title: A novel GLI3c.750delC truncation mutation in a multiplex Greig cephalopolysyndactyly syndrome family with an unusual phenotypic combination in a patient.
abstract: Greig cephalopolysyndactyly (GCPS) syndrome is an autosomal dominant disorder with high penetrance in majority of cases, characterized by a triad of polysyndactyly, macrocephaly and hypertelorism. GCPS is known to be caused by mutations in the transcription factor GLI3 gene (7p13) which results in functional haploinsufficiency of this gene. The present study reports a large multiplex family having 12 members affected with GCPS in 3 generations and several unaffected members showing autosomal dominant pattern of inheritance with complete penetrance. Interestingly an affected member of the family had unusual features including thumb which is although biphalangeal (confirmed with X-ray) but morphologically looks like finger and a unilateral tiny bony outgrown (externally indistinguishable) on the distal phalanx of the first toe of the left foot. This member also presented with mild ichthyosis. Although it is also possible that one or more of these features are coincidentally present in this member and might not be part of GCPS. Resequencing of the GLI3 gene detected a novel frame-shift mutation c.750delC in heterozygous state transmitting in the family and co-segregating with the disorder suggesting it to be the causal for the GCPS phenotype in the family. In silico analysis suggests that this mutation creates a truncated GLI3 protein resulting in its haploinsufficiency leading to GCPS syndrome. Furthermore, genotype-phenotype correlation is supported by the mutation as it lies in the amino terminal domain of the protein.
authors.affiliation: Centre for Genetic Disorders, Faculty of Science, Banaras Hindu University, Varanasi, India.
authors.forename: Rashmi
authors.initials: R
authors.lastname: Patel
authors.affiliation: Swami Harshankranand Ji Hospital & Research Center, Varanasi, India.
authors.forename: Fanish Mani
authors.initials: FM
authors.lastname: Tripathi
authors.affiliation: G S Memorial Plastic Surgery Hospital & Trauma Center, Varanasi, India.
authors.forename: Subodh Kumar
authors.initials: SK
authors.lastname: Singh
authors.affiliation: Department of Obstetrics & Gynaecology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India.
authors.forename: Anjali
authors.initials: A
authors.lastname: Rani
authors.affiliation: Department of Plastic Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India.
authors.forename: Visweswar
authors.initials: V
authors.lastname: Bhattacharya
authors.affiliation: Centre for Genetic Disorders, Faculty of Science, Banaras Hindu University, Varanasi 221005, U.P., India.
authors.forename: Akhtar
authors.initials: A
authors.lastname: Ali
keywords: Cephalopolysyndactyly; GCPS; GLI3; India; Limb defects