Complex sentence: At age 20, Leclerc was diagnosed with Ménière's disease, a degenerative inner ear disorder, the symptoms of which include fluctuating hearing loss and vertigo; both her father and older sister have Ménière's disease as well.
Split into simpler sentences: At age 20, Leclerc was diagnosed with Ménière's disease, a degenerative inner ear disorder, the symptoms of which include fluctuating hearing loss and vertigo. Both her father and older sister have Ménière's disease as well.