Objective: To date, bilateral congenital absence of stapes and oval window in two members (elder brother and younger sister) of a family has not been reported previously in the literature to our knowledge. The etiology, diagnosis and management are hereby introduced and discussed.
Methods: The diagnosis was based on history, audiological examinations, high resolution CT scanning and/or the operation. The modified Lempert's fenestration operation of the horizontal semicircular canal was performed on one ear each of the elder brother and the younger sister.
Results: Postoperative hearing threshold was 25 dB for speech frequencies with a gain of 47dB for the elder brother, and hearing threshold of 28 dB with a gain of 52 dB for the younger sister. Following up one to eight years individually showed that their hearing gains were steady.
Conclusion: Patients' parents are relatives of first cousin and have two sons and one daughter. However, there are two family members suffered from bilateral congenital absence of stapes and oval window, and these malformations might be related to inheritance. Good bone conduction and Carhart's notches revealed bilaterally in the patients' audiograms. These are the important indications for diagnosis of this disease. The modified Lempert's fenestration operation of the horizontal semicircular canal is a safe and good choice for treatment.