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Start free with EleplanTwin-reversed arterial perfusion sequence
ORPHA:617297Disease
Also called TRAP
What it is
A rare disorder related to monochorionic twin pregnancy characterized by complete or partial absence of cardiac development in one twin (''acardiac twin'') and blood supply of both circulations by the morphologically normal co-twin (''pump twin'') via an arterioarterial anastomosis. In most cases, the acardiac twin has well developed legs and pelvis but no cephalic pole, thoracic organs, and upper extremities. The condition is associated with a high risk of perinatal death of the pump twin due to a combination of high-output cardiac failure and polyhydramnios-related pre-term birth. Hypoxia and intrauterine growth restriction are also seen in the pump twin.
Key facts
- Age of onset
- Antenatal
- Inheritance
- Not applicable
- Classified as
- Disease
ICD-10 codes
ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.
Related health topics
Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.
Cross-references
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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