Association of Waardenburg syndrome with a new mutation in the PAX3 gene: A case report and literature review.

The present case report focuses on Waardenburg syndrome (WS), which occurs with a frequency of 1/40,000 and is manifested by neurosensory deafness, pigmentation deficiencies of the skin, hair and iris of the eye, and various tissue defects originating from the neural crest. WS is a genetically heterogeneous disease classified into four clinical and genetic phenotypes. In addition, it is caused by mutations in the following genes: Paired box 3 (PAX3), Endothelin 3, Endothelin Receptor Type B, Melanocyte Inducing Transcription Factor, Snail Family Transcriptional Repressor 2 and SRY-Box Transcription Factor 10. The present study focuses mainly on the structure and function of the pax3 gene and describes the case of a 33-year-old male, in whom a thorough clinical evaluation of physical characteristics and a detailed patient and family history was performed prior to concluding that the patient had WS. To confirm the diagnosis, genetic counseling was recommended and molecular genetic testing using next generation sequencing (NGS) methods was suggested. NGS revealed a novel c.209G>A (p.Cys70Tyr) mutation in the PAX3 gene, suggesting that this method is beneficial for disease screening, genetic diagnosis and counseling. The purpose of the present report is to assess the novel PAX3 gene mutation and its association with WS by analyzing the data from the case and the existing international literature, and by presenting further documented clinical cases. The present study is important due to the discovery of a new mutation, which may contribute to the understanding of the correlation between genotypes and phenotypes, aiding the field of genetic counseling. In addition, the present research study may aid the identification of potential diagnostic and therapeutic approaches for WS.