Three sisters who carried the BRCA-1 gene mutation had a preventive mastectomy and were reconstructed with silicone breast implants. After the reconstruction all three patients developed fatigue, arthralgia, myalgia and sleep disturbances within a period of four years. Because the complaints were thought to be related to the silicone breast implants, they were advised to have the implants replaced by non-silicone gel containing Monobloc Hydrogel breast implants. After this replacement operation, all complaints improved as evaluated 2.5 years later. Since the complaints developed during the presence of silicone implants and since the reversal was observed after replacement by hydrogel implants we postulate that our patients suffered from ASIA due to silicone implants, i.e. Silicone Implant Incompatibility Syndrome (SIIS). The generation of this syndrome in three sisters suggests that the susceptibility to the development of SIIS may be genetically determined.