Short answer · Medically reviewed summary · Last updated: 2026-05-08
Holt-Oram syndrome is a rare genetic disorder characterized by abnormalities of the upper limbs and congenital heart defects. It is caused by mutations in the TBX5 gene and follows an autosomal dominant inheritance pattern, meaning it can be passed from a single affected parent to their child. What are the primary symptoms of Holt-Oram syndrome? The hallmark of Holt-Oram syndrome involves skeletal abnormalities in the upper limbs—ranging from subtle thumb malformations to the complete absence of forearm bones—and cardiac issues.
What is Holt Oram Syndrome
What is Holt Oram Syndrome? Plain-language, medically reviewed definition plus the lived reality told by patients.
Holt-Oram syndrome is a rare genetic disorder characterized by abnormalities of the upper limbs and congenital heart defects. It is caused by mutations in the TBX5 gene and follows an autosomal dominant inheritance pattern, meaning it can be passed from a single affected parent to their child.
What are the primary symptoms of Holt-Oram syndrome?
The hallmark of Holt-Oram syndrome involves skeletal abnormalities in the upper limbs—ranging from subtle thumb malformations to the complete absence of forearm bones—and cardiac issues. Approximately 85% of individuals with Holt-Oram syndrome experience heart defects, most commonly atrial or ventricular septal defects and electrical conduction system disturbances (arrhythmias).
How common is Holt-Oram syndrome?
Holt-Oram syndrome is rare, with an estimated prevalence of 1 in 100,000 live births. Because the severity of symptoms varies significantly among individuals, some cases may remain undiagnosed for years. Within our DiseaseMaps community, 76 people with Holt-Oram syndrome have joined to share their lived experiences and clinical journeys.
What causes this condition?
Holt-Oram syndrome is caused by a pathogenic variant in the TBX5 gene, which is essential for the development of both the heart and the upper limbs during embryonic growth. While it is an inherited condition, approximately 40% of cases occur due to a "de novo" or spontaneous mutation in a person with no family history of the disease.
Key clinical features
- Upper limb defects: Often asymmetric, affecting the thumb, radius, or carpal bones.
- Congenital heart disease: Septal defects are the most frequent structural anomaly.
- Cardiac conduction disease: Issues such as bradycardia or atrial fibrillation can occur even in the absence of structural heart defects.
Next steps
- Consult a clinical geneticist to discuss genetic testing and family planning.
- Schedule a baseline evaluation with a pediatric or adult cardiologist specialized in congenital heart disease.
- Join the DiseaseMaps Holt-Oram syndrome community to connect with others navigating similar clinical paths.
Medical disclaimer: This information is for educational purposes and should not replace professional medical advice, diagnosis, or treatment.
References
- NIH Genetic and Rare Diseases Information Center (GARD): Holt-Oram syndrome
- Orphanet: Rare Disease Database (ORPHA:408)
- OMIM (Online Mendelian Inheritance in Man): #142900
