Deletion of the TWIST1 gene, detected by Multiplex Ligation Probe-dependent Amplification (MPLA) and array-CGH, was consistent with phenotype of Saethre-Chotzen syndrome.
Because of the importance of TWIST1 in the regulation of embryonic development and its relationship with SCS, along with the lack of an experimentally solved 3D structure, we performed comparative modeling for the TWIST1 bHLH region arranged into wild-type homodimers and heterodimers with E47.
By identifying an already described c.445C>T TWIST missense mutation, we were able to reassign the diagnosis of the family condition to Saethre-Chötzen syndrome.
This is a confirmatory case report providing further evidence for TWIST1 haploinsufficiency in SCS, although a possible role of PTP-oc as genetic factor underlying or at least influencing the development of craniosynostosis could not be a priori excluded.
Within this region, the TWIST1 gene encoding a transcription factor was considered as a strong candidate gene since its haploinsufficiency is responsible for the human Saethre-Chotzen syndrome, characterized by skull coronal suture synostosis.
Fibroblasts from 10 individuals each with Apert syndrome (FGFR2 substitution S252W), Muenke syndrome (FGFR3 substitution P250R), Saethre-Chotzen syndrome (various mutations in TWIST1) and non-syndromic sagittal synostosis (no mutation detected) were cultured.
We report a young girl with clinical features of Saethre-Chotzen syndrome who has a previously undescribed sequence variant in the TWIST1 gene, corresponding to p.R191M.
Because of the potential importance of this finding, we organized a multicenter study enrolling people with TWIST1 mutation confirmed SCS to determine if an increased risk of cancer is present.
A retrospective chart review was performed on patients treated at The Children's Hospital of Philadelphia with TWIST1-confirmed Saethre-Chotzen syndrome (n = 22) over 23 years (1985 to 2008).
Pathologically, Twist1 is a master regulator of epithelial-to-mesenchymal transition (EMT) and is causative of the autosomal-dominant human disease Saethre Chotzen Syndrome (SCS).
Classical SCS associated with a TWIST 1 mutation could be separated phenotypically from the Muenke phenotype on the basis of the following features: low-set frontal hairline, gross ptosis of eyelids, subnormal ear length, dilated parietal foramina, interdigital webbing, and hallux valgus or broad great toe with bifid distal phalanx.