- 3-4 finger cutaneous syndactyly (HP:0011939, a Human Phenotype Ontology term): A soft tissue continuity in the A/P axis between fingers 3 and 4. Evidence: TAS. (OMIM:174700)
- Dysplastic distal thumb phalanges with a central hole (HP:0005688, a Human Phenotype Ontology term). Evidence: TAS. (OMIM:174700)
- Congenital onset (HP:0003577, a Human Phenotype Ontology term): A phenotypic abnormality that is present at birth. Evidence: PCS. Frequency: 40/40. (PMID:10441570)
- Preaxial polydactyly (HP:0100258, a Human Phenotype Ontology term): A form of polydactyly in which the extra digit or digits are localized on the side of the thumb or great toe. Evidence: PCS. Frequency: 40/40. (PMID:10441570)
- Duplication of thumb phalanx (HP:0009942, a Human Phenotype Ontology term): Complete or partial duplication of the phalanges of the thumb. Depending on the severity, the appearance on x-ray can vary from a notched phalanx (the duplicated bone is almost completely fused with the phalanx), a partially fused appearance of the two bones (bifid), two separate bones appearing side to side, or completely duplicated phalanges (proximal and distal phalanx of the thumb and/or 1st metacarpal). In contrast to the phalanges of the digits 2-5 (proximal, middle and distal), the proximal phalanx of the thumb is embryologically equivalent to the middle phalanges of the other digits, whereas the first metacarpal is embryologically of phalangeal origin and as such equivalent to the proximal phalanges of the other digits. Evidence: IEA. (OMIM:174700)
- 1-5 toe syndactyly (HP:0010713, a Human Phenotype Ontology term): Syndactyly with fusion of toes one to five (complete syndactyly of all toes of the foot). Evidence: TAS. (OMIM:174700)
- Autosomal dominant inheritance (HP:0000006, a Human Phenotype Ontology term): 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: PCS. (PMID:10441570)
These phenotypes are associated with the disease polysyndactyly 4 (OMIM:174700, an entry in Online Mendelian Inheritance in Man).