In all five children, the diagnosis of GCPS was confirmed by molecular analysis of GLI3 (two had intragenic mutations and three had complete gene deletions detected on array comparative genomic hybridisation), thus highlighting the importance of trigonocephaly or overt metopic or sagittal synostosis as a distinct presenting feature of GCPS.
A single patient with acrocallosal syndrome and a de novo p.Ala934Pro mutation in GLI3 has been reported, whereas diverse and numerous GLI3 mutations have also been described in syndromes with overlapping clinical manifestations, including Greig cephalopolysyndactyly syndrome, Pallister-Hall syndrome, trigonocephaly with craniosynostosis and polydactyly, oral-facial-digital syndrome, and non-syndromic polydactyly.
Variable phenotype in Greig cephalopolysyndactyly syndrome: clinical and radiological findings in 4 independent families and 3 sporadic cases with identified GLI3 mutations.
In two GCPS cases, both of which did not exhibit obvious cytogenetic rearrangements, point mutations were identified in different domains of the protein, showing for the first time that Greig syndrome can be caused by GLI3 point mutations.
The phenotypic spectrum of GLI3 morphopathies includes autosomal dominant preaxial polydactyly type-IV and postaxial polydactyly type-A/B; No phenotype prediction from the position of GLI3 mutations.
Mutations in different domains of the GLI3 gene underlie several congenital diseases including Greig cephalopolysyndactyly syndrome (GCPS) and Pallister-Hall syndrome (PHS).
The most important issue might be that GCPS and PHS exhibit an autosomal dominant trait, but mouse homologs, such as Pdn/Pdn, Xt(H)/Xt(H), Xt(J)/Xt(J) and Gli3(tmlUrt)/Gli3(tmlUrt), are autosomal recessive traits in the manifestation of similar phenotypes to human diseases.
Mutations in the gene encoding the zinc finger transcription factor GLI3 (GLI-Kruppel family member 3) have been identified in patients with Grieg cephalopolysyndactyly syndrome in which premature fusion of calvarial suture (craniosynostosis) is an infrequent but important feature.
Variable phenotype in Greig cephalopolysyndactyly syndrome: clinical and radiological findings in 4 independent families and 3 sporadic cases with identified GLI3 mutations.
In two GCPS cases, both of which did not exhibit obvious cytogenetic rearrangements, point mutations were identified in different domains of the protein, showing for the first time that Greig syndrome can be caused by GLI3 point mutations.
A novel syndrome, combining features of CCM and GCPS, can be added to the group of entities that result from deleterious genetic variants involving GLI3, including GCPS, acrocallosal syndrome, Pallister-Hall syndrome, and contiguous gene syndrome.
Since others have excluded GLI3 in ACS, we suggest that ACS may represent a heterogeneous group of disorders that, in some cases, may result from a mutation in GLI3 and represent a severe, allelic form of GCPS.
Human GLI3 gene mutations have been identified in several phenotypes of digital abnormality such as Greig cephalopolysyndactyly syndrome, Pallister-Hall syndrome, preaxial polydactyly type-IV (PPD-IV) and postaxial polydactyly.
Large deletions or translocations resulting in haploinsufficiency of the GLI3 gene have been associated with Greig cephalopolysyndactyly syndrome (GCPS; M175700) although no mutations have been identified in GCPS patients with normal karyotypes.
Mutations in GLI3 lead to the development of the human Greig cephalopolysyndactyly syndrome (GCPS) and the mouse mutations extra toes (Xt) and anterior digit deformity (add).
Our findings fully support previous genotype-phenotype correlations, showing that exonic deletions, missense mutations, as well as truncating variants localised out of the middle third of the GLI3 gene result in GCPS/PPD-IV and not PHS.