Overview
X-linked acrogigantism (X-LAG) due to Xq26 microduplication is a very rare condition that causes extreme overgrowth, particularly excessive height, beginning in early childhood. This condition has been reclassified (marked as 'obsolete' under this specific Orphanet entry) and is now generally referred to as X-linked acrogigantism or X-LAG syndrome. It is caused by a small duplication of genetic material on the X chromosome in the region called Xq26, which includes the GPR101 gene. This gene duplication leads to overproduction of growth hormone (GH) and insulin-like growth factor 1 (IGF-1), resulting in gigantism — meaning children grow much faster and taller than expected for their age. Symptoms typically begin in infancy or early childhood and include rapid growth in height, enlarged hands and feet, coarsening of facial features, and increased appetite. Some children may also develop a pituitary tumor (usually a pituitary adenoma or hyperplasia) that produces excess growth hormone. If untreated, the excessive growth continues and can lead to significant complications including joint problems, cardiovascular strain, and metabolic issues. Treatment focuses on controlling growth hormone levels. Options include medications such as somatostatin analogs (like octreotide or lanreotide) and growth hormone receptor antagonists (like pegvisomant). In some cases, surgery to remove a pituitary tumor or even radiation therapy may be needed. Early diagnosis and treatment are important to manage growth and prevent long-term complications.
Also known as:
Key symptoms:
Extremely rapid growth in height starting in infancy or early childhoodVery tall stature for age (gigantism)Enlarged hands and feetCoarsening of facial featuresIncreased appetite and excessive hungerPituitary gland enlargement or tumorExcessive sweatingThickened soft tissuesJoint pain or stiffnessHeadachesIncreased head circumferenceAcne or oily skinSleep disturbances or sleep apneaEarly puberty or delayed puberty depending on the case
X-linked dominant
Carried on the X chromosome; a single copy can cause the condition
Infantile
Begins in infancy, roughly 1 month to 2 years old
Treatments
No FDA-approved treatments are currently listed for OBSOLETE: X-linked acrogigantism due to Xq26 microduplication.
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Specialists
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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 OBSOLETE: X-linked acrogigantism due to Xq26 microduplication.
Community
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
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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 is my child's current growth hormone level, and what is the target we are aiming for?,Which treatment approach do you recommend first — medication, surgery, or a combination?,How often will my child need blood tests and MRI scans to monitor the condition?,What are the potential side effects of the medications being prescribed?,Should we consider genetic counseling for our family, and what is the chance of this happening in future children?,Are there any clinical trials or new treatments being studied for X-LAG?,What support services are available to help my child with the emotional and social aspects of this condition?
Common questions about OBSOLETE: X-linked acrogigantism due to Xq26 microduplication
What is OBSOLETE: X-linked acrogigantism due to Xq26 microduplication?
X-linked acrogigantism (X-LAG) due to Xq26 microduplication is a very rare condition that causes extreme overgrowth, particularly excessive height, beginning in early childhood. This condition has been reclassified (marked as 'obsolete' under this specific Orphanet entry) and is now generally referred to as X-linked acrogigantism or X-LAG syndrome. It is caused by a small duplication of genetic material on the X chromosome in the region called Xq26, which includes the GPR101 gene. This gene duplication leads to overproduction of growth hormone (GH) and insulin-like growth factor 1 (IGF-1), res
How is OBSOLETE: X-linked acrogigantism due to Xq26 microduplication inherited?
OBSOLETE: X-linked acrogigantism due to Xq26 microduplication follows a x-linked dominant inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does OBSOLETE: X-linked acrogigantism due to Xq26 microduplication typically begin?
Typical onset of OBSOLETE: X-linked acrogigantism due to Xq26 microduplication is infantile. Age of onset can vary across affected individuals.