Disease Directory Diastrophic Dysplasia
Connective Tissue

Diastrophic Dysplasia

Also known as: DTD, diastrophic nanism, SLC26A2 dysplasia

Prevalence

1 in 100,000 (higher in Finland due to founder effect)

Onset

Congenital

Type

Genetic — autosomal recessive

Gene

SLC26A2

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 stature Joint contractures of knees, hips, and elbows Cauliflower ear deformity from auricular swelling in infancy Cervical kyphosis with risk of cervical cord compression Progressive scoliosis

Clinical Trial Eligibility Tips

What to know before applying to Diastrophic Dysplasia trials.

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.

Patient Resources

Patient Organization

Coalition for Skeletal Dysplasias

Visit website ↗

Orphanet

European reference resource for rare diseases (ORPHA:628)

View on Orphanet ↗

NORD

National Organization for Rare Disorders

Search NORD ↗

Find recruiting Diastrophic Dysplasia trials

Search 500,000+ studies from ClinicalTrials.gov, filtered for Diastrophic Dysplasia. Updated daily.

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