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Start free with EleplanPolydactyly of a triphalangeal thumb
ORPHA:93336Morphological anomaly
Also called PPD2 · Preaxial polydactyly type 2
What it is
Polydactyly of a triphalangeal thumb or PPD2 is a form of preaxial polydactyly of fingers, a limb malformation syndrome, that is characterized by the presence of a usually opposable triphalangeal thumb with or without additional duplication of one or more skeletal components of the thumb. The thumb appearance can differ widely in shape (wedge to rectangular) or it can be deviated in the radio-ulnar plane (clinodactyly). PPD2 is also associated with systemic syndromes, including Holt-Oram syndrome and Fanconi anemia.
Key facts
- Prevalence
- 1-9 / 100 000
- Age of onset
- Antenatal
- Inheritance
- Autosomal dominant
- Classified as
- Morphological anomaly
Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.
Genes
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.
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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