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Ehlers-Danlos syndrome (musculocontractural)
This condition results from pathogenic variants in genes that control dermatan sulphate production, a crucial component of connective tissue. It primarily affects the skin, joints, and skeletal system, leading to progressive physical limitations and increased risk of tissue fragility.
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Overview
Ehlers-Danlos syndrome (musculocontractural) represents a distinct subtype within the Ehlers-Danlos syndrome spectrum, differentiated by the presence of multiple joint contractures from birth alongside characteristic connective tissue features. Unlike other Ehlers-Danlos variants, this form specifically disrupts the biosynthesis of dermatan sulphate, a glycosaminoglycan essential for maintaining the structural integrity of connective tissues throughout the body [PMID:23375983]. The condition follows an autosomal recessive inheritance pattern and is an ultra-rare disorder, with exact prevalence figures not well established in the UK population.
Individuals with this condition typically present in infancy with a recognisable pattern of features including congenital contractures affecting multiple joints, characteristic craniofacial appearance, and skin that is both hyperextensible and fragile. The underlying biochemical defect affects the normal scaffolding that gives strength and flexibility to tissues, leading to progressive musculoskeletal complications over time. Recognition of this specific subtype is important for accurate genetic counselling and appropriate clinical management strategies.
Symptoms & clinical features
The clinical features of Ehlers-Danlos syndrome (musculocontractural) typically become apparent at birth or during early infancy. Congenital contractures represent one of the hallmark features, most commonly affecting the fingers, wrists, elbows, knees, and hips, restricting normal joint movement from the outset. These contractures may progress over time, leading to increasing mobility challenges as children grow [PMID:23375983]. Affected individuals often display distinctive craniofacial characteristics including a long, narrow face, eyes that slant downward at the outer corners, prominent eyes, and low-set ears, which may aid clinical recognition.
Skin manifestations are prominent and include marked hyperextensibility, where the skin can be stretched significantly beyond normal limits, alongside pronounced fragility that leads to easy bruising and atypical scarring. Wounds may heal slowly and produce characteristic wide, atrophic scars. Additional features often include hypotonia (reduced muscle tone) in infancy, skeletal abnormalities such as scoliosis or kyphosis that may develop or worsen with age, and foot deformities including clubfoot (talipes equinovarus). Some individuals experience recurrent joint dislocations or subluxations despite the presence of contractures in other joints, reflecting the paradoxical combination of joint stiffness in some areas and excessive laxity in others.
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Affected organs
The musculoskeletal system bears the primary clinical burden in Ehlers-Danlos syndrome (musculocontractural). Joint contractures and progressive skeletal deformities can significantly impact mobility and physical function, whilst the underlying connective tissue weakness predisposes to spinal curvature abnormalities that may require orthopaedic intervention. Muscle hypotonia in early life can affect motor development and feeding capabilities.
The skin across the entire body demonstrates abnormal properties, being both excessively stretchy and prone to tearing with minimal trauma. The dermis lacks the normal structural reinforcement provided by properly formed dermatan sulphate-containing proteoglycans, resulting in poor wound healing and abnormal scar formation. Whilst the cardiovascular system is less prominently affected than in some other Ehlers-Danlos subtypes, the generalised connective tissue abnormality means that careful clinical assessment of all organ systems is warranted, as individual cases may show variable expression of features.
Risks & severity
The severity of Ehlers-Danlos syndrome (musculocontractural) varies between individuals but generally represents a significant lifelong condition requiring ongoing medical support. The combination of joint contractures and progressive skeletal abnormalities typically results in substantial mobility limitations, with many affected individuals requiring walking aids or wheelchairs as they grow older. The degree of contracture progression appears variable, with some individuals experiencing relatively stable joint limitations whilst others show continued deterioration over time.
Skin fragility poses ongoing risks of tissue injury from routine activities, and poor wound healing can lead to complications including infection and problematic scarring. The musculoskeletal complications, particularly progressive spinal curvature, may necessitate surgical intervention in some cases. Developmental milestones may be delayed due to hypotonia and joint limitations. Importantly, cognitive development is typically unaffected, with intellectual abilities expected to be within the normal range. Life expectancy data is limited due to the condition's rarity, though some affected individuals may experience reduced life expectancy depending on the severity of complications and access to supportive care.
Genetic causes
Ehlers-Danlos syndrome (musculocontractural) is caused by pathogenic variants in either CHST14 or DSE, genes that encode enzymes critical for dermatan sulphate biosynthesis. CHST14 encodes carbohydrate sulfotransferase 14, an enzyme responsible for adding sulphate groups to dermatan sulphate chains during their synthesis. DSE encodes dermatan sulphate epimerase, which converts specific sugar residues within the glycosaminoglycan backbone to create dermatan sulphate from chondroitin sulphate [PMID:23375983]. Both enzymes function within the same biochemical pathway, explaining why variants in either gene produce a similar clinical picture.
Dermatan sulphate normally integrates into proteoglycans that form essential components of the extracellular matrix, the structural network surrounding cells in connective tissues. This matrix provides tensile strength and elasticity to skin, ligaments, tendons, and other tissues. When CHST14 or DSE function is impaired, dermatan sulphate production is reduced or the molecules produced are structurally abnormal, compromising the mechanical properties of connective tissue throughout the body. The resulting matrix cannot properly withstand normal mechanical stresses, leading to the characteristic combination of tissue fragility, abnormal joint mechanics, and progressive skeletal changes observed in affected individuals [PMID:20949506].
- CHST14 carbohydrate sulfotransferase 14
- DSE dermatan sulfate epimerase
Inheritance pattern
Ehlers-Danlos syndrome (musculocontractural) follows an autosomal recessive inheritance pattern, meaning that an affected individual must inherit one pathogenic variant from each parent to develop the condition. Parents of an affected child are typically carriers, each possessing one working copy and one non-working copy of either CHST14 or DSE. Carriers themselves generally show no features of the condition, as one functioning gene copy provides sufficient enzyme activity for normal connective tissue development.
When both parents are carriers for variants in the same gene, each pregnancy carries a 25% chance of producing an affected child, a 50% chance of producing a carrier child, and a 25% chance of producing a child with two working gene copies. Siblings of an affected individual have a two-in-three chance of being carriers if they are unaffected. Genetic counselling is important for families to understand these inheritance risks and to discuss options for family planning, including the availability of prenatal or preimplantation genetic testing in future pregnancies. Consanguinity increases the likelihood that both parents carry variants in the same recessive disease gene, making this inheritance pattern more common in populations where marriage between relatives is customary.
When both parents are carriers, each child has a 25% chance of being affected, 50% of being a carrier, and 25% of being unaffected.
Diagnosis & testing
Diagnosis of Ehlers-Danlos syndrome (musculocontractural) typically begins with clinical recognition of the characteristic constellation of features, particularly the combination of congenital contractures, distinctive facial features, and skin fragility in an infant or young child. Clinical geneticists assess the pattern of features and consider this diagnosis when the presentation differs from the more common hypermobile or classical Ehlers-Danlos subtypes. Biochemical testing of dermatan sulphate levels in urine may show abnormalities, though this is not always conclusive.
Definitive diagnosis requires genetic testing to identify pathogenic variants in CHST14 or DSE. This is typically performed through targeted gene sequencing or broader connective tissue disorder gene panels available through the NHS Genomic Medicine Service. Referral to clinical genetics is appropriate when the clinical features suggest this diagnosis, enabling access to specialist genetic counselling and testing. Whilst specific NHS R-codes for rare Ehlers-Danlos subtypes facilitate testing access, the rarity of this condition means that some clinicians may not immediately recognise the musculocontractural subtype, potentially leading to initial misdiagnosis as other contracture disorders or more common Ehlers-Danlos variants.
Management & lifestyle
Management of Ehlers-Danlos syndrome (musculocontractural) requires a multidisciplinary approach coordinated through specialist centres with expertise in connective tissue disorders. Orthopaedic monitoring is essential to assess progression of joint contractures and spinal curvature, with physiotherapy programmes designed to maintain as much joint mobility and muscle strength as feasible. Some individuals may benefit from surgical intervention for progressive scoliosis or severe contractures, though surgical planning must account for the tissue fragility and wound healing challenges inherent to the condition.
Skin care focuses on injury prevention and meticulous wound management when injuries occur. Protective measures, such as padding vulnerable areas and avoiding activities with high trauma risk, can reduce the frequency of skin injuries. When wounds do occur, careful closure techniques and extended healing times may be necessary. Regular review by dermatology or plastic surgery services experienced in connective tissue disorders can be valuable. Supportive equipment including orthotics, mobility aids, and adapted seating may improve function and comfort. Families should have access to genetic counselling to understand inheritance implications and reproductive options. Currently, no specific pharmacological treatments are available to correct the underlying enzyme deficiency, though symptomatic management of pain and optimisation of musculoskeletal function remain important therapeutic goals.
UK care pathway
Within the NHS Genomic Medicine Service, individuals suspected of having Ehlers-Danlos syndrome (musculocontractural) should be referred to clinical genetics services, typically through paediatric specialists, rheumatology, or dermatology. The National Genomic Test Directory includes testing for Ehlers-Danlos syndromes under relevant R-codes for connective tissue disorders, enabling access to comprehensive genetic panel testing that includes CHST14 and DSE alongside other Ehlers-Danlos-associated genes. This facilitates accurate subtype diagnosis, which is crucial for appropriate management and genetic counselling.
Once diagnosed, ongoing care is typically coordinated through specialist multidisciplinary clinics, which may be located at regional genetics centres or tertiary paediatric hospitals. These clinics bring together expertise from clinical genetics, orthopaedics, physiotherapy, and other relevant specialties. Genetic counsellors play a vital role in supporting families to understand the inheritance pattern, recurrence risks, and testing options for other family members. For adults with this rare condition, transition from paediatric to adult services requires careful planning to ensure continuity of specialist input, as adult services may have less familiarity with this particular Ehlers-Danlos subtype.
Frequently asked questions
Will my child's joint contractures improve with physiotherapy?
Physiotherapy can help maintain existing joint mobility and prevent further stiffness, but cannot typically reverse congenital contractures completely. Regular stretching exercises and specialist input may slow progression and optimise functional abilities, though the degree of improvement varies between individuals.
Is this the same as the hypermobile type of Ehlers-Danlos syndrome?
No, Ehlers-Danlos syndrome (musculocontractural) is a distinct subtype with different genetic causes and features. Whilst the hypermobile type involves excessive joint flexibility, the musculocontractural type is characterised by joint contractures and stiffness, alongside more pronounced skin fragility.
What is the chance of having another affected child?
If both parents are carriers of a pathogenic variant in the same gene (CHST14 or DSE), each pregnancy has a 25% chance of producing an affected child. Genetic counselling can discuss testing options for parents and reproductive choices including prenatal diagnosis.
Can adults develop this condition or does it only affect children?
The condition is present from birth due to the inherited genetic variants, so it does not develop in adulthood. However, some features may become more apparent or worsen over time, and diagnosis is sometimes delayed until childhood when the full pattern of features becomes evident.
Should family members be tested even if they have no symptoms?
Siblings of an affected individual may wish to know their carrier status, particularly for future family planning, as carriers are healthy but can pass the variant to their children. Genetic counselling can help family members decide whether testing is appropriate for their circumstances.
References
- Umapathy N, Thirugnana Sambanda Moorthy B, Azhagar Nambi Santhi V. Microcornea, cerebellar hypoplasia and hyperlax joints-unusual combo in rare Ehlers-Danlos syndrome-musculocontractural type 1. BMJ case reports. 2024. PMID: 38834308