A de novo SFMBT1 pathogenic variant identified in a boy with Poland syndrome.

Poland syndrome is a rare developmental disorder characterized by unilateral, complete or partial, absence of the pectoralis major (and often minor) muscle, accompanied with ipsilateral hand malformations. To date, no clear genetic cause has been associated with Poland syndrome, although familial cases have been reported. We report the employment of trio exome investigation and the identification of a heterozygous de novo pathogenic variant in the SFMBT1 gene, a transcription factor associated with transcriptional repression during development, in a 14-yr-old boy with Poland syndrome. We further demonstrate by means of cDNA sequencing and western blot analysis that this variant results in SFMBT1 exon 10 skipping and a lower concentration of the SFMBT1 wild-type protein. To our knowledge, the heterozygous pathogenic SFMBT1 variant identified in association with this condition is novel as it has not been elsewhere described in the literature and it can be incorporated to the limited reported cases published.