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Ehlers-Danlos syndrome (spondylodysplastic)
This condition disrupts the normal structure of proteoglycans, which are essential components of connective tissue. People affected typically experience short stature, skeletal changes affecting the spine and limbs, loose joints, and soft, stretchy skin. The condition is inherited in an autosomal recessive pattern.
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Overview
Ehlers-Danlos syndrome (spondylodysplastic) represents a distinct subtype within the broader family of Ehlers-Danlos syndromes, combining features of connective tissue fragility with skeletal malformations. Unlike the more common hypermobile and classical forms of Ehlers-Danlos syndrome, this variant predominantly affects skeletal development whilst also impacting skin, joints, and other connective tissues. The condition arises from disruptions in proteoglycan synthesis, which are large molecules that provide structural support and elasticity to tissues throughout the body [PMID:17230205].
The spondylodysplastic form is exceptionally rare, with only a small number of families described in medical literature worldwide. Exact prevalence figures are not well established due to its rarity, though it is considerably less common than other Ehlers-Danlos syndrome subtypes. Both males and females can be affected equally. Most cases become apparent during infancy or early childhood when growth patterns and motor development diverge from typical milestones. The condition's rarity means that many healthcare professionals may not encounter it during their careers, which can sometimes lead to diagnostic delays [PMID:28778913].
Whilst this condition presents lifelong challenges, particularly regarding mobility and skeletal complications, understanding its genetic basis has improved recognition and management. Advances in genetic testing now allow definitive diagnosis, which enables families to access appropriate monitoring and supportive care through NHS clinical genetics services.
Symptoms & clinical features
The clinical presentation of spondylodysplastic Ehlers-Danlos syndrome typically becomes evident during infancy or early childhood, though some features may not be fully apparent until later development. Short stature is a hallmark feature, with affected individuals generally remaining well below average height throughout life. This growth restriction reflects the underlying skeletal abnormalities rather than hormonal deficiencies [PMID:21394826].
Skeletal manifestations are particularly prominent and distinguishing. The spine shows characteristic abnormalities, including progressive curvature (kyphoscoliosis) that may worsen over time. Limb bones are often shortened and may show bowing, particularly affecting the forearms and lower legs. Joint hypermobility is present, meaning joints move beyond the normal range, which can lead to frequent dislocations, particularly of the shoulders, hips, and fingers. Some individuals develop joint contractures, where certain joints become stiff and difficult to fully straighten, creating a paradoxical combination of excessive mobility in some joints alongside restricted movement in others.
Skin involvement mirrors features seen in other Ehlers-Danlos syndrome types but may be somewhat milder. The skin typically feels soft, velvety, and stretches more than normal, though it generally returns to its original position. Wound healing may be delayed, and scars can become widened or thin and paper-like over time. Easy bruising is common, even from minor trauma. Facial features often include a distinctive appearance with prominent eyes, a flattened nasal bridge, and thin lips. Muscle tone may be reduced during infancy (hypotonia), which can delay motor milestones such as sitting and walking. Some individuals experience recurrent hernias or organ prolapse due to weakened connective tissue support.
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Affected organs
The skeletal system bears the most significant impact in spondylodysplastic Ehlers-Danlos syndrome. The spine frequently develops progressive curvature, which can affect posture, balance, and in severe cases, compress the spinal cord or restrict lung expansion. Long bones in the arms and legs show reduced growth and may develop abnormal curvature. The growth plates, which govern bone lengthening during childhood, appear particularly susceptible to the underlying proteoglycan deficiency. Joint structures throughout the body are affected, with weakened ligaments and tendons contributing to instability and recurrent dislocations [PMID:17230205].
Skin and soft tissues demonstrate the connective tissue fragility characteristic of Ehlers-Danlos syndromes generally. The dermis, which provides skin's structural integrity, contains reduced or abnormally structured proteoglycans, leading to its characteristic softness and extensibility. Blood vessel walls may be somewhat fragile, contributing to easy bruising, though major vascular complications are not typically prominent in this subtype. Internal connective tissue supporting organs can be weakened, occasionally leading to hernias or organ prolapse. The eyes may show some involvement, with reports of myopia or other refractive errors in some affected individuals.
Risks & severity
Clinical severity in spondylodysplastic Ehlers-Danlos syndrome varies between individuals, even among family members carrying the same genetic variant. Some people experience relatively mild skeletal changes with manageable joint hypermobility, whilst others face more significant orthopaedic complications requiring surgical intervention. Progressive spinal curvature represents one of the more serious concerns, as severe kyphoscoliosis can compromise respiratory function or cause neurological complications if the spinal cord becomes compressed [PMID:21394826].
Recurrent joint dislocations pose ongoing challenges, potentially leading to chronic pain, reduced mobility, and early-onset osteoarthritis in affected joints. The combination of joint instability and skeletal abnormalities often impacts physical function, with many individuals requiring mobility aids or adaptations to maintain independence. Fractures may occur more readily than in unaffected individuals, though bone fragility is generally less severe than in conditions primarily affecting bone mineralisation. Wound healing complications and skin fragility, whilst present, typically cause fewer medical concerns than the skeletal manifestations. Life expectancy is generally not significantly reduced, though quality of life can be substantially affected by orthopaedic complications and chronic pain.
Genetic causes
Spondylodysplastic Ehlers-Danlos syndrome results from pathogenic variants in genes encoding enzymes crucial for proteoglycan synthesis. Three genes have been identified as causative: B4GALT7, B3GALT6, and SLC39A13. Each encodes a protein involved in building or transporting components needed for proteoglycan assembly, which are large molecules providing structural support throughout connective tissues [PMID:28778913].
B4GALT7 encodes beta-1,4-galactosyltransferase 7, an enzyme that catalyses one of the initial steps in synthesising the glycosaminoglycan chains attached to proteoglycans. When B4GALT7 function is disrupted, these chains cannot form properly, resulting in proteoglycans with reduced structural capacity. Similarly, B3GALT6 encodes beta-1,3-galactosyltransferase 6, which performs a subsequent enzymatic step in the same biosynthetic pathway. Pathogenic changes in either gene impair the cell's ability to produce properly structured proteoglycans, undermining connective tissue integrity throughout the body [PMID:17230205].
SLC39A13 encodes a zinc transporter protein that moves zinc ions across cell membranes. Whilst its precise role in connective tissue biology is still being elucidated, research suggests zinc availability is critical for certain enzymes involved in extracellular matrix assembly and maintenance. Disruption of SLC39A13 function appears to compromise proteoglycan and collagen processing, leading to connective tissue abnormalities. Regardless of which gene is affected, the common endpoint involves defective extracellular matrix assembly, particularly impacting tissues requiring substantial structural support such as bone, cartilage, and ligaments.
- B3GALT6 beta-1,3-galactosyltransferase 6
- B4GALT7 beta-1,4-galactosyltransferase 7
- SLC39A13 solute carrier family 39 member 13
Inheritance pattern
Spondylodysplastic Ehlers-Danlos syndrome follows an autosomal recessive inheritance pattern. This means an individual must inherit two altered copies of the causative gene - one from each parent - to develop the condition. People carrying just one pathogenic variant alongside one typical gene copy are referred to as carriers. Carriers generally remain unaffected because the single functional gene copy produces sufficient enzyme activity to maintain normal connective tissue structure [PMID:21394826].
When both parents are carriers, each pregnancy carries a 25% (one in four) chance of producing a child with two altered copies who will develop the condition, a 50% chance of producing a carrier child, and a 25% chance of producing a child who inherits two typical gene copies. Carrier parents usually have no idea they carry a pathogenic variant until they have an affected child, as their own health remains unaffected. Once a diagnosis is confirmed in a family, genetic counselling can help relatives understand their own carrier risks and reproductive options. Carrier testing is available for at-risk family members, and prenatal or preimplantation genetic diagnosis may be options for couples planning future pregnancies.
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 spondylodysplastic Ehlers-Danlos syndrome typically begins with clinical assessment when characteristic features raise suspicion. A detailed examination documenting skeletal abnormalities, joint hypermobility (often measured using the Beighton score), skin characteristics, and growth patterns helps distinguish this condition from other skeletal dysplasias or Ehlers-Danlos syndrome subtypes. Skeletal radiographs reveal distinctive bone changes, including shortened long bones, spinal abnormalities, and characteristic changes to bone shape and density.
Definitive diagnosis requires genetic testing to identify pathogenic variants in B4GALT7, B3GALT6, or SLC39A13. Within the NHS, testing is accessed through clinical genetics services following referral from a paediatrician, orthopaedic specialist, or general practitioner who suspects the diagnosis. The condition is typically evaluated under the NHS Genomic Medicine Service skeletal dysplasia testing pathway (R100-series). Genetic testing usually involves sequencing the three known causative genes to identify pathogenic variants. Identification of two pathogenic variants (one inherited from each parent) confirms the diagnosis and enables cascade testing for family members. Genetic counselling accompanies testing to ensure families understand implications for the affected individual and relatives.
Management & lifestyle
Management of spondylodysplastic Ehlers-Danlos syndrome focuses on monitoring for complications, providing supportive interventions, and optimising quality of life. No cure currently exists, and treatment remains symptomatic and preventative. A multidisciplinary approach typically involves orthopaedic specialists, physiotherapists, occupational therapists, and pain management services, coordinated through local NHS services with input from clinical genetics when needed.
Orthopaedic surveillance monitors spinal curvature progression, as significant kyphoscoliosis may require bracing or, in severe cases, surgical correction to prevent respiratory compromise or neurological damage. Joint instability is managed primarily through physiotherapy focusing on strengthening muscles around hypermobile joints to improve stability and reduce dislocation frequency. Protective strategies, such as avoiding high-impact activities and using supportive bracing for particularly unstable joints, help prevent injury. Pain management may involve analgesics, with NHS guidance typically recommending non-opioid approaches for chronic musculoskeletal pain, favouring physical therapy and, where appropriate, psychological pain management strategies [PMID:28778913].
Skin care emphasises wound protection and appropriate management of injuries to minimise scarring. Individuals are typically advised to avoid contact sports and activities carrying high injury risk. Occupational therapy assessments can identify helpful adaptations for daily living, educational settings, or workplace environments. Genetic counselling provides families with information about inheritance, recurrence risks, and testing options for relatives. Regular review allows healthcare teams to identify emerging complications early and adjust management strategies accordingly. Whilst evidence for specific dietary or supplement interventions remains limited, maintaining overall health through balanced nutrition and appropriate exercise within individual capabilities supports general wellbeing.
UK care pathway
Within the NHS, individuals with suspected spondylodysplastic Ehlers-Danlos syndrome typically enter care pathways through paediatric services when features emerge during childhood, or through adult medicine if diagnosis occurs later. Referral to clinical genetics services enables specialist assessment, genetic testing, and ongoing management planning. The NHS Genomic Medicine Service facilitates access to genetic testing through various pathways, with skeletal dysplasia and connective tissue disorder gene panels potentially capturing the causative genes depending on clinical presentation.
Following genetic confirmation, care coordination may involve multiple specialties. Orthopaedic services monitor skeletal complications, whilst physiotherapy and occupational therapy services provide ongoing functional support. Genetic counsellors within clinical genetics departments offer guidance about inheritance, family planning, and testing for relatives. Patient advocacy organisations, though limited specifically for this rare subtype, can connect families with broader Ehlers-Danlos syndrome support networks. Regular multidisciplinary review, typically coordinated through paediatric or adult medicine depending on age, ensures comprehensive monitoring and timely intervention for emerging complications.
Frequently asked questions
Will my child's height improve with growth hormone treatment?
Short stature in spondylodysplastic Ehlers-Danlos syndrome results from skeletal abnormalities rather than growth hormone deficiency, so growth hormone treatment is unlikely to be beneficial. The underlying issue involves how bones form and grow, not the hormones controlling growth. Discuss your child's growth with their paediatric team for individualised guidance.
Can my other children or future children have this condition?
If both parents are carriers of a pathogenic variant in the same gene, each pregnancy has a 25% chance of resulting in an affected child. Genetic counselling can clarify your family's specific risks, and carrier testing for partners or family members is available. Prenatal testing or preimplantation genetic diagnosis may be options for future pregnancies.
Are there activities my child should avoid?
Generally, contact sports and high-impact activities carry increased injury risk due to joint instability and bone fragility. However, appropriate physical activity within your child's capabilities is important for maintaining muscle strength and overall health. Physiotherapists can recommend suitable activities and adaptations that balance safety with physical development.
Will the spinal curvature continue to worsen throughout life?
Spinal curvature progression varies between individuals. Some people experience stable curves after skeletal maturity, whilst others show ongoing progression. Regular monitoring through orthopaedic services allows early identification of worsening curvature, enabling timely intervention such as bracing or, when necessary, surgical correction to prevent complications.
Is this condition life-threatening?
Spondylodysplastic Ehlers-Danlos syndrome is generally not life-threatening, and life expectancy is typically normal. However, severe spinal curvature can occasionally compromise breathing or cause neurological complications if untreated. Regular monitoring and appropriate management of complications help maintain good health and quality of life throughout adulthood.
References
- Demir E, Öncül Ü, Havan M. Coexistence of spinocerebellar ataxia autosomal recessive type 21 and Ehlers-Danlos syndrome spondylodysplastic type 3 in a patient. Clinical dysmorphology. 2023. PMID: 36503921
- Shoji M, Ohashi T, Nagase S. Possible involvement of zinc transporter ZIP13 in myogenic differentiation. Scientific reports. 2024. PMID: 38609428
- Kumps C, Campos-Xavier B, Hilhorst-Hofstee Y. The Connective Tissue Disorder Associated with Recessive Variants in the SLC39A13 Zinc Transporter Gene (Spondylo-Dysplastic Ehlers-Danlos Syndrome Type 3): Insights from Four Novel Patients and Follow-Up on Two Original Cases. Genes. 2020. PMID: 32295219
- Ben-Mahmoud A, Ben-Salem S, Al-Sorkhy M. A B3GALT6 variant in patient originally described as Al-Gazali syndrome and implicating the endoplasmic reticulum quality control in the mechanism of some β3GalT6-pathy mutations. Clinical genetics. 2018. PMID: 29443383
- Yoshigai E, Hara T, Hashimoto M. ZIP13 marks muscle satellite cells and contributes to their quiescent and active phase balance. Scientific reports. 2025. PMID: 40097560