Phenotypes associated with the disease polydactyly of an index finger (OMIM:174600):
- Triphalangeal thumb (HP:0001199): A thumb with three phalanges in a single, proximo-distal axis. Thus, this term applies if the thumb has an accessory phalanx, leading to a digit like appearance of the thumb. Evidence: IEA. (OMIM:174600)
- Preaxial polydactyly (HP:0100258): A form of polydactyly in which the extra digit or digits are localized on the side of the thumb or great toe. Evidence: TAS. (OMIM:174600)
- Autosomal dominant inheritance (HP:0000006): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele. Evidence: IEA. (OMIM:174600)