PATH-67. SHH/GLI3 SIGNALOPATHIES AND NEURO-ONCO-GENETIC COUNSELING : A TUNISIAN PEDIGREE

Abstract

Abstract Here, we present a 3-generation pedigree of a Tunisian non-consanguineous family with six offspring affected by heterogeneous forms of the GLI3-related PHS spectrum. Our aim was to assess the neuro-onco-genetic risks and provide counseling for appropriate clinical follow-up. A non-consanguineous couple was referred to our genetic counseling due to the termination of their first pregnancy, which was diagnosed with multiple congenital anomalies. An autopsy examination, including pathological and radiographic analysis, was conducted. Furthermore, a medical genetic assessment considering a family history spanning over three generations as well as cytogenetic analysis were carried out. The index case was diagnosed with GLI3-related PHS based on facial dysmorphic features, auricular malformations, and unilateral postaxial toe syndactyly, along with brain macro-calcifications. The index case's father and his brother exhibited facial dysmorphic features. Furthermore, two cousins from one of their paternal uncles presented another form, associated respectively with unilateral renal agenesis and unilateral hand agenesis. The remaining three cases, who belong to the first generation, and passed away during infancy, exhibited the same condition, associated to congenital heart defect in one of them. The heterogeneity of GLI3-related overlapping conditions (SHH/GLI3 signalopathies) result from the location of GLI3 mutations in different domains of the gene, as well as the resulting functional balance between activating and repressive forms of GLI3 during development. The report of a late diagnosis of GLI3-related PHS following the discovery of hypothalamic hamartomas as well as the description of a new nonsense germline mutation in a child with Greig syndrome and medulloblastoma, support that neuro-oncological investigation of GLI3 families could be beneficial.