Overview
XYLT1-CDG, also known as Desbuquois dysplasia type 2 or xylosyltransferase 1 deficiency, is a very rare inherited condition that belongs to a group of disorders called congenital disorders of glycosylation (CDG). It is caused by changes (mutations) in the XYLT1 gene, which provides instructions for making an enzyme called xylosyltransferase 1. This enzyme plays a key role in building proteoglycans — important molecules that help form cartilage, bone, and connective tissues throughout the body. Because this enzyme does not work properly, people with XYLT1-CDG typically have significant skeletal problems. These can include short stature, joint looseness (hypermobility), dislocated joints, a flat face, and hand abnormalities such as short fingers. Many affected individuals also experience intellectual disability, developmental delays, and distinctive facial features. Some patients may have additional findings such as obesity and advanced bone age. There is currently no cure for XYLT1-CDG. Treatment focuses on managing symptoms and may include orthopedic care for skeletal problems, physical therapy to support mobility, and educational support for developmental delays. A team of specialists typically works together to address the various aspects of this condition. Early diagnosis and intervention can help improve quality of life, though the condition is lifelong and requires ongoing medical follow-up.
Key symptoms:
Short statureJoint looseness or hypermobilityDislocated jointsFlat facial appearanceShort fingers or hand abnormalitiesIntellectual disabilityDevelopmental delaysAdvanced bone ageObesity or tendency to gain weightDistinctive facial featuresScoliosis or spinal curvatureDelayed speech developmentWide-set eyesFlat nasal bridgeLoose or stretchy skin
Clinical phenotype terms (29)— 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 XYLT1-CDG.
View clinical trials →Clinical Trials
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Specialists
View all specialists →No specialists are currently listed for XYLT1-CDG.
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 XYLT1-CDG.
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.How severe is my child's condition compared to other known cases of XYLT1-CDG?,What specific skeletal problems should we watch for as my child grows?,How often should we schedule orthopedic and developmental evaluations?,Are there any activities or movements we should avoid to protect the joints?,What educational supports and therapies do you recommend starting now?,Should other family members be tested to see if they are carriers?,Are there any clinical trials or research studies we could participate in?
Common questions about XYLT1-CDG
What is XYLT1-CDG?
XYLT1-CDG, also known as Desbuquois dysplasia type 2 or xylosyltransferase 1 deficiency, is a very rare inherited condition that belongs to a group of disorders called congenital disorders of glycosylation (CDG). It is caused by changes (mutations) in the XYLT1 gene, which provides instructions for making an enzyme called xylosyltransferase 1. This enzyme plays a key role in building proteoglycans — important molecules that help form cartilage, bone, and connective tissues throughout the body. Because this enzyme does not work properly, people with XYLT1-CDG typically have significant skeleta
How is XYLT1-CDG inherited?
XYLT1-CDG follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does XYLT1-CDG typically begin?
Typical onset of XYLT1-CDG is neonatal. Age of onset can vary across affected individuals.