Which condition causes the fixation of the stapes and is linked genetically?

Otosclerosis is a condition characterized by abnormal bone growth in the ear, particularly affecting the stapes bone in the middle ear. This growth leads to fixation of the stapes, which impairs its ability to vibrate properly in response to sound waves, resulting in conductive hearing loss.

Genetically, otosclerosis is known to have familial patterns, suggesting a genetic predisposition. It often runs in families, and specific genetic mutations have been identified in some cases, indicating the condition is linked to hereditary factors.

In contrast, the other conditions listed do not primarily involve fixation of the stapes nor are they notably associated with genetic inheritance. Non-suppurative and suppurative otitis media are primarily conditions related to middle ear inflammation, usually due to infections or fluid buildup, and do not typically result in fixed stapes. Otitis externa, which is an outer ear condition, primarily involves inflammation of the ear canal and does not affect the stapes. Hence, otosclerosis stands out as the correct answer due to its direct implications of stapes fixation and genetic association.