Most Likely Diagnosis: Autosomal Dominant Nonsyndromic Hearing Loss
Given bilateral flat sensorineural hearing loss with a clear family history of progressive hearing loss developing in teenage years across multiple relatives, the most likely diagnosis is autosomal dominant nonsyndromic hearing loss, not Usher syndrome or the other options listed.
Clinical Reasoning
Why Autosomal Dominant Nonsyndromic HL is Most Likely
Family history pattern is diagnostic: Multiple relatives developing hearing loss in teenage years indicates an autosomal dominant inheritance pattern, which accounts for approximately 15% of genetic hearing loss cases 1
Progressive onset in adolescence: The history of progressive hearing loss beginning in teenage years is characteristic of autosomal dominant forms, which often present with later onset compared to autosomal recessive forms 1
Flat audiometric configuration: While flat configuration can occur in various etiologies, when combined with the strong family history and teenage onset, it points toward hereditary nonsyndromic hearing loss rather than syndromic causes 1
Why NOT Usher Syndrome (Option A)
Usher syndrome requires visual impairment: Usher syndrome is defined by the combination of hearing loss AND progressive vision loss (retinitis pigmentosa) 2, 3
The question provides no visual symptoms: There is no mention of night blindness, tunnel vision, or any ophthalmologic findings that would be expected in Usher syndrome 2, 3
Usher syndrome type 1 presents congenitally: The most common form (Type 1) presents with profound congenital deafness and vestibular dysfunction, not progressive teenage-onset hearing loss 3
Even when considering all deaf-blind etiologies, Usher syndrome represented only 329 of 10,000 cases, with at least 70 other causes documented 2
Why NOT the Other Options
Strial degeneration (Option B): This is a form of presbycusis (age-related hearing loss) affecting elderly patients, not teenagers with family history 1
Syphilis (Option C): Congenital syphilis would present earlier and lacks the specific family history pattern described; acquired syphilis in teenagers would be unusual and typically presents with other systemic findings 1
Autoimmune hearing loss (Option D): This typically presents as rapidly progressive, fluctuating hearing loss, often unilateral or asymmetric, and does not follow clear hereditary patterns across generations 4
Neural presbycusis (Option E): This is age-related hearing loss affecting the auditory nerve in elderly patients, completely inconsistent with teenage onset 1
Key Diagnostic Pitfall to Avoid
Do not assume Usher syndrome simply because of bilateral SNHL with family history 2. The absence of visual symptoms or vestibular dysfunction makes Usher syndrome unlikely. A comprehensive evaluation including ophthalmologic examination with electroretinogram (ERG) would be needed to diagnose Usher syndrome 3, and the question provides no such findings.
Recommended Diagnostic Approach
Obtain detailed three-generation pedigree focusing on age of onset, progression pattern, and any associated features in affected relatives 1
Perform comprehensive audiometric assessment documenting severity, configuration, symmetry, and any progression over time 1
Complete physical examination specifically looking for syndromic features (pigmentary anomalies, facial dysmorphism, skeletal abnormalities) that would suggest syndromic rather than nonsyndromic hearing loss 1
Genetic testing with comprehensive HL gene panel should be offered, as the diagnostic yield for hereditary hearing loss is approximately 40% with NGS panels 1
Ophthalmologic evaluation should still be performed to definitively rule out Usher syndrome, even though it is not the leading diagnosis based on the clinical presentation 2, 3