| Disease name | Acronym | OMIM | Key synonyms / alternative names | Core phenotype triad | Inheritance | Causal gene | Key variant(s) | Key references |
|---|---|---|---|---|---|---|---|---|
| Brachyphalangy-polydactyly-tibial aplasia/hypoplasia syndrome | BPTAS | 609945 | Brachyphalangy, polydactyly and tibial aplasia syndrome; Brachyphalangy, polydactyly and absent tibiae; Brachyphalangy, feet polydactyly, absent/hypoplastic tibiae (pqac-00000000, pqac-00000005, pqac-00000007) | Tibial aplasia/hypoplasia; preaxial polydactyly/polysyndactyly (sometimes described as mirror polydactyly); brachyphalangy/brachydactyly with irregular finger length (pqac-00000000, pqac-00000001, pqac-00000003) | Historically described as autosomal dominant in pre-2023 case literature; 2023 molecular study identified de novo heterozygous pathogenic variants in affected individuals, refining recurrence risk toward mostly sporadic de novo disease with theoretical parental mosaicism not excluded (pqac-00000005, pqac-00000000) | **HMGB1** (High Mobility Group Box 1) (pqac-00000000, pqac-00000012) | De novo heterozygous C-terminal frameshift variants in the final exon of **HMGB1**; recurrent example: **NM_002128.7(HMGB1): c.556_559delGAAG; p.(Glu186Argfs*42)**; commentary also cites **p.Lys184Argfs*44** among disease-causing frameshifts that replace the acidic tail with an arginine-rich basic tail (pqac-00000000, pqac-00000010, pqac-00000011) | **Mensah et al.** *Nature* (Feb 2023), DOI: [https://doi.org/10.1038/s41586-022-05682-1](https://doi.org/10.1038/s41586-022-05682-1); **Bernardi et al.** *Am J Med Genet A* (Jul 2009), DOI: [https://doi.org/10.1002/ajmg.a.32943](https://doi.org/10.1002/ajmg.a.32943) (pqac-00000000, pqac-00000005) |


*Table: This table summarizes the key identifiers, synonyms, phenotype, inheritance, molecular etiology, and anchor references for brachyphalangy-polydactyly-tibial aplasia/hypoplasia syndrome. It is useful as a compact knowledge-base entry scaffold grounded in the 2009 clinical delineation and the 2023 genetic discovery.*