Li-Fraumeni syndrome (LFS) is associated with the high risk of a diverse spectrum of childhood and adult-onset malignancies with a predominance of soft-tissue sarcomas, osteosarcoma, breast cancer, brain tumor, adrenocortical carcinomas, Wilms tumor, leukemia, and several other LFS-associated cancer types. This paper reports a case of a 43 years male diagnosed with undifferentiated, high-grade sarcoma. Genetic testing by Next Generation Sequencing revealed a heterozygous likely novel pathogenic germline mutation in the TP53 gene (c.323delG; p.Gly108ValfsTer15) in the proband. Post-test genetic counseling referred the family screening and the other eight family members were found to be carriers for the same variant. Thus the researchers have tried to describe the genotype-phenotype correlation for the LFS with the TP53 mutation which may have contributed to the variable phenotypes in the reported family with reduced/ incomplete penetrance. In this paper the researchers have also tried to highlight the cancer genetic counseling to detect an inherited cancer syndrome