Overview
Atelosteogenesis type II (AO2) is a very rare and severe bone disorder that affects how the skeleton forms before birth. It is also sometimes called diastrophic dysplasia-like syndrome or de la Chapelle dysplasia. In this condition, the bones of the body — especially the limbs, spine, and chest — do not develop properly, leading to very short limbs, an unusually small chest, and serious problems with the spine and joints. The word 'atelosteogenesis' means 'incomplete bone formation,' which describes exactly what happens in this disease. Babies with AO2 are typically identified before or at birth because of their very distinctive appearance: extremely short arms and legs, a narrow chest, and characteristic facial features. The chest is often so small that the lungs cannot grow large enough to support breathing, which is the most life-threatening aspect of the condition. Many affected babies are stillborn or do not survive the newborn period due to severe breathing difficulties. AO2 is caused by changes (mutations) in the SLC26A2 gene, which helps the body build healthy cartilage and bone. There is currently no cure for AO2. Treatment focuses on supporting breathing and managing complications. Because this condition is so severe, care is usually provided by a large team of specialists working together to support the baby and family.
Also known as:
Key symptoms:
Extremely short arms and legs present from birthVery narrow, small chest that restricts breathingSevere breathing problems due to underdeveloped lungsAbnormal curvature or instability of the spine (scoliosis or kyphosis)Clubfoot (feet turned inward)Hitchhiker thumb (thumb that points away from the hand at an unusual angle)Cleft palate (opening in the roof of the mouth)Flat or underdeveloped facial featuresAbnormal or missing bones in the hands and feetJoint dislocations or stiffnessSoft, underdeveloped cartilage throughout the bodySwollen or deformed ear cartilage
Clinical phenotype terms (50)— hover any for plain English
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Neonatal
Begins at or shortly after birth (first 4 weeks)
Treatments
No FDA-approved treatments are currently listed for Atelosteogenesis type II.
View clinical trials →Clinical Trials
View all trials with filters →No actively recruiting trials found for Atelosteogenesis type II at this time.
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Specialists
View all specialists →No specialists are currently listed for Atelosteogenesis type II.
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Atelosteogenesis type II.
Community
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What does the genetic test result mean for our family, and what is the chance this could happen in a future pregnancy?,What are our options for managing our baby's breathing difficulties, and what can we realistically expect?,What does palliative care look like for a baby with AO2, and how can we ensure our baby is comfortable?,Are there any clinical trials or research studies we should know about?,Should other family members be tested to see if they are carriers of the SLC26A2 gene change?,What support services — including counseling and grief support — are available to our family?,Can you refer us to a center or specialist with experience in skeletal dysplasias?
Common questions about Atelosteogenesis type II
What is Atelosteogenesis type II?
Atelosteogenesis type II (AO2) is a very rare and severe bone disorder that affects how the skeleton forms before birth. It is also sometimes called diastrophic dysplasia-like syndrome or de la Chapelle dysplasia. In this condition, the bones of the body — especially the limbs, spine, and chest — do not develop properly, leading to very short limbs, an unusually small chest, and serious problems with the spine and joints. The word 'atelosteogenesis' means 'incomplete bone formation,' which describes exactly what happens in this disease. Babies with AO2 are typically identified before or at bi
How is Atelosteogenesis type II inherited?
Atelosteogenesis type II follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Atelosteogenesis type II typically begin?
Typical onset of Atelosteogenesis type II is neonatal. Age of onset can vary across affected individuals.