Hecht Beals syndrome

Hecht-Beals Syndrome: A Comprehensive Review

Introduction

Hecht-Beals syndrome, also known as congenital contractural arachnodactyly (CCA), represents a rare autosomal dominant connective tissue disorder that was first described by Beals and Hecht in 1971. The syndrome is characterized by a distinctive constellation of clinical features including multiple joint contractures, arachnodactyly (long, slender fingers and toes), kyphoscoliosis, and crumpled ear helices. While CCA shares phenotypic similarities with Marfan syndrome (MFS), it is caused by mutations in a different gene and generally has a more favorable prognosis.^{[1][2][3][4][5][6]}

It is important to distinguish Hecht-Beals syndrome (congenital contractural arachnodactyly) from trismus-pseudocamptodactyly syndrome (also called Hecht syndrome or distal arthrogryposis type 7), as these are two distinct conditions despite occasional confusion in nomenclature.^[7][8][9]

Epidemiology

Hecht-Beals syndrome is an extremely rare disorder with an estimated incidence of less than 1 in 10,000 individuals per year. The prevalence is difficult to establish precisely due to the rarity of the condition and phenotypic overlap with other connective tissue disorders. Approximately 70 probands with molecularly confirmed diagnoses have been described in the medical literature. The condition affects males and females equally and occurs in all ethnic groups and geographic regions without predilection.^[10][11][12]

Etiology and Genetic Basis

FBN2 Gene Mutations

Hecht-Beals syndrome is caused by pathogenic variants in the FBN2 gene located on chromosome 5q23. The FBN2 gene encodes fibrillin-2, a large glycoprotein of approximately 2,912 amino acids and 350 kDa molecular weight. Fibrillin-2 is an essential component of microfibrils in the extracellular matrix and plays critical roles in connective tissue structure and elastogenesis.^{[4][13][14][15][16][17][1]}

The inheritance pattern is autosomal dominant, meaning a single copy of the mutated gene is sufficient to cause the disorder. Most cases result from new (de novo) mutations, though familial transmission with variable expressivity has been documented.^{[5][6][18][1][4]}

Types of Mutations

Disease-causing mutations in FBN2 predominantly include:^{[13][19][20][21][22]}

• Missense mutations: Most commonly involve substitution of cysteine residues with other amino acids, disrupting disulfide bond formation in calcium-binding epidermal growth factor-like (cbEGF-like) domains^[22][16]
• Splice site mutations: Lead to aberrant mRNA splicing and exon skipping^[19][20][11]
• In-frame deletions: Result in removal of critical amino acid sequences while preserving the reading frame^[23][24]

Approximately 75% of identified mutations cluster in a critical “neonatal region” spanning exons 24-35 of the FBN2 gene, which encodes the central stretch of cbEGF-like domains. Interestingly, unlike FBN1 mutations in Marfan syndrome, FBN2 mutations rarely alter the calcium-binding consensus sequence itself.^[25][26][22]

Pathophysiology

The molecular pathogenesis of Hecht-Beals syndrome involves two primary mechanisms:^[15][16]

1. Structural deficiency: Reduced production or abnormal structure of fibrillin-2 protein leads to decreased formation of microfibrils, weakening elastic fibers in connective tissue throughout the body^[16]
2. TGF-β dysregulation: Fibrillin-2 normally sequesters transforming growth factor-beta (TGF-β) in the extracellular matrix. Deficient fibrillin-2 causes inappropriate activation and overactivation of TGF-β signaling pathways, contributing to skeletal, cardiovascular, and other manifestations^[27][17][16]

Clinical Features

The clinical presentation of Hecht-Beals syndrome is heterogeneous, with significant variability in severity even among affected family members.^[6][18][28]

Musculoskeletal Manifestations

The hallmark features involve the musculoskeletal system:^{[4][5][6][10]}

Major Criteria:

• Congenital joint contractures: Permanent flexion contractures affecting elbows, knees, hips, ankles, and fingers, present at birth. These contractures often improve spontaneously with age but rarely resolve completely^{[2][5][6][10]}
• Arachnodactyly: Abnormally long, slender fingers and toes^[1][2][5][4]
• Camptodactyly: Permanently flexed fingers, particularly at the proximal interphalangeal joints^[5][10][4]
• Kyphoscoliosis: Progressive front-to-back and side-to-side spinal curvature affecting approximately 50% of patients. This is often the most serious complication requiring surgical intervention^[29][6][10]

Additional Skeletal Features:

• Dolichostenomelia (disproportionately long limbs)^[30][10]
• Muscular hypoplasia, especially of calf muscles^[3][31][5]
• Pectus carinatum (protruding chest) or pectus excavatum (sunken chest)^[10][30]
• Narrow body habitus and tall stature^[3][4]
• Talipes equinovarus (clubfoot)^[5]

Craniofacial Features

• Crumpled ear helices: A distinctive and highly specific feature described as folded or wrinkled appearance of the outer ear. This finding helps differentiate CCA from Marfan syndrome and tends to improve with age^{[18][2][4][10][5]}
• High-arched palate^[31]
• Micrognathia (small jaw) in some cases^[32]
• Facial asymmetry may be present^[31]

Cardiovascular Complications

While cardiovascular involvement in Hecht-Beals syndrome is less common and typically less severe than in Marfan syndrome, cardiac monitoring is essential:^[6][30][5]

• Mitral valve prolapse: Reported in a subset of patients^[30][6][5]
• Aortic root dilatation: Occurs rarely but requires surveillance^[6][10][5]
• Congenital heart defects: Atrial septal defects, ventricular septal defects, and transient cardiomyopathy have been documented in severe cases^[33][34]
• Mitral regurgitation^[30][6]

The risk of severe cardiovascular complications, including aortic dissection, is estimated to be low compared to Marfan syndrome, but the exact risk remains incompletely characterized.^[10][30]

Ophthalmologic Features

Ocular complications occur in approximately 20% of CCA patients but are generally less severe than in Marfan syndrome:^[18][5]

• Heterotropia (strabismus)^[33]
• Blue sclerae^[35]
• Myopia^[5]
• Keratoconus^[10]
• Glaucoma, cataracts, and lens coloboma (reported rarely)^[36][35]

Notably, ectopia lentis (lens dislocation), a cardinal feature of Marfan syndrome, has not been confirmed in individuals with molecularly proven Hecht-Beals syndrome.^[18][10]

Neonatal and Severe Forms

A severe neonatal form of CCA has been described, characterized by:^{[37][34][2][36]}

• Early-onset severe contractures
• Significant cardiovascular malformations
• Gastrointestinal abnormalities (intestinal atresia, malrotation)
• High mortality in early infancy due to multisystem complications^[34][37]

The neonatal form typically results from new mutations and demonstrates more severe phenotypic expression.^[2]

Differential Diagnosis

Accurate diagnosis is essential for appropriate management and genetic counseling. The primary conditions to consider in the differential diagnosis include:^{[38][39][31][18]}

Marfan Syndrome

Marfan syndrome shares many skeletal features with Hecht-Beals syndrome but differs in several critical aspects:^{[4][31][6][18][5]}

Similarities:

• Marfanoid habitus (tall, slender build)
• Arachnodactyly
• Kyphoscoliosis
• Pectus deformities

Key Distinguishing Features:

• Genetic basis: Marfan syndrome is caused by FBN1 mutations (fibrillin-1), while CCA results from FBN2 mutations (fibrillin-2)^[4][18]
• Contractures: Congenital joint contractures are characteristic of CCA but not typical of Marfan syndrome^[6][18][5]
• Crumpled ears: Highly specific for CCA; absent in classic Marfan syndrome^[40][18]
• Ectopia lentis: Present in 60% of Marfan patients; extremely rare or absent in molecularly confirmed CCA^[18][10]
• Cardiovascular risk: Progressive aortic root dilatation and high risk of dissection are hallmarks of Marfan syndrome; cardiovascular involvement in CCA is less frequent and typically less severe^[40][6][18]

Interestingly, the original patient described by Dr. Antoine Marfan in 1898 is now believed to have had congenital contractural arachnodactyly rather than Marfan syndrome.^[18]

Trismus-Pseudocamptodactyly Syndrome (Hecht Syndrome)

This distinct condition is sometimes confused with Hecht-Beals syndrome due to overlapping nomenclature:^{[8][9][41][7]}

• Also called: Distal arthrogryposis type 7, Dutch-Kentucky syndrome^[42][43][8]
• Genetic cause: Caused by mutations in MYH8 gene (myosin heavy chain 8) on chromosome 17p13.1, not FBN2^[43][7][42]
• Key features: Inability to fully open the mouth (trismus) and pseudocamptodactyly (finger flexion only with wrist dorsiflexion)^{[9][44][8][42]}
• Prevalence: Approximately 60 cases reported worldwide^[7]
• Inheritance: Autosomal dominant with a recurrent founder mutation (p.R674Q) in MYH8^[42]

Other Connective Tissue Disorders

• Loeys-Dietz syndrome: Features arterial aneurysms, hypertelorism, and cleft palate^[5]
• Ehlers-Danlos syndrome: Characterized by joint hypermobility, skin hyperextensibility, and tissue fragility^[39]
• Homocystinuria: Includes intellectual disability, ectopia lentis, and thromboembolism^[39][5]
• Stickler syndrome: Involves progressive myopia, retinal detachment, and early-onset arthritis^[39]

Diagnosis

Clinical Diagnosis

The diagnosis of Hecht-Beals syndrome is primarily clinical, based on characteristic physical findings. In 2020, Meerschaut et al. developed a validated 20-point clinical scoring system to aid in diagnosis:^{[45][46][47][30][5]}

CCA Clinical Scoring System Components (scored based on prevalence):

• Arachnodactyly
• Camptodactyly
• Large joint contractures
• Crumpled ears
• Dolichostenomelia
• Kyphoscoliosis
• Pectus deformities
• Muscular hypoplasia
• Craniofacial features

Interpretation:

• Total score ≥7: Likely CCA (high probability)
• Total score <7: Unlikely CCA (low probability)

This scoring system showed significant discrimination between FBN2-positive and FBN2-negative patients (P < 0.001) and provides a quantitative tool for clinical guidance.^[46]

Molecular Genetic Testing

Genetic testing confirms the diagnosis and enables accurate genetic counseling:^[48][30]

Testing Methods:

• Targeted gene sequencing: Analysis of the FBN2 gene using Sanger sequencing or next-generation sequencing (NGS)^[14][11][49]
• Whole exome sequencing (WES): Useful for complex cases or when initial targeted testing is negative^[21][13][14]
• Deletion/duplication analysis: Detects copy number variations (CNVs) including multiexon deletions^[23]

Detection Rate:
Mutations in FBN2 are identified in approximately 75% of clinically diagnosed CCA cases when focused on the critical neonatal region (exons 24-35). The overall mutation detection rate ranges from 75-86% depending on the testing methodology and population studied.^[50][22][25]

Cardiovascular Evaluation

Due to potential cardiac involvement, systematic cardiovascular assessment is recommended:^[51][30]

• Baseline echocardiography: To evaluate aortic root dimensions, mitral valve structure and function, and identify congenital heart defects^[30][6]
• Serial monitoring: Annual or biennial echocardiograms to monitor for progressive aortic dilatation until stability is established^[6][30]
• Z-score assessment: Aortic root measurements adjusted for body surface area^[30]

Orthopedic Assessment

Comprehensive musculoskeletal evaluation includes:^[30]

• Documentation of joint contractures and range of motion
• Spinal examination for kyphoscoliosis with radiographic imaging when indicated
• Assessment of functional limitations

Ophthalmologic Examination

A complete eye examination should be performed to identify any ocular complications.^[35][5]

Management and Treatment

There is no cure for Hecht-Beals syndrome; management focuses on symptomatic treatment, monitoring for complications, and improving quality of life.^[52][53][30]

Multidisciplinary Approach

Optimal care requires coordination among multiple specialties:^[53][30]

• Medical genetics
• Orthopedics
• Cardiology
• Physical and occupational therapy
• Ophthalmology (as needed)

Musculoskeletal Management

Conservative Treatment:

• Physical therapy: Regular stretching exercises and range-of-motion activities beginning in infancy to maintain joint mobility and prevent muscle atrophy^{[54][55][56][53]}
• Occupational therapy: Focused on improving fine motor skills and activities of daily living^[57][53]
• Serial casting: For mobilization of stiff joints, particularly clubfoot deformities^[55][54]
• Splinting and bracing: Removable splints to maintain joint position and support function^[54][55]
• Ponseti method: Successful for correction of clubfoot in CCA patients^[53][55]

Surgical Interventions:
Joint contractures often improve spontaneously with age, but progressive kyphoscoliosis frequently requires surgical correction:^[29][2][6]

• Spinal fusion: For severe progressive scoliosis that impacts respiratory function or quality of life^[29]
• Soft tissue releases: Tendon lengthening or capsulotomies for severe contractures limiting function^[57][53]
• Osteotomies: Bone-shortening procedures for severe deformities^[53][57]

Recent studies indicate that scoliosis associated with Beals syndrome can present with large curves requiring extensive surgical approaches.^[29]

Cardiovascular Management

• Regular monitoring: Echocardiography every 1-2 years to assess aortic dimensions and valve function^[6][30]
• Beta-blockers or ARBs: May be considered for progressive aortic root dilatation, though evidence specific to CCA is limited^[30]
• Surgical intervention: Aortic root replacement if significant dilatation develops, following established guidelines for connective tissue disorders^[30]
• Endocarditis prophylaxis: For patients with valvular abnormalities undergoing dental or surgical procedures^[30]

Anesthetic Considerations

Patients with Hecht-Beals syndrome present unique challenges for anesthesia:^{[58][59][60][32]}

• Difficult airway: Trismus, micrognathia, and high-arched palate may complicate intubation^[58][32]
• Cardiovascular instability: Risk related to underlying cardiac abnormalities^[60][58]
• Positioning: Joint contractures may limit positioning options^[61][58]
• Careful preoperative assessment: Including echocardiography and airway evaluation^[51][58]

Genetic Counseling and Reproductive Options

Family Planning:

• Each pregnancy of an affected individual has a 50% risk of inheriting the pathogenic variant^[48]
• Parental somatic and germline mosaicism has been observed, affecting recurrence risk counseling^[18]

Prenatal Testing:
When a disease-causing FBN2 mutation is identified in the family, prenatal diagnosis is available through:^[62][63][48]

• Chorionic villus sampling (CVS) at 10-12 weeks gestation
• Amniocentesis at 15-18 weeks gestation
• Preimplantation genetic testing (PGT)

Prenatal ultrasound may demonstrate joint contractures and hypokinesia in suspected cases.^[48][10]

Prognosis and Natural History

The prognosis for Hecht-Beals syndrome is generally favorable, particularly when compared to Marfan syndrome:^[2][40][5]

Course of Disease:

• Joint contractures: Often improve spontaneously during childhood and adolescence, though rarely resolve completely^[2][10][6]
• Crumpled ears: Tend to improve with age^[10][18]
• Kyphoscoliosis: Often progressive and may worsen over time, representing the most serious long-term complication^[2][29][6]
• Cardiovascular: The vast majority of patients have isolated musculoskeletal features that improve with age, with low risk of life-threatening cardiovascular complications^[6][30]

Mortality:

• Most individuals with classic CCA have normal lifespan^[40][5]
• The severe neonatal form is associated with high early mortality due to cardiovascular and gastrointestinal complications^[37][34][2]

Quality of Life:
With appropriate physical therapy, orthopedic management, and cardiovascular monitoring, most affected individuals can achieve good functional outcomes and independence.^[54][53]

Recent Advances

Molecular Understanding

Recent research has expanded understanding of FBN2 pathophysiology:^[24][27]

• Identification of novel mutation types including multiexon deletions^[23]
• Recognition that missense mutations can affect protein structure without disrupting splicing^[21]
• Evidence of redox homeostasis breakdown contributing to thoracic aortic aneurysm formation in affected patients^[27]

Diagnostic Tools

The development and validation of the clinical scoring system by Meerschaut et al. represents a significant advance in standardizing diagnosis and facilitating research.^[45][46]

Therapeutic Implications

Understanding the role of TGF-β dysregulation in CCA pathogenesis opens potential therapeutic avenues, including TGF-β antagonists that are being studied in related fibrillinopathies.^[38]

Conclusion

Hecht-Beals syndrome (congenital contractural arachnodactyly) is a rare autosomal dominant connective tissue disorder caused by mutations in the FBN2 gene. The syndrome is characterized by congenital joint contractures, arachnodactyly, crumpled ears, and kyphoscoliosis. While it shares phenotypic similarities with Marfan syndrome, CCA generally has a more favorable prognosis with less severe cardiovascular involvement. Diagnosis relies on clinical evaluation aided by validated scoring systems, with molecular confirmation available through genetic testing. Management involves multidisciplinary care including physical therapy, orthopedic interventions for progressive scoliosis, and cardiovascular monitoring. With appropriate treatment, most affected individuals can achieve good functional outcomes and normal lifespan. Genetic counseling is essential for families, with prenatal testing available when disease-causing mutations are identified. Ongoing research continues to expand understanding of the molecular pathophysiology and may lead to targeted therapeutic interventions in the future.

References

References are provided inline throughout the article using citation numbers [1-134] corresponding to the medical literature sources reviewed, including publications from:

• PubMed Central/NCBI
• National Organization for Rare Disorders (NORD)
• Orphanet
• GeneReviews (NCBI Bookshelf)
• MedlinePlus Genetics
• The Marfan Foundation
• Peer-reviewed medical journals including Genetics in Medicine, Human Molecular Genetics, Frontiers in Genetics, American Journal of Medical Genetics, and others

Sources

1. https://pmc.ncbi.nlm.nih.gov/articles/PMC4873217/   
2. https://pubmed.ncbi.nlm.nih.gov/25493702/          
3. https://pubmed.ncbi.nlm.nih.gov/12144083/  
4. https://en.wikipedia.org/wiki/Congenital_contractural_arachnodactyly         
5. https://rarediseases.org/rare-diseases/congenital-contractural-arachnodactyly/                     
6. https://marfan.org/conditions/beals-syndrome/                   
7. https://en.wikipedia.org/wiki/Trismus_pseudocamptodactyly_syndrome   
8. https://pmc.ncbi.nlm.nih.gov/articles/PMC3787647/   
9. https://rarediseases.org/rare-diseases/trismus-pseudocamptodactyly-syndrome/  
10. https://www.orpha.net/en/disease/detail/115               
11. https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2020.00143/full  
12. http://info.marfan.org/hubfs/Resource_Downloads/Beals_Syndrome.pdf
13. https://pmc.ncbi.nlm.nih.gov/articles/PMC11795632/  
14. https://pmc.ncbi.nlm.nih.gov/articles/PMC8123754/  
15. https://www.creative-biolabs.com/gene-therapy/fbn2-and-associated-diseases.htm 
16. https://medlineplus.gov/genetics/gene/fbn2/    
17. https://www.nature.com/articles/s41598-023-33886-6 
18. https://pmc.ncbi.nlm.nih.gov/articles/PMC1524931/              
19. https://pmc.ncbi.nlm.nih.gov/articles/PMC7058790/ 
20. https://pmc.ncbi.nlm.nih.gov/articles/PMC11289072/ 
21. https://pubmed.ncbi.nlm.nih.gov/39911746/  
22. https://pubmed.ncbi.nlm.nih.gov/11754102/   
23. https://pmc.ncbi.nlm.nih.gov/articles/PMC8826123/  
24. https://www.nature.com/articles/s41439-024-00264-1 
25. https://www.sciencedirect.com/science/article/pii/S2214426925000084 
26. https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2022.804202/full
27. https://www.nature.com/articles/s41598-025-03135-z  
28. https://pmc.ncbi.nlm.nih.gov/articles/PMC11414699/
29. https://pubmed.ncbi.nlm.nih.gov/39466540/    
30. https://marfan.org/wp-content/uploads/2021/01/Beals_Syndrome.pdf                   
31. https://pmc.ncbi.nlm.nih.gov/articles/PMC1050028/    
32. https://storage.googleapis.com/jnl-sljo-j-slja-files/journals/1/articles/7326/submission/proof/7326-1-27884-1-10-20150109.pdf  
33. https://casereports.bmj.com/content/14/3/e237904 
34. https://www.nature.com/articles/pr1974730   
35. https://hasekidergisi.com/articles/congenital-contractural-arachnodactyly-beals-hecht-syndrome-a-case-report/6117  
36. https://www.ejbms.net/download/congenital-contractural-arachnodactyly-two-unrelated-newborns-with-novel-clinical-findings-9181.pdf 
37. https://pubmed.ncbi.nlm.nih.gov/16531736/  
38. https://pmc.ncbi.nlm.nih.gov/articles/PMC3542934/ 
39. https://en.wikipedia.org/wiki/Marfan_syndrome   
40. https://gpnotebook.com/pages/orthopaedics/beals-hecht-syndrome   
41. https://www.sciencedirect.com/science/article/pii/S1348864318300089
42. https://onlinelibrary.wiley.com/doi/abs/10.1002/ajmg.a.31495   
43. https://zfin.org/DOID:0111603 
44. https://www.orpha.net/en/disease/detail/3377
45. https://www.sciencedirect.com/science/article/pii/S1098360021011047 
46. https://pubmed.ncbi.nlm.nih.gov/31316167/  
47. https://www.zora.uzh.ch/entities/publication/341847e7-df98-4dfa-a0ad-a0be175b049b
48. https://onlinelibrary.wiley.com/doi/full/10.1002/mgg3.1638   
49. https://dnalabsindia.com/test/fbn2-gene-contractural-arachnodactyly-congenital-ngs-genetic-dna-test
50. https://onlinelibrary.wiley.com/doi/10.1002/mgg3.2482
51. https://www.journalajst.com/sites/default/files/issues-pdf/10131.pdf 
52. https://www.medicoverhospitals.in/diseases/congenital-contractural-arachnodactyly/
53. https://pmc.ncbi.nlm.nih.gov/articles/PMC7330016/       
54. https://rarediseases.org/rare-diseases/arthrogryposis-multiplex-congenita/   
55. https://posna.org/physician-education/study-guide/arthrogryposis   
56. https://www.orthopaedicmanipulation.com/beals-syndrome/
57. https://www.physio-pedia.com/Arthrogryposis_Multiplex_Congenita  
58. https://pmc.ncbi.nlm.nih.gov/articles/PMC8016048/    
59. http://slja.sljol.info/articles/10.4038/slja.v28i2.8518/galley/6427/download/
60. https://www.cureus.com/articles/332924-labor-analgesia-in-a-patient-with-beals-syndrome-a-case-report-of-management-challenges 
61. https://jmc.elmerpub.com/index.php/jmc/article/download/5157/149
62. https://pubmed.ncbi.nlm.nih.gov/10464661/
63. https://www.liebertpub.com/doi/pdf/10.1089/gte.1997.1.293
64. https://academic.oup.com/ehjcr/advance-article-pdf/doi/10.1093/ehjcr/ytad631/54716879/ytad631.pdf
65. https://pmc.ncbi.nlm.nih.gov/articles/PMC6894034/
66. https://www.mdpi.com/2075-4418/12/11/2868/pdf?version=1668844355
67. https://archivesofrheumatology.org/full-text-pdf/673
68. https://www.medicoverhospitals.in/diseases/beals-syndrome/
69. https://www.cureus.com/articles/43239-a-36-year-old-female-with-congenital-contractural-arachnodactyly-and-pectus-excavatum-requiring-fourth-time-redo-surgical-correction
70. https://pmc.ncbi.nlm.nih.gov/articles/PMC9261969/
71. https://pmc.ncbi.nlm.nih.gov/articles/PMC10720308/
72. https://www.mdpi.com/1660-4601/19/2/772/pdf
73. https://pmc.ncbi.nlm.nih.gov/articles/PMC3909233/
74. https://pmc.ncbi.nlm.nih.gov/articles/PMC4484186/
75. https://pmc.ncbi.nlm.nih.gov/articles/PMC8775541/
76. https://academic.oup.com/hmg/article/23/21/5827/2900993
77. https://www.sciencedirect.com/topics/medicine-and-dentistry/fibrillin-2
78. https://www.ncbi.nlm.nih.gov/gene?Db=gene&Cmd=DetailsSearch&Term=2201
79. https://emedicine.medscape.com/article/946315-differential
80. https://www.uniprot.org/uniprotkb/P35556/entry
81. https://www.frontiersin.org/articles/10.3389/fmed.2021.627192/pdf
82. https://pmc.ncbi.nlm.nih.gov/articles/PMC7886701/
83. https://www.medsci.org/v18p2752.htm
84. https://jamanetwork.com/journals/jamapediatrics/fullarticle/505272
85. https://pmc.ncbi.nlm.nih.gov/articles/PMC8960307/
86. https://www.qeios.com/read/KXRFNQ/pdf
87. https://www.mdpi.com/2075-4418/12/10/2375/pdf?version=1664532315
88. https://academic.oup.com/hmg/article/23/19/5271/2900717
89. https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2023.1035887/full
90. http://onlinelibrary.wiley.com/doi/10.1002/ajmg.1320180210/pdf
91. https://research.rug.nl/en/publications/a-clinical-scoring-system-for-congenital-contractural-arachnodact
92. https://www.sciencedirect.com/topics/veterinary-science-and-veterinary-medicine/arachnodactyly
93. https://lirias.kuleuven.be/2823555?limo=0
94. https://journals.lww.com/10.1097/MS9.0000000000003150
95. https://pmc.ncbi.nlm.nih.gov/articles/PMC9083398/
96. https://pmc.ncbi.nlm.nih.gov/articles/PMC11911505/
97. https://pmc.ncbi.nlm.nih.gov/articles/PMC9002905/
98. https://pmc.ncbi.nlm.nih.gov/articles/PMC10806968/
99. https://onlinelibrary.wiley.com/doi/10.1111/j.1601-0825.2005.01005.x
100. https://pubmed.ncbi.nlm.nih.gov/18646717/
101. https://www.ijcasereportsandimages.com/archive/2012/003-2012-ijcri/006-03-2012-chattopadhyay/ijcri-00603201266-chattopadhyay-full-text.php
102. https://www.semanticscholar.org/paper/A-novel-presentation-of-Hecht­Beals-trismus-Review-Chattopadhyay-Philips/2de168850d705c423a9ff7d251e6984490d8c907
103. https://pmc.ncbi.nlm.nih.gov/articles/PMC11193586/
104. https://pmc.ncbi.nlm.nih.gov/articles/PMC2921290/
105. https://www.frontiersin.org/articles/10.3389/fgene.2021.768342/pdf
106. https://www.ncbi.nlm.nih.gov/medgen/78540
107. https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2021.768342/full
108. https://medlineplus.gov/genetics/condition/congenital-contractural-arachnodactyly/
109. https://www.orpha.net/en/disease/detail/319340
110. https://www.indianpediatrics.net/view-article.php?issue=6344
111. https://www.ncbi.nlm.nih.gov/books/NBK1386/
112. https://pubmed.ncbi.nlm.nih.gov/15888111/
113. https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/ccr3.1693
114. https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/mgg3.1638
115. https://www.frontiersin.org/articles/10.3389/fgene.2020.00143/pdf
116. https://www.indianpediatrics.net/dec2002/dec-1159-1161.htm
117. https://pmc.ncbi.nlm.nih.gov/articles/PMC11927799/
118. https://www.sciencedirect.com/science/article/pii/S2214426924000934
119. https://obgyn.onlinelibrary.wiley.com/doi/full/10.1002/uog.13350
120. https://febs.onlinelibrary.wiley.com/doi/10.1016/j.fob.2015.02.005
121. https://pmc.ncbi.nlm.nih.gov/articles/PMC11120833/
122. https://pmc.ncbi.nlm.nih.gov/articles/PMC2871745/
123. https://pmc.ncbi.nlm.nih.gov/articles/PMC2561939/
124. https://pmc.ncbi.nlm.nih.gov/articles/PMC315447/
125. https://pmc.ncbi.nlm.nih.gov/articles/PMC10789400/
126. https://pmc.ncbi.nlm.nih.gov/articles/PMC447610/
127. https://pmc.ncbi.nlm.nih.gov/articles/PMC8756495/
128. https://pmc.ncbi.nlm.nih.gov/articles/PMC18967/
129. https://valintermed.com/en/medlibrary/sindrom-trizma-psevdokamptodaktilii/
130. https://www.ncbi.nlm.nih.gov/clinvar/RCV000377907/
131. https://www.sickkids.ca/siteassets/care–services/for-health-care-providers/lab-information-sheets/trismus-pseudocamptodactyly-syndrome.pdf
132. http://www.malacards.org/card/arthrogryposis_distal_type_7
133. https://pmc.ncbi.nlm.nih.gov/articles/PMC2698792/
134. https://emedicine.medscape.com/article/941917-treatment
135. https://my.clevelandclinic.org/health/diseases/23190-arthrogryposis
136. https://brieflands.com/journals/thrita/articles/56280
137. https://pmc.ncbi.nlm.nih.gov/articles/PMC2847211/
138. https://pmc.ncbi.nlm.nih.gov/articles/PMC10450317/