Ménière's disease Ménière's disease Ménière's disease (MD) is a disorder of the inner ear that is characterized by episodes of feeling like the world is spinning (vertigo), ringing in the ears (tinnitus), hearing loss, and a fullness in the ear. Typically only one ear is affected, at least initially; however, over time both ears may become involved. Episodes generally last from 20 minutes to a few hours. The time between episodes varies. Over time the hearing loss and ringing in the ears may become constant. The cause of Ménière's disease is unclear but likely involves both genetic and environmental factors. A number
Niemann–Pick disease, SMPD1-associated Niemann–Pick disease, SMPD1-associated Niemann–Pick disease, SMPD1-associated refers to two different types of Niemann–Pick disease which are associated with the SMPD1 gene. There are approximately 1,200 cases of NPA and NPB worldwide with the majority of cases being Type B or an intermediate form. Descriptions of type E and type F have been published, but they are not well characterized, and are currently classified under type B. Mutations in the SMPD1 gene cause Niemann–Pick Types A and B. This gene carries instructions for cells to produce a lysosomal enzyme called acid sphingomyelinase. Insufficient activity of the enzyme acid sphingomyelinase causes the