Genotype-phenotype Correlation Study in a Large Series of Patients Carrying the p.Pro51Ser (p.P51S) Variant in COCH (DFNA9): Part I-A Cross-sectional Study of Hearing Function in 111 Carriers.
Sebastien P F JanssensdeVarebeke, Julie Moyaert, Erik Fransen and 9 others
PMID 34369416WHAT IT FOUND
Hearing loss in this genetic condition starts in the 30s for women and 40s for men, progressing to profound loss.
Asymmetry between ears peaks in middle age. Hearing aids are typically needed around age 40 to 45, and cochlear implants by age 57 to 62.
Key findings
01Hearing deterioration begins earlier in female carriers, often in the third decade, compared to the fifth decade for male carriers.
02Interaural asymmetry, where hearing differs significantly between the right and left ear, is a typical feature that peaks between ages 40 and 59.
03Based on hearing thresholds, carriers are estimated to become eligible for hearing aids around age 50 for men and 48 for women, and for cochlear implants around age 59 for men and 56 for women.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study is cross-sectional, so it cannot track individual progression over time or confirm if asymmetry persists for each person across all ages. There were fewer young, presymptomatic carriers than older, symptomatic ones, which may affect the precision of early onset estimates. The analysis relied on ISO 7029 normative limits, which the authors note may be less accurate for contemporary populations due to historical noise exposure data.
The easy way to misread this
Do not assume hearing loss is absent in male carriers under age 50. The study found that apparent later onset in men is partly due to stricter statistical norms for male hearing, while actual deterioration likely begins earlier in both genders.