Double heterozygosity for and in breast cancer: considerations in surveillance and cancer risk management.

This case report examines a premenopausal woman in her 30s with double heterozygosity (DH) for and The patient's DH led her parents to undergo genetic testing as well, and new carriers were found, highlighting the importance of genetic counselling and surveillance for the entire family. Due to the rarity of DH, cancer risk and optimal surveillance strategies are not addressed in current guidelines or other sources. This report summarises existing evidence and highlights the need for further research to better understand cancer risks and to develop effective management strategies for individuals with this unique genetic profile.