A 35-year-old woman with bilateral otosclerosis undergoes genetic counseling. She asks about the inheritance pattern and risk to her children. Otosclerosis follows which mode of inheritance pattern with what penetrance?

• A Autosomal recessive with complete penetrance
• B Autosomal dominant with 25 to 40 percent penetrance ✓
• C X-linked dominant with 50 percent penetrance
• D Multifactorial with 60 to 80 percent penetrance

Explanation

Otosclerosis follows an autosomal dominant inheritance pattern with incomplete penetrance of approximately 25 to 40 percent. This means only about one-third to two-thirds of individuals who inherit the gene will develop clinical hearing loss. Several loci have been identified (OTSC1 through OTSC8), with COL1B1 gene association on chromosome 17q.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.