Accessory mitral valve tissue

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Accessory mitral valve tissue

ORPHA:99061Morphological anomaly

What it is

A rare congenital non-syndromic heart malformation characterized by an accessory mitral valve leaflet or various accessory mitral valve structures. It may be asymptomatic or present at various ages with symptoms of left ventricular outflow tract obstruction, low cardiac output due to subaortic obstruction or congestive heart failure. In some cases, it may be a source of cardioembolism. The malformation may be isolated or associated with other congenital heart malformations.

Key facts

Classified as
Morphological anomaly

ICD-10 codes

Q23.8filed under a broader ICD-10 category — shared with 6 other rare diseases

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.

Cross-references

MONDO 0020402UMLS C0344774

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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