Heterozygotes with severe TWIST2 mutations found in SS patients that eliminate the both the bHLH and C-terminal domains may have syndromic manifestations [7,11,13], such as mild dysmorphic features and only bitemporal scars (p.Gln65*, [7]) or distichiasis of the upper eyelids and partial absence of lower eyelids (pS57AfsX45, [11]). This evidence concerns the gene TWIST2 and synovial sarcoma.