[Genetical basis of Holt-Oram syndrome]

On the basis of literature the review of data concerning genetical ground of Holt--Oram syndrome was presented. This disease is characterized by coexistence of congenital heart malformation and osseous abnormalities of upper limbs. It has been known since 1994 that the locus of the gene responsible for Holt--Oram syndrome appearance is situated in the region 12q21-q22 of chromosome 12. In 1997 this gene was defined as the TBX5 belonging to the family T-box which codes the transcription factors during embryonic development. In the cases of familial and sporadic appearance of Holt--Oram syndrome different mutations in the TBX5 gene were described. No correlation was found between mutation type and the clinical features. It is suspected that TBX5 gene is interacting with the other ones during embryonic differentiation processes.