Nonsyndromic HL Flashcards
Otosclerosis
Autosomal dominant inheritance pattern (incomplete penetrance and variable expressivity)
More commonly presents as complex genetic disorder (mix of genetics, environment, etc)
Disease of abnormal bone remodeling/metabolism in the otic capsule
Audiologic features:
- conductive hearing loss
- mean age of onset is around 20 to 30 yrs
Connexin (Cx) Deafness
Autosomal recessive inheritance pattern
Connexin 26 is a protein product of gene GJB2
Mutation (deletion) in this gene disrupts gap junction causing poor ion transportation/cellular communication (affects potassium channel in the inner ear)
Audiological features:
- congenital HL
- mild to profound HL depending on genotype
- typically bilateral
- can be progressive or sudden
- some cases report vertigo or tinnitus
- in some syndromic variations, they have reported skin issues making CI candidacy unlikely
X-linked Congenital Stapes Fixation with Perilymph Gusher
X-linked inheritance pattern
Disorder where perilymph leaks from oval window
Audiologic features:
- mixed hearing loss (may be progressive)
- sudden loss of perilymph and hearing if inner ear surgery is conducted when mistaken for otosclerosis
Aminoglycoside-induced Toxicity
Mitochondrial inheritance pattern
Mutation that causes hearing loss if aminoglycoside is taken
Audiologic features:
- permanent severe to profound SNHL (generally not progressive), preventable
