Connective Tissue

Diastrophic Dysplasia

Also known as DTD, diastrophic nanism, SLC26A2 dysplasia

Diastrophic dysplasia is a severe skeletal dysplasia caused by biallelic loss-of-function variants in SLC26A2, encoding a sulfate transporter essential for proteoglycan sulfation in cartilage, resulting in defective extracellular matrix in

ORPHA:628 ↗Gene SLC26A2Prevalence 1 in 100,000 (higher in Finland due to founder effect)Onset CongenitalGenetic — autosomal recessive

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studies recruiting now

as of 7 Sept 2026

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studies registered in total

as of 7 Sept 2026

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countries with a recruiting site

as of 7 Sept 2026

None

recruiting study posted to date

among recruiting studies

Recruiting trials

No registered studies found for Diastrophic Dysplasia.

ClinicalTrials.gov has no study listed under this name as of 7 Sept 2026. That can change, and there are other routes worth knowing about.

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Coalition for Skeletal DysplasiasPatient association
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About Diastrophic Dysplasia

Diastrophic dysplasia is a severe skeletal dysplasia caused by biallelic loss-of-function variants in SLC26A2, encoding a sulfate transporter essential for proteoglycan sulfation in cartilage, resulting in defective extracellular matrix in developing bone and cartilage. It is characterised by rhizomelic short stature, severe club feet, hand abnormalities including a characteristic hitchhiker thumb, joint contractures, and cervical kyphosis that poses a significant risk of spinal cord compression. Progressive scoliosis and hip dislocation are common complications requiring surgical management.

Common clinical features

Severe bilateral club feet (talipes equinovarus)Characteristic hitchhiker thumb (abducted and proximally placed)Rhizomelic short statureJoint contractures of knees, hips, and elbowsCauliflower ear deformity from auricular swelling in infancyCervical kyphosis with risk of cervical cord compressionProgressive scoliosis

From Orphanet’s phenotype annotations (CC BY 4.0). Not a complete list.

Before you apply

Things trial teams commonly ask about for Diastrophic Dysplasia. Not eligibility rules; those are set by each study.

  • Cervical spine imaging (flexion-extension radiographs and MRI) is typically required at baseline given the high risk of cervicomedullary compression — this is both a safety screen and a disease-severity measure.
  • Surgical history (club foot correction, joint surgery, spinal fusion) must be fully documented as prior operations affect mobility endpoints used in trial assessments.
  • Molecular confirmation of biallelic SLC26A2 pathogenic variants is required; this gene also underlies achondrogenesis type 1B and atelosteogenesis type 2, so phenotypic and molecular classification together are needed.

Related conditions

Information, not medical advice. Trial listings are shown as recorded on ClinicalTrials.gov; whether any study is right for you is a decision for you and your clinicians, and eligibility is decided by each research team. Disease information from Orphanet (CC BY 4.0).