fetal
    akinesia gene belongs in `has_subtypes` or in `differential_diagnoses` has no
    principled criterion to apply, and the answer currently depends on whether
    OMIM happened to assign a series number.
  evidence:
  - reference: PMID:34740919
    reference_title: Bi-allelic loss-of-function variants in KIF21A cause severe fetal akinesia with arthrogryposis multiplex.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Fetal akinesia (FA) results in variable clinical presentations and has been associated with more than 166 different disease loci."
    explanation: >-
      Quantifies the locus list against which the twelve-member numbered series
      must be positioned.

notes: >-
  Concept decision (issue #9606). MONDO:0017436 is an OMIM phenotypic series
  (OMIMPS:253310) with twelve numbered members, which is the shape that usually
  argues for a `kb/groupings/` entry. It is curated here as a Disease with
  `has_subtypes` instead, because the subtypes are not a union of distinct
  diseases: each places its primary lesion at a different level of the same fetal
  motor unit, and ten of the twelve converge on one node - absent fetal movement
  - below which every finding is deformation secondary to the missing movement
  rather than a separate consequence of the gene. (LCCS10 and LCCS12 are the two
  that do not, for reasons recorded in their knowledge gaps; that they are the
  exceptions rather than the rule is what keeps the decision a disease rather
  than a grouping.) That is the
  gene-specific-trigger-substituted-per-subtype pattern the pathograph is built
  to express, so the shared spine sits at the root and the trigger arms carry
  `subtypes:` tags. A grouping would have had to duplicate that spine twelve
  times or omit it entirely.

  The pathograph runs from a molecular layer (mRNA export, PI3K-Akt signalling,
  phosphoinositide synthesis, cAMP synthesis, and NEK9's mitotic/ciliary
  functions) into cellular and tissue nodes, so the graph starts where the
  genetics actually acts rather than one level downstream of it.

  Three arms feed the convergence node. LCCS1-LCCS3 are anterior horn cell
  disease (GLE1, ERBB3, PIP5K1C - Nousiainen et al. proposed a shared mRNA
  processing pathway linking all three). LCCS2, LCCS7-LCCS9 and LCCS11 are
  axoglial: Schwann cell myelination failure in ERBB3, ADCY6 and ADGRG6 disease,
  and node-of-Ranvier assembly failure in CNTNAP1 and GLDN disease, which their
  discoverers group explicitly as inherited nodopathies. The muscle side is two
  nodes rather than one: MYBPC1 and ZBTB42 (LCCS4, LCCS6) fail myofibril
  assembly, while DNM2 (LCCS5) fails endocytic trafficking, which is also what
  gives LCCS5 the haemorrhagic findings the others lack. ERBB3 appears on two
  arms because the reported mechanism spans both anterior horn atrophy and
  Schwann cell precursor loss.

  Two subtypes are deliberately not on an arm. LCCS10 (NEK9) has a molecular
  node but only an `INDIRECT_UNKNOWN_INTERMEDIATES` edge that bypasses the
  akinesia spine, because NEK9's reported functions are mitotic and ciliary and
  MONDO files the subtype as a skeletal dysplasia. LCCS12 (DST) carries its gene
  but no node, because whether DST-b loss reaches akinesia through the
  contractile-apparatus route is unestablished. Both are recorded as knowledge
  gaps rather than resolved by assertion.

  Relationship to existing entries. `Arthrogryposis_Multiplex_Congenita` is the
  parent clinical phenotype and is deliberately curated there as an
  etiologically heterogeneous descriptive syndrome that does not assert a
  universal reduced-fetal-movement mechanism. This entry is the narrower,
  Mendelian, prenatal-lethal subset where that mechanism is established, so the
  two are complementary rather than overlapping. `CHRNA1-associated_Fetal_Hypo-akinesia_Disorder_of_Prenatal_Onset`
  is a separate fetal akinesia entity with a neuromuscular junction lesion and no
  LCCS series number.

  What is deliberately absent. No `clinical_trials` - the falcon report's
  ClinicalTrials.gov search found no interventional LCCS trial, and there is no
  approved disease-modifying pharmacotherapy, gene therapy or RNA therapy for any
  subtype. No `datasets` - no LCCS-specific omics resource was identified, and
  fabricating an accession from a causal-gene search is exactly the Named Entity
  Confusion the dataset SOP warns about. No `animal_models` section despite the
  zebrafish work on GLE1, ZBTB42 and ADCY6 being cited as evidence: those results
  are used to support mechanism nodes, and building out `modeled_mechanisms`
  links with fidelity and readout detail is a worthwhile follow-up rather than
  something to assert thinly here.

  Nomenclature. LCCS5 is filed in MONDO under `fetal akinesia-cerebral and
  retinal hemorrhage syndrome` (MONDO:0014149) rather than a numbered label, and
  LCCS10 under `NEK9-related lethal skeletal dysplasia` (MONDO:0014870); the
  `name` fields keep the LCCS numbering that the literature uses, with the MONDO
  label in `subtype_term`. LCCS9's gene is reported in the primary literature
  under its former symbol GPR126. MONDO:0981031 (LCCS12) carries no
  `RO:0004003` gene edge as of this curation even though OMIM and MedGen assign
  DST, so that binding is taken from the primary report and the discrepancy is
  recorded as an upstream gap to report.

references:
- reference: PMID:29959180
  title: Genetics of neuromuscular fetal akinesia in the genomics era.
- reference: PMID:35806855
  title: "Lethal Congenital Contracture Syndrome 11: A Case Report and Literature Review."
- reference: PMID:39457470
  title: "Update on Inherited Pediatric Motor Neuron Diseases: Clinical Features and Outcome."

clinical_trials: []
datasets: []

📚

References & Deep Research

References

PMID:29959180

Genetics of neuromuscular fetal akinesia in the genomics era.

No top-level findings curated for this source.

PMID:35806855

Lethal Congenital Contracture Syndrome 11: A Case Report and Literature Review.

No top-level findings curated for this source.

PMID:39457470

Update on Inherited Pediatric Motor Neuron Diseases: Clinical Features and Outcome.

No top-level findings curated for this source.

Deep Research

Falcon ▸

Lethal Congenital Contracture Syndrome: Research Report

Edison Scientific Literature 30 citations 2026-08-28T23:02:47.440117

Lethal Congenital Contracture Syndrome: Research Report

Executive summary

Lethal congenital contracture syndromes (LCCSs) are a genetically heterogeneous group of predominantly autosomal-recessive fetal-akinesia disorders. Reduced or absent fetal movement causes congenital contractures and secondary deformation—pulmonary hypoplasia, craniofacial abnormalities, growth restriction, polyhydramnios, and sometimes hydrops. “Arthrogryposis” is a descriptive finding rather than a single diagnosis; LCCS overlaps clinically with arthrogryposis multiplex congenita (AMC), fetal akinesia deformation sequence (FADS), and Pena–Shokeir syndrome type I. AMC overall occurs in approximately 1/3,000–1/5,000 births, but each molecular LCCS subtype is much rarer, usually represented by only a few families. (potrony2022lethalcongenitalcontracture pages 1-2, wambach2017survivalamongchildren pages 1-3)

The best-established molecular forms in the retrieved evidence involve GLE1, ERBB3, PIP5K1C, ZBTB42, CNTNAP1, ADCY6, NEK9, and GLDN. These converge on failure of the fetal motor unit or musculoskeletal development through RNA metabolism, motor-neuron survival, axon–glial organization, nodal conduction, phosphoinositide/cAMP signaling, mitosis, and ciliogenesis. The label “lethal” is not absolute: especially in GLDN-related LCCS11, survival into childhood or adolescence is possible with intensive respiratory and nutritional support. (beecroft2018geneticsofneuromuscular pages 3-4, wambach2017survivalamongchildren pages 1-3)

Subtype	OMIM disease ID	Gene	Molecular role / mechanism	Hallmark distinguishing findings	Lethality / survival	Key evidence / date
LCCS1	253310	GLE1	Regulates mRNA export and translation; GLE1-related fetal motor neuron disease with anterior horn involvement (trabacca2024updateoninherited pages 11-12, nousiainen2011molecularbackgroundofa pages 24-26)	Complete fetal immobility, severe hydrops, intrauterine growth restriction; flexion contractures, knee hyperextension, pulmonary hypoplasia, micrognathia; fetal death often before 32 weeks (nousiainen2011molecularbackgroundofa pages 24-26, trabacca2024updateoninherited pages 11-12)	Usually prenatal lethal / fetal death before 32 weeks (trabacca2024updateoninherited pages 11-12, nousiainen2011molecularbackgroundofa pages 24-26)	Nousiainen thesis evidence summarized in retrieved text; Trabacca review 2024 (nousiainen2011molecularbackgroundofa pages 24-26, trabacca2024updateoninherited pages 11-12)
LCCS2	not established from retrieved evidence	ERBB3	Gene assignment supported in review-level retrieved evidence; detailed molecular mechanism not established from primary retrieved text (trabacca2024updateoninherited pages 11-12)	Cranial and ocular abnormalities, enlarged bladder with hydronephrosis, cystic kidney changes (trabacca2024updateoninherited pages 11-12)	Usually fatal shortly after birth (trabacca2024updateoninherited pages 11-12)	Trabacca review 2024; pediatric motor neuron review evidence in conversation (trabacca2024updateoninherited pages 11-12)
LCCS3	611369	PIP5K1C	Phosphatidylinositol-4-phosphate 5-kinase; synthesizes PIP2; reported disease mechanism is haploinsufficiency / truncating loss of function in retrieved evidence (zhang2024novelpip5k1cvariant pages 1-2, zhang2024novelpip5k1cvariant pages 2-5)	Small gestational age, severe multiple joint contractures, muscle atrophy, respiratory failure; detailed fetal findings include talipes equinovarus, extended knees, closed hands/overlapping fingers; possible bilateral dilated lateral ventricles in one fetus (zhang2024novelpip5k1cvariant pages 1-2, zhang2024novelpip5k1cvariant pages 2-5)	Early death due to respiratory failure; prior five reported individuals all died in summarized table, plus two Chinese fetuses described (zhang2024novelpip5k1cvariant pages 1-2, zhang2024novelpip5k1cvariant pages 2-5)	Zhang et al., BMC Pediatrics, 2024; novel c.949_952dup p.S318Ifs28 plus c.688_689del p.G230Qfs114 (zhang2024novelpip5k1cvariant pages 1-2, zhang2024novelpip5k1cvariant pages 2-5)
LCCS6	613915	ZBTB42	Not established from retrieved evidence beyond subtype-gene association mention in review evidence (beecroft2018geneticsofneuromuscular pages 3-3)	Not established from retrieved evidence	Not established from retrieved evidence	Mentioned in Beecroft review 2018 as LCCS6/ZBTB42 association (beecroft2018geneticsofneuromuscular pages 3-3)
LCCS7	inconsistent in retrieved evidence: 616286 vs 607598	CNTNAP1	CASPR; essential node of Ranvier component for saltatory conduction; severe axoglial / myelinated axon abnormalities with very low motor nerve conduction velocity (laquerriere2014mutationsincntnap1 pages 1-2, beecroft2018geneticsofneuromuscular pages 3-4)	Severe arthrogryposis / fetal akinesia with peripheral nerve axoglial defects; marked reduction in motor nerve conduction velocity (<10 m/s) (laquerriere2014mutationsincntnap1 pages 1-2)	In review summary, 5 of 7 patients died within 2 months; exact survival spectrum not fully established here (beecroft2018geneticsofneuromuscular pages 3-4)	Laquerriere et al., Hum Mol Genet, 2014; Beecroft review 2018 notes OMIM inconsistency in retrieved evidence (laquerriere2014mutationsincntnap1 pages 1-2, beecroft2018geneticsofneuromuscular pages 3-4)
LCCS8	616287	ADCY6	Adenylyl cyclase type 6; membrane-associated enzyme catalyzing cAMP formation; associated with lack of PNS myelin / hypomyelinating neuropathy in reported cases (agolini2020expandingtheclinical pages 1-6, laquerriere2014mutationsincntnap1 pages 1-2)	Distal joint contractures, severe hypotonia, lack of swallowing, absent autonomous respiratory function and deep tendon reflexes; may include hydrocephalus, severe muscle loss, hypomyelinating neuropathy (agolini2020expandingtheclinical pages 1-6)	Original reported siblings died within first 3 months; additional patient died at 36 months after intensive support (agolini2020expandingtheclinical pages 1-6, beecroft2018geneticsofneuromuscular pages 3-4)	Agolini et al., Clin Genet, 2020; Laquerriere et al., 2014 discovery paper (agolini2020expandingtheclinical pages 1-6, laquerriere2014mutationsincntnap1 pages 1-2)
LCCS10	617022	NEK9	NIMA-related serine/threonine kinase; mitotic spindle / centrosome functions; linked to defective primary cilia formation, with broader cilia/autophagy evidence from NEK9 biology (liu2023novelvariantsof pages 1-2, yamamoto2021nek9regulatesprimary pages 1-2)	Multiple joint contractures / arthrogryposis; severe cases reported with shortened limbs in literature summaries; neonatal cases included camptodactyly, stiff neck, pyloric stenosis, heart defects (liu2023novelvariantsof pages 1-2, liu2023novelvariantsof pages 2-5)	Historically described as lethal fetal form, but 2023 report expands to neonatal survivors/discharges; full survival range not established from retrieved evidence (liu2023novelvariantsof pages 1-2, liu2023novelvariantsof pages 2-5)	Liu et al., Front Genet, 2023; novel variants c.717C>A, c.2824delA, c.61G>T not in ClinVar/HGMD/gnomAD (liu2023novelvariantsof pages 1-2, liu2023novelvariantsof pages 2-5)
LCCS11	617194	GLDN	Gliomedin; required for nodes of Ranvier formation and peripheral nervous system development; GLDN variants disrupt nodal interactions and can be framed as FADS-spectrum nodopathy (potrony2022lethalcongenitalcontracture pages 1-2, mis2020thelatestfads pages 1-2)	Hydrops, short long bones, fixed limb joints, absent fetal movements, polyhydramnios, growth restriction, pulmonary hypoplasia, retrognathia; distal arthrogryposis (potrony2022lethalcongenitalcontracture pages 1-2)	Not invariably lethal: 4/6 additional patients in 2017 survived beyond neonatal period with intensive chronic respiratory/nutritional support; condition may extend into childhood/adolescence (wambach2017survivalamongchildren pages 1-3, mis2020thelatestfads pages 1-2)	Wambach et al., Hum Mutat, 2017; Potrony et al., J Clin Med, 2022; Mis et al., AJMG A, 2020 (wambach2017survivalamongchildren pages 1-3, potrony2022lethalcongenitalcontracture pages 1-2, mis2020thelatestfads pages 1-2)

Table: This table summarizes lethal congenital contracture syndrome subtypes supported by evidence retrieved in the conversation. It highlights subtype-gene relationships, distinguishing findings, survival patterns, and places where the evidence base is incomplete or internally inconsistent.

1. Disease information

Definition and scope

LCCS is characterized by prenatal-onset hypokinesia or akinesia, multiple fixed joint contractures, and severe neuromuscular or skeletal developmental disease. Contractures are generally non-progressive structural consequences of impaired fetal movement, although respiratory, nutritional, and neurologic morbidity may evolve after birth in survivors. Secondary deformation can include pulmonary hypoplasia, micrognathia/retrognathia, short neck, pterygia, shortened umbilical cord, polyhydramnios, impaired gut motility, and growth restriction. (nousiainen2011molecularbackgroundofa pages 24-26, potrony2022lethalcongenitalcontracture pages 1-2)

Synonyms/overlap terms: multiple congenital contractures; arthrogryposis multiplex congenita; fetal akinesia deformation sequence; Pena–Shokeir syndrome type I; for LCCS1, multiple contracture syndrome, Finnish type or Herva disease. GLE1-related lethal arthrogryposis with anterior horn-cell disease (LAAHD/CAAHD) is allelic and clinically overlapping but often distinguished from classic LCCS1. (nousiainen2011molecularbackgroundofa pages 24-26, potrony2022lethalcongenitalcontracture pages 1-2, trabacca2024updateoninherited pages 11-12)

Identifiers

The umbrella disorder does not have one reliably verified identifier in the retrieved literature; subtype-specific OMIM records are preferable. Verified examples are LCCS1, OMIM 253310; LCCS3, 611369; LCCS6, 613915; LCCS8, 616287; LCCS10, 617022; and LCCS11, 617194. Retrieved sources conflicted for LCCS7 (616286 versus 607598), so an operational knowledge base should resolve this directly against the current OMIM release before ingestion. No umbrella MONDO ID, dedicated ICD-10/ICD-11 code, or MeSH heading was verified here; clinically, cases are usually coded under arthrogryposis/multiple congenital malformations plus molecular diagnosis. (beecroft2018geneticsofneuromuscular pages 3-3, beecroft2018geneticsofneuromuscular pages 3-4, liu2023novelvariantsof pages 1-2, zhang2024novelpip5k1cvariant pages 1-2)

The evidence is aggregated disease-level literature, principally family reports, fetal/neonatal case series, molecular studies, and reviews—not patient-level EHR data.

2. Etiology and risk/protective factors

The primary cause is biallelic germline pathogenic variation. Most reported variants are homozygous in consanguineous/founder populations or compound heterozygous in unrelated parents. Disease mechanisms are commonly loss of function, including nonsense, frameshift, splice-disrupting, or damaging missense alleles. (liu2023novelvariantsof pages 1-2, zhang2024novelpip5k1cvariant pages 1-2, agolini2020expandingtheclinical pages 1-6)

The principal risk factors are parental carrier status, consanguinity, ancestry-specific founder alleles, and an affected pregnancy or sibling. The classic GLE1 LCCS1 allele is enriched in the Finnish disease heritage; the early PIP5K1C LCCS3 series involved an Israeli Bedouin kindred. A 2024 population analysis used 125,748 exomes and 15,708 genomes from gnomAD to estimate recessive neuromuscular carrier burdens, but it did not provide a sufficiently supported LCCS-specific prevalence estimate in the retrieved text. (beecroft2018geneticsofneuromuscular pages 3-4, choi2024globalcarrierfrequency pages 6-8, zhang2024novelpip5k1cvariant pages 2-5)

No reproducible environmental, lifestyle, infectious, sex-specific, or age-related risk factor is established for molecular LCCS. Likewise, no protective allele, modifier gene, protective exposure, or validated gene–environment interaction has been demonstrated. Maternal infection, oligohydramnios, uterine constraint, autoimmune disease, and teratogens are important alternative causes of fetal akinesia/arthrogryposis, not established causes of genetically confirmed LCCS. (illes2024heterogenicgeneticbackground pages 1-2)

3. Phenotypes

Core ontology-ready phenotypes include:

Decreased/absent fetal movement—prenatal, severe, causally upstream; HP:0001558 Decreased fetal movement or HP:0001989 Fetal akinesia.
Multiple congenital joint contractures/arthrogryposis—congenital, usually severe and structurally stable; HP:0002804 Arthrogryposis multiplex congenita and HP:0012453 Arthrogryposis.
Talipes equinovarus—often bilateral; HP:0001762.
Camptodactyly/overlapping fingers/closed hands—HP:0012385, HP:0010557.
Knee hyperextension or fixed flexion, elbow/wrist/hip contractures—joint-specific contracture terms.
Muscle hypoplasia/atrophy and hypotonia—HP:0003202, HP:0001252; neurogenic denervation may be present.
Areflexia—HP:0001284.
Pulmonary hypoplasia and respiratory failure—HP:0002089, HP:0002878; major determinants of mortality.
Polyhydramnios—HP:0001561, often reflecting impaired swallowing.
Hydrops fetalis—HP:0001789, particularly prominent in LCCS1 and some LCCS11 fetuses.
Intrauterine growth restriction—HP:0001511.
Micrognathia/retrognathia and short neck—HP:0000347/HP:0000278, HP:0000470.
Pterygia—HP:0001059.
Feeding/swallowing difficulty—HP:0011968/HP:0002015.

Subtype-enriched findings include renal/urinary abnormalities and cranio-ocular anomalies in ERBB3-related LCCS2; hypomyelinating neuropathy and vocal-cord paralysis in ADCY6-related LCCS8; pyloric stenosis and cardiac defects in some NEK9 patients; and possible ventriculomegaly in PIP5K1C LCCS3. In the 2024 PIP5K1C report, all seven detailed patients had dyskinesia and contractures; all five original Bedouin patients and one Chinese fetus died from respiratory insufficiency. Ventriculomegaly occurred in only one of two genetically identical Chinese fetuses and therefore remains a provisional association. (trabacca2024updateoninherited pages 11-12, liu2023novelvariantsof pages 2-5, zhang2024novelpip5k1cvariant pages 2-5, agolini2020expandingtheclinical pages 1-6)

Formal EQ-5D, SF-36, PROMIS, or disease-specific quality-of-life data are unavailable. Functional burden in survivors is nevertheless profound: ventilation, tracheostomy, gastrostomy, mobility impairment, rehabilitation, and recurrent hospitalization may be required. Some GLDN survivors have preserved cognition and developmental progress despite severe neonatal disease. (mis2020thelatestfads pages 1-2, wambach2017survivalamongchildren pages 1-3)

4. Genetic and molecular information

All established LCCS alleles are constitutional/germline, not somatic. Representative variants include:

PIP5K1C/LCCS3: homozygous c.757G>A (p.Asp253Asn) in five Bedouin patients; compound-heterozygous c.688_689del (p.G230Qfs114) and novel c.949_952dup (p.S318Ifs28) in two Chinese fetuses. The latter pair was classified pathogenic under ACMG/AMP criteria PVS1+PM2+PP1+PP4; both predict truncation, and p.S318Ifs*28 was considered unlikely to escape nonsense-mediated decay. All known variants summarized in that study localized to the PIPK domain. (zhang2024novelpip5k1cvariant pages 1-2, zhang2024novelpip5k1cvariant pages 2-5)
NEK9/LCCS10 spectrum: c.717C>A, c.2824delA, and c.61G>T were reported in two neonates as compound-heterozygous truncating variants; none was present in ClinVar, HGMD, or gnomAD at publication. The report emphasizes mutation-dependent phenotypic breadth from lethal fetal disease to neonatal arthrogryposis. (liu2023novelvariantsof pages 1-2, liu2023novelvariantsof pages 2-5)
ADCY6/LCCS8: compound-heterozygous c.1535+1G>A and c.3007G>A (p.Glu1003Lys) were identified in a severely affected girl; p.Glu1003Lys was absent from gnomAD. Earlier families carried homozygous missense alleles. (agolini2020expandingtheclinical pages 1-6)
CNTNAP1/LCCS7: four unrelated families had homozygous frameshift variants causing severe axoglial disease. (laquerriere2014mutationsincntnap1 pages 1-2)
GLDN/LCCS11: both homozygous and compound-heterozygous variants are established; p.Leu365Phe and p.Arg393Lys have functional evidence in a surviving patient. (mis2020thelatestfads pages 1-2, wambach2017survivalamongchildren pages 1-3)

No validated modifier genes, disease-specific methylation signature, recurrent pathogenic chromosomal rearrangement, or epigenetic mechanism is established. Normal karyotype/CMA in affected fetuses is common and does not exclude LCCS. (potrony2022lethalcongenitalcontracture pages 1-2, zhang2024novelpip5k1cvariant pages 1-2)

5. Environmental information

No toxin, radiation exposure, pollutant, occupation, diet, smoking, alcohol, exercise pattern, or infectious agent has been shown to cause or modify genetically confirmed LCCS. These variables matter chiefly in the differential diagnosis of fetal akinesia. LCCS is neither infectious nor transmissible.

6. Mechanism and pathophysiology

Unifying causal chain

Biallelic gene dysfunction → impaired motor-neuron development/survival, axonal conduction, neuromuscular signaling, or skeletal/ciliary development → reduced fetal muscle contraction → fetal akinesia → persistent joint positioning and connective-tissue fixation → multiple contractures; impaired breathing/swallowing movements → pulmonary hypoplasia, polyhydramnios, respiratory and feeding failure. (illes2024heterogenicgeneticbackground pages 1-2, potrony2022lethalcongenitalcontracture pages 1-2)

Gene-specific mechanisms

GLE1: defective regulation of nuclear mRNA export and translation initiation/termination is associated with anterior-horn motor-neuron loss and severe skeletal-muscle atrophy. Suggested GO terms: mRNA export from nucleus (GO:0006406), translation initiation (GO:0006413), translation termination (GO:0006415), motor neuron development (GO:0021675). (trabacca2024updateoninherited pages 11-12)
CNTNAP1/CASPR: disruption of axon–glial paranodal architecture impairs saltatory conduction. Patients had motor nerve conduction velocities below 10 m/s and severe abnormalities of nodes of Ranvier and myelinated axons. Suggested GO: node of Ranvier assembly and myelination; CL: motor neuron, Schwann cell. (laquerriere2014mutationsincntnap1 pages 1-2)
GLDN/gliomedin: gliomedin interacts with NF186 and NrCAM to cluster sodium channels at peripheral nodes of Ranvier. Loss produces a developmental nodopathy, fetal hypomotility, and respiratory dysfunction. Suggested GO: node of Ranvier assembly, sodium-channel clustering; GO-CC: node of Ranvier; CL: Schwann cell and peripheral sensory/motor neuron. (mis2020thelatestfads pages 1-2, wambach2017survivalamongchildren pages 1-3)
ADCY6: adenylyl cyclase 6 generates cAMP downstream of GPCR signaling. Biallelic dysfunction is associated with absent or deficient peripheral myelin, severe neurogenic damage, hypotonia, and areflexia. Suggested GO: cAMP biosynthetic process (GO:0006171), G protein-coupled receptor signaling pathway; CHEBI: cyclic AMP (CHEBI:17489). (laquerriere2014mutationsincntnap1 pages 1-2, agolini2020expandingtheclinical pages 1-6)
PIP5K1C: the lipid kinase converts PI4P to phosphatidylinositol-4,5-bisphosphate (PIP2), supporting calcium signaling, actin dynamics, endocytosis/exocytosis, and synaptic function. Pip5k1c-null mice show approximately 50% lower brain PIP2 and impaired depolarization-dependent PIP2 synthesis at nerve terminals. Suggested GO: phosphatidylinositol phosphorylation, synaptic vesicle exocytosis, actin cytoskeleton organization; CHEBI: PI4P and PI(4,5)P2. (zhang2024novelpip5k1cvariant pages 1-2, zhang2024novelpip5k1cvariant pages 2-5)
NEK9: this serine/threonine kinase participates in spindle assembly, centrosome separation, mitosis, and primary-cilium formation. Cell/mouse experiments show NEK9 acts as a selective-autophagy adaptor for MYH9; loss causes MYH9 accumulation, actin stabilization, and impaired ciliogenesis, while MYH9 depletion rescues ciliogenesis in mutant cells. Suggested GO: mitotic spindle organization, centrosome separation, cilium assembly (GO:0060271), selective autophagy; GO-CC: centrosome, primary cilium, autophagosome. (yamamoto2021nek9regulatesprimary pages 1-2, liu2023novelvariantsof pages 1-2)

Immune dysregulation, chronic inflammation, and a disease-specific metabolomic/lipidomic signature are not established. Beyond gene-focused experiments, no mature LCCS single-cell, spatial-transcriptomic, clinical proteomic, or integrated multi-omic atlas was identified.

7. Anatomical structures affected

Primary involvement is in the fetal neuromuscular system: spinal anterior-horn motor neurons, peripheral nerves and myelin, nodes/paranodes of Ranvier, neuromuscular unit, and skeletal muscle. Secondary deformation affects limb joints, hands, feet, jaw, neck, thorax, and lungs. Kidneys/urinary tract are particularly relevant in LCCS2; brain anomalies occur variably rather than universally. (nousiainen2011molecularbackgroundofa pages 24-26, trabacca2024updateoninherited pages 11-12, laquerriere2014mutationsincntnap1 pages 1-2)

Suggested UBERON annotations include spinal cord (UBERON:0002240), peripheral nervous system (UBERON:0000010), skeletal muscle tissue (UBERON:0001134), lung (UBERON:0002048), limb joint, hand, foot, mandible, kidney, and urinary bladder. Laterality is generally bilateral/symmetric, especially talipes and limb contractures, but asymmetry can occur.

8. Temporal development

Onset is prenatal, often detectable in the late first or second trimester through reduced movement and abnormal limb positioning. Classic LCCS1 can be recognized ultrasonographically around 11–12 weeks and commonly ends in fetal death before 32 weeks. Other forms may present at birth with respiratory failure, hypotonia, areflexia, feeding failure, or fixed contractures. (nousiainen2011molecularbackgroundofa pages 24-26, trabacca2024updateoninherited pages 11-12)

There are no validated disease stages or remission patterns. The mechanistic injury occurs during a critical fetal-development window; established contractures do not spontaneously reverse. In survivors, respiratory dependence may improve—one GLDN patient was weaned from respiratory support by 14 months—but feeding, mobility, and orthopedic needs may persist. (mis2020thelatestfads pages 1-2)

9. Inheritance and population

Inheritance is usually autosomal recessive. For two carrier parents, the Mendelian recurrence risk is 25% affected, 50% carrier, and 25% unaffected/non-carrier in each pregnancy. Penetrance appears high for clearly pathogenic biallelic alleles, but expressivity and lethality vary by gene and allele. Anticipation is not expected. Germline mosaicism has not been quantified; it remains a residual consideration when apparently de novo findings are encountered.

Consanguinity has played a major role in gene discovery. GLE1 LCCS1 is strongly associated with Finland and a founder allele; PIP5K1C LCCS3 was initially described in Bedouin patients. Outside founder groups, compound heterozygosity is common. No reliable sex bias exists because autosomal-recessive disease should affect both sexes equally. Subtype-specific incidence and carrier frequency remain unknown. (beecroft2018geneticsofneuromuscular pages 3-4, zhang2024novelpip5k1cvariant pages 1-2, zhang2024novelpip5k1cvariant pages 2-5)

10. Diagnostics

Prenatal and clinical evaluation

Serial expert ultrasound should assess fetal movement, limb position, hands/feet, jaw, growth, amniotic fluid, hydrops, lung/thoracic development, kidneys/bladder, and CNS. Fetal MRI may clarify brain, spinal, pulmonary, or muscular abnormalities. Postmortem fetal examination remains valuable after pregnancy loss; classic LCCS1 may show profound anterior-horn and skeletal-muscle atrophy despite a macroscopically normal brain. (nousiainen2011molecularbackgroundofa pages 24-26, potrony2022lethalcongenitalcontracture pages 1-2)

In liveborn infants, useful tests include blood chemistry and creatine kinase, echocardiography, renal imaging, brain/spinal MRI, EMG and nerve-conduction studies, swallow/respiratory evaluation, and selected muscle/nerve biopsy. These tests characterize the affected compartment but are not individually diagnostic. ADCY6 disease may show chronic neurogenic EMG/biopsy abnormalities; CNTNAP1 disease can produce motor conduction below 10 m/s. (laquerriere2014mutationsincntnap1 pages 1-2, agolini2020expandingtheclinical pages 1-6)

Genetic-testing algorithm

Confirm fetal akinesia/AMC phenotype and construct a three-generation pedigree.
Perform karyotype or chromosomal microarray when structural anomalies are present.
Use rapid trio WES or WGS, preferably with CNV and splice-aware analysis. A comprehensive fetal-akinesia/arthrogryposis panel should include the established LCCS genes plus broader motor-neuron, peripheral-nerve, neuromuscular-junction, myopathy, skeletal-dysplasia, and congenital-glycosylation genes.
Confirm candidate variants and phase by Sanger sequencing or orthogonal methods; apply ACMG/AMP classification and phenotype segregation.
Reanalyze negative exomes and consider genome/RNA sequencing where a splice, structural, deep-intronic, or poorly covered variant is suspected.

WES has achieved diagnostic rates up to approximately 60% in arthrogryposis cohorts, although this is not an LCCS-specific sensitivity. In recurrent fetal structural anomalies, a separate meta-analysis reported a 40% incremental exome yield, illustrating the utility of trio sequencing in comparable prenatal settings. (potrony2022lethalcongenitalcontracture pages 1-2)

Differential diagnosis

Major alternatives include SMN1-related SMA, congenital myopathies and muscular dystrophies, congenital myasthenic syndromes, CNTN1/NFASC nodopathies, multiple-pterygium syndromes, cerebro-oculo-facio-skeletal disorders, skeletal dysplasias, chromosomal disease, mitochondrial disorders, congenital infection, maternal myasthenia/antibody-mediated fetal akinesia, oligohydramnios, uterine constraint, and teratogen exposure. Recent sequencing continues to expand the differential: biallelic KIF21A loss of function was identified in severe fetal akinesia with arthrogryposis and pulmonary hypoplasia in a 2023 study. (falb2023bialleliclossoffunctionvariants pages 9-9, illes2024heterogenicgeneticbackground pages 1-2)

11. Outcome and prognosis

Mortality is driven principally by pulmonary hypoplasia, respiratory muscle/diaphragm dysfunction, aspiration, and infection. Classic LCCS1 is usually prenatally lethal; LCCS2 is generally fatal shortly after birth; reported PIP5K1C LCCS3 patients died from respiratory insufficiency. ADCY6 cases died from infancy to 36 months in the available series. (trabacca2024updateoninherited pages 11-12, zhang2024novelpip5k1cvariant pages 2-5, agolini2020expandingtheclinical pages 1-6)

GLDN disease demonstrates why genotype-specific counseling is essential. Wambach et al. reported six patients from four families, of whom four survived beyond the neonatal period into infancy, childhood, or late adolescence with intensive care and chronic respiratory/nutritional support. Thus, there are no defensible universal 5- or 10-year survival estimates, and “lethal” should not be interpreted as invariant neonatal death. (wambach2017survivalamongchildren pages 1-3)

No validated prognostic biomarker exists. Likely clinical predictors include severity of fetal akinesia, pulmonary hypoplasia, autonomous respiratory capacity, swallowing ability, extent of denervation/hypomyelination, and the residual function of the causal allele.

12. Treatment and current applications

There is no approved disease-modifying pharmacotherapy, gene therapy, cell therapy, RNA therapy, or genotype-directed drug for LCCS, and the ClinicalTrials.gov search identified no relevant LCCS interventional trial. A 2024 pediatric motor-neuron review likewise reported no disease-modifying treatment for congenital SMA/arthrogryposis conditions. (trabacca2024updateoninherited pages 11-12)

Management is supportive and individualized:

neonatal resuscitation and invasive/noninvasive ventilation;
tracheostomy, airway-clearance/cough-assist, sleep and gas-exchange monitoring;
swallow assessment, aspiration prevention, nasogastric or gastrostomy feeding;
physical and occupational therapy, splinting, positioning, and contracture management;
orthopedic surgery only when expected benefits exceed anesthetic and respiratory risks;
treatment of hydrocephalus, cardiac, renal, gastrointestinal, and infectious complications;
palliative-care involvement for uniformly severe prenatal/neonatal presentations.

Suggested NCIt intervention concepts include Mechanical Ventilation, Tracheostomy, Gastrostomy, Physical Therapy, Occupational Therapy, Orthopedic Surgery, Genetic Counseling, and Palliative Care. GLDN and ADCY6 survivor reports provide real-world evidence for chronic ventilation, gastrostomy, rehabilitation, and multidisciplinary follow-up rather than molecular therapy. (mis2020thelatestfads pages 1-2, wambach2017survivalamongchildren pages 1-3, agolini2020expandingtheclinical pages 1-6)

13. Prevention

There is no vaccine, lifestyle intervention, environmental remediation, or prophylactic drug that prevents a pathogenic biallelic genotype. Prevention is reproductive:

cascade carrier testing after a molecular diagnosis;
ancestry- or family-history-informed preconception carrier screening;
partner testing;
preimplantation genetic testing for monogenic disease;
targeted chorionic-villus or amniotic-fluid testing;
early expert ultrasound and, where appropriate, rapid prenatal trio sequencing.

For a known familial genotype, targeted molecular testing is more definitive than ultrasound, because fetal movement abnormalities may emerge after the optimal window for reproductive decision-making. Genetic counseling should address the 25% recurrence risk, variable survival in some subtypes, reproductive options, and residual risks including assay limitations.

14. Other species and natural disease

No well-established naturally occurring veterinary counterpart or zoonotic transmission was identified. The relevant proteins and developmental processes are evolutionarily conserved, but most comparative evidence comes from induced laboratory models rather than natural disease. Suggested taxa include Mus musculus (NCBI Taxon 10090) and Danio rerio (7955).

15. Model organisms and experimental systems

CNTNAP1/ADCY6 zebrafish knockdown: morpholino experiments were used in the original human genetics study to support developmental neuromuscular effects. Limitations include transient knockdown and imperfect equivalence to human biallelic alleles. (laquerriere2014mutationsincntnap1 pages 1-2)
Pip5k1c-null mouse: reduced brain PIP2 by approximately 50% and impaired nerve-terminal PIP2 synthesis/synaptic function, supporting phosphoinositide and presynaptic mechanisms. The model is useful mechanistically but does not by itself establish every human fetal phenotype. (zhang2024novelpip5k1cvariant pages 2-5)
Nek9 models: homozygous knockout is embryonic lethal. LIR-mutant mice show impaired kidney ciliogenesis; cultured mutant cells accumulate MYH9, and MYH9 depletion rescues ciliogenesis. These models distinguish NEK9’s autophagy/ciliary role but do not fully reproduce human contracture syndrome. (yamamoto2021nek9regulatesprimary pages 1-2)
Patient fibroblasts: NEK9 LCCS10 fibroblasts have shown defective primary-cilium formation. (yamamoto2021nek9regulatesprimary pages 1-2)
GLDN variant assays: functional testing of p.Leu365Phe, p.Arg393Lys, and other patient variants strengthens pathogenic classification and nodal-mechanism inference. (mis2020thelatestfads pages 1-2)

No validated LCCS organoid, iPSC-derived neuromuscular-junction platform, or therapeutic CRISPR screen was identified in the 2023–2024 evidence set.

Recent developments and expert assessment, 2023–2024

PIP5K1C/LCCS3 expansion (published March 2024): two affected Chinese fetuses increased the detailed published count from five to seven. The study added pathogenic c.949_952dup (p.S318Ifs*28), documented compound heterozygosity with c.688_689del, and proposed ventriculomegaly as a possible but unconfirmed phenotype. DOI: https://doi.org/10.1186/s12887-024-04674-6. The authors’ abstract states: “These findings expanded the genetic variant spectrum of PIP5K1C and enriched the clinical features of LCCS3.” (zhang2024novelpip5k1cvariant pages 1-2, zhang2024novelpip5k1cvariant pages 2-5)
NEK9 phenotype expansion (published 4 January 2023): two premature neonates carried three novel truncating alleles, broadening NEK9 disease beyond a uniformly lethal fetal skeletal phenotype. DOI: https://doi.org/10.3389/fgene.2022.989215. The abstract concludes that “different types of mutations in NEK9 lead to different phenotypes.” (liu2023novelvariantsof pages 1-2, liu2023novelvariantsof pages 2-5)
Broader fetal-akinesia gene discovery (2023): biallelic KIF21A loss of function was reported in five fetuses from two families with severe neurogenic fetal akinesia, arthrogryposis, pulmonary hypoplasia, and facial dysmorphism. DOI: https://doi.org/10.1136/jmedgenet-2021-108064. This reinforces expert recommendations for broad trio-exome/genome analysis rather than narrow sequential single-gene testing. (falb2023bialleliclossoffunctionvariants pages 9-9)
Current expert interpretation (October 2024): inherited pediatric motor-neuron disease remains genetically heterogeneous, with LCCS1 viewed as a severe GLE1-related RNA-metabolism/anterior-horn disease and LCCS2 as ERBB3-related multisystem fetal akinesia. Evidence remains dominated by case reports, and no disease-modifying therapy is available. DOI: https://doi.org/10.3390/genes15101346. (trabacca2024updateoninherited pages 11-12)

Evidence limitations

The LCCS literature consists mainly of very small, ancestry-enriched families, fetal pathology series, and survivor case reports. Consequently, phenotype percentages, penetrance, allele frequencies, incidence, survival curves, quality-of-life scores, treatment-response rates, and genotype–phenotype correlations are generally unavailable or unstable. Several older subtype assignments and identifiers vary across secondary sources. Database ingestion should therefore retain gene and OMIM subtype provenance, publication date, evidence type (human/model/in vitro), and uncertainty rather than treating “LCCS” as one homogeneous disorder.

References

(potrony2022lethalcongenitalcontracture pages 1-2): Miriam Potrony, Antoni Borrell, Narcís Masoller, Alfons Nadal, Leonardo Rodriguez-Carunchio, Karmele Saez de Gordoa Elizalde, Juan Francisco Quesada-Espinosa, Jose Luis Villanueva-Cañas, Montse Pauta, Meritxell Jodar, Irene Madrigal, Celia Badenas, Maria Isabel Alvarez-Mora, and Laia Rodriguez-Revenga. Lethal congenital contracture syndrome 11: a case report and literature review. Journal of Clinical Medicine, 11:3570, Jun 2022. URL: https://doi.org/10.3390/jcm11133570, doi:10.3390/jcm11133570. This article has 7 citations.
(wambach2017survivalamongchildren pages 1-3): Jennifer A. Wambach, Georg M. Stettner, Tobias B. Haack, Karin Writzl, Andreja Škofljanec, Aleš Maver, Francina Munell, Stephan Ossowski, Mattia Bosio, Daniel J. Wegner, Marwan Shinawi, Dustin Baldridge, Bader Alhaddad, Tim M. Strom, Dorothy K. Grange, Ekkehard Wilichowski, Robin Troxell, James Collins, Barbara B. Warner, Robert E. Schmidt, Alan Pestronk, F. Sessions Cole, and Robert Steinfeld. Survival among children with “lethal” congenital contracture syndrome 11 caused by novel mutations in the gliomedin gene (gldn). Human Mutation, 38:1477-1484, Nov 2017. URL: https://doi.org/10.1002/humu.23297, doi:10.1002/humu.23297. This article has 24 citations and is from a domain leading peer-reviewed journal.
(beecroft2018geneticsofneuromuscular pages 3-4): Sarah Jane Beecroft, Marcus Lombard, David Mowat, Catriona McLean, Anita Cairns, Mark Davis, Nigel G Laing, and Gianina Ravenscroft. Genetics of neuromuscular fetal akinesia in the genomics era. Journal of Medical Genetics, 55:505-514, Jun 2018. URL: https://doi.org/10.1136/jmedgenet-2018-105266, doi:10.1136/jmedgenet-2018-105266. This article has 50 citations and is from a domain leading peer-reviewed journal.
(trabacca2024updateoninherited pages 11-12): Antonio Trabacca, Camilla Ferrante, Maria Carmela Oliva, Isabella Fanizza, Ivana Gallo, and Marta De Rinaldis. Update on inherited pediatric motor neuron diseases: clinical features and outcome. Oct 2024. URL: https://doi.org/10.3390/genes15101346, doi:10.3390/genes15101346. This article has 12 citations.
(nousiainen2011molecularbackgroundofa pages 24-26): H Nousiainen. Molecular background of three lethal fetal syndromes. Unknown journal, 2011.
(zhang2024novelpip5k1cvariant pages 1-2): Fang Zhang, Hongmei Guo, Xinlong Zhou, Zhengxi Deng, Qiuhong Xu, Qingming Wang, Haiming Yuan, and Jianhua Luo. Novel pip5k1c variant identified in a chinese pedigree with lethal congenital contractural syndrome 3. BMC Pediatrics, Mar 2024. URL: https://doi.org/10.1186/s12887-024-04674-6, doi:10.1186/s12887-024-04674-6. This article has 3 citations and is from a peer-reviewed journal.
(zhang2024novelpip5k1cvariant pages 2-5): Fang Zhang, Hongmei Guo, Xinlong Zhou, Zhengxi Deng, Qiuhong Xu, Qingming Wang, Haiming Yuan, and Jianhua Luo. Novel pip5k1c variant identified in a chinese pedigree with lethal congenital contractural syndrome 3. BMC Pediatrics, Mar 2024. URL: https://doi.org/10.1186/s12887-024-04674-6, doi:10.1186/s12887-024-04674-6. This article has 3 citations and is from a peer-reviewed journal.
(beecroft2018geneticsofneuromuscular pages 3-3): Sarah Jane Beecroft, Marcus Lombard, David Mowat, Catriona McLean, Anita Cairns, Mark Davis, Nigel G Laing, and Gianina Ravenscroft. Genetics of neuromuscular fetal akinesia in the genomics era. Journal of Medical Genetics, 55:505-514, Jun 2018. URL: https://doi.org/10.1136/jmedgenet-2018-105266, doi:10.1136/jmedgenet-2018-105266. This article has 50 citations and is from a domain leading peer-reviewed journal.
(laquerriere2014mutationsincntnap1 pages 1-2): A. Laquérriere, J. Maluenda, Adrien Camus, Laura Fontenas, K. Dieterich, F. Nolent, Jie Zhou, N. Monnier, P. Latour, D. Gentil, D. Heron, I. Desguerres, P. Landrieu, C. Bénéteau, Benoit Delaporte, C. Bellesme, C. Baumann, Y. Capri, A. Goldenberg, S. Lyonnet, D. Bonneau, B. Estournet, S. Quijano-roy, C. Francannet, S. Odent, Marie-Hélène Saint-Frison, S. Sigaudy, D. Figarella-Branger, A. Gelot, J. Mussini, C. Lacroix, V. Drouin‐Garraud, M. Malinge, T. Attié-Bitach, B. Bessières, M. Bonnière, F. Encha-Razavi, A. Beaufrère, S. Khung-Savatovsky, M. Perez, A. Vasiljevic, S. Mercier, J. Roume, L. Trestard, P. Saugier-Veber, M. Cordier, V. Layet, M. Legendre, A. Vigouroux-Castera, J. Lunardi, M. Bayés, P. Jouk, L. Rigonnot, M. Granier, D. Sternberg, J. Warszawski, I. Gut, M. Gonzalès, Marcel Tawk, and J. Melki. Mutations in cntnap1 and adcy6 are responsible for severe arthrogryposis multiplex congenita with axoglial defects. Human molecular genetics, 23 9:2279-89, May 2014. URL: https://doi.org/10.1093/hmg/ddt618, doi:10.1093/hmg/ddt618. This article has 135 citations and is from a domain leading peer-reviewed journal.
(agolini2020expandingtheclinical pages 1-6): Emanuele Agolini, Claudio Cherchi, Emanuele Bellacchio, Diego Martinelli, Dario Cocciadiferro, Renato Cutrera, Maria B. Chiarini Testa, Chiara Barone, Sebastiano Bianca, and Antonio Novelli. Expanding the clinical and molecular spectrum of lethal congenital contracture syndrome 8 associated with biallelic variants of adcy6. Feb 2020. URL: https://doi.org/10.1111/cge.13691, doi:10.1111/cge.13691. This article has 11 citations and is from a peer-reviewed journal.
(liu2023novelvariantsof pages 1-2): Fang Liu, Liying Dai, Zhi Li, and Xiaowei Yin’s. Novel variants of nek9 associated with neonatal arthrogryposis: two case reports and a literature review. Frontiers in Genetics, Jan 2023. URL: https://doi.org/10.3389/fgene.2022.989215, doi:10.3389/fgene.2022.989215. This article has 4 citations and is from a peer-reviewed journal.
(yamamoto2021nek9regulatesprimary pages 1-2): Yasuhiro Yamamoto, Haruka Chino, Satoshi Tsukamoto, Koji L. Ode, Hiroki R. Ueda, and Noboru Mizushima. Nek9 regulates primary cilia formation by acting as a selective autophagy adaptor for myh9/myosin iia. Nature Communications, Jun 2021. URL: https://doi.org/10.1038/s41467-021-23599-7, doi:10.1038/s41467-021-23599-7. This article has 65 citations and is from a highest quality peer-reviewed journal.
(liu2023novelvariantsof pages 2-5): Fang Liu, Liying Dai, Zhi Li, and Xiaowei Yin’s. Novel variants of nek9 associated with neonatal arthrogryposis: two case reports and a literature review. Frontiers in Genetics, Jan 2023. URL: https://doi.org/10.3389/fgene.2022.989215, doi:10.3389/fgene.2022.989215. This article has 4 citations and is from a peer-reviewed journal.
(mis2020thelatestfads pages 1-2): Emily K. Mis, Samir Al‐Ali, Weizhen Ji, Michele Spencer‐Manzon, Monica Konstantino, Mustafa K. Khokha, Lauren Jeffries, and Saquib A. Lakhani. The latest fads: functional analysis of gldn patient variants and classification of gldn‐associated amc as a type of viable fetal akinesia deformation sequence. American Journal of Medical Genetics Part A, 182:2291-2296, Aug 2020. URL: https://doi.org/10.1002/ajmg.a.61783, doi:10.1002/ajmg.a.61783. This article has 9 citations.
(choi2024globalcarrierfrequency pages 6-8): Won-Jun Choi, Soo-Hyun Kim, Sung Rok Lee, Seung-Hun Oh, Seung Woo Kim, Ha Young Shin, and Hyung Jun Park. Global carrier frequency and predicted genetic prevalence of patients with pathogenic sequence variants in autosomal recessive genetic neuromuscular diseases. Scientific Reports, Feb 2024. URL: https://doi.org/10.1038/s41598-024-54413-1, doi:10.1038/s41598-024-54413-1. This article has 11 citations and is from a peer-reviewed journal.
(illes2024heterogenicgeneticbackground pages 1-2): Anett Illés, Henriett Pikó, Virág Bartek, Olívia Szepesi, Gábor Rudas, Zsófia Benkő, Ágnes Harmath, János Pál Kósa, and Artúr Beke. Heterogenic genetic background of distal arthrogryposis—review of the literature and case report. Jul 2024. URL: https://doi.org/10.3390/children11070861, doi:10.3390/children11070861. This article has 5 citations.
(falb2023bialleliclossoffunctionvariants pages 9-9): Ruth J Falb, Amelie J Müller, Wolfram Klein, Mona Grimmel, Ute Grasshoff, Stephanie Spranger, Petra Stöbe, Darja Gauck, Alma Kuechler, Nicola Dikow, Eva M C Schwaibold, Christoph Schmidt, Luisa Averdunk, Rebecca Buchert, Tilman Heinrich, Natalia Prodan, Joohyun Park, Martin Kehrer, Marc Sturm, Olga Kelemen, Silke Hartmann, Denise Horn, Dirk Emmerich, Nina Hirt, Armin Neumann, Glen Kristiansen, Ulrich Gembruch, Susanne Haen, Reiner Siebert, Sabine Hentze, Markus Hoopmann, Stephan Ossowski, Stephan Waldmüller, Stefanie Beck-Wödl, Dieter Gläser, Ismail Tekesin, Felix Distelmaier, Olaf Riess, Karl-Oliver Kagan, Andreas Dufke, and Tobias B Haack. Bi-allelic loss-of-function variants in kif21a cause severe fetal akinesia with arthrogryposis multiplex. Journal of Medical Genetics, 60:48-56, Nov 2023. URL: https://doi.org/10.1136/jmedgenet-2021-108064, doi:10.1136/jmedgenet-2021-108064. This article has 48 citations and is from a domain leading peer-reviewed journal.

Artifacts

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Reference Validation

Checked with linkml-reference-validator 0.2.1.

Outcome	Count
References checked	13
Resolved	13
Unresolved (possible confabulation)	0
Unverifiable	0
References weighed for topical relevance	13
On topic	9
Off topic	1

References that may not be about this subject

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

DOI:10.1038/s41467-021-23599-7 (3 mentions) - NEK9 regulates primary cilia formation by acting as a selective autophagy adaptor for MYH9/myosin IIA
shared terms: none

Weighed against this report's own most characteristic terms: disease, fetal, gene, clinical, genetic, include, variant, contracture, type, arthrogryposis, congenital, molecular, akinesia, affected, function, severe, lethal, respiratory, patient, lccs.

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

Term Validation

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

Outcome	Count
Terms checked	32
Resolved	32
Unresolved (possible confabulation)	0
Obsolete	0
Unverifiable	0
Terms whose name was checked	6
Terms named correctly	3
Terms named as a different term	0
Terms whose name is worth a second look	3

Terms whose name is worth a second look

The report's name for these is recognisably related to the term's own name without being one of them. A loose paraphrase reads the same way as a citation of the wrong sibling term - and so does a related synonym, which the ontology records precisely because it names something adjacent rather than the same thing - so these are listed rather than judged:

GO:0006413 (1 mention) - the report calls it "translation initiation"; GO calls it translational initiation, and lists "translation initiation" among its other names
GO:0006415 (1 mention) - the report calls it "translation termination"; GO calls it translational termination, and lists "translation termination" among its other names
GO:0021675 (1 mention) - the report calls it "motor neuron development"; GO calls it nerve development

Every term resolved, and every label the report gave matched.

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Lethal Congenital Contracture Syndrome: Research Report

Executive summary

1. Disease information

Definition and scope

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2. Etiology and risk/protective factors

3. Phenotypes

4. Genetic and molecular information

5. Environmental information

6. Mechanism and pathophysiology

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