case_images: PMC11834861_01
case_images: PMC11834861_02
case_images: PMC11834861_03
case_images: A) Electropherogram showing the T-to-C transition of the
  nucleotide 1325 (c.T1325>C) causing a methionine to threonine
  substitution at codon 442 (exon 10) of the TRbeta gene (p.M442T)
  in the index case. B) Audiogram of patients A
  (a), B (b) and C (c),
  respectively. Graphical representation of hearing thresholds. On the
  abscissa frequencies in hertz; in the order of intensities
  researched until reaching the minimum audibility threshold for each
  frequency (from -10db, to 120 db); right ear represented by the
  symbol O connected by a solid line, and left ear symbol X connected
  by a dashed line. X and O represent air conduction, and when
  together with brackets represents bone conduction reaching the
  cochlea, they represent sensorineural hearing loss. Normality
  threshold up to 25 dB, if frequency above this value constitutes
  hearing loss. a) borderline normality. b) normal hearing. c)
  frequencies well above 25 db, configuring a hearing loss,
  predominantly in the high frequencies, characterizing a lesion in
  the cochlear base region. C) Recording of transient
  otoacoustic emissions from patients A (a), B
  (b) and C (c), respectively. Abscissa
  transient frequency in Hertz, in coordinates the response amplitude
  in dB. Analyzes the cochlear function of the right and left ear, bar
  represents amplitude, in gray color, at the base, represents the
  noise amplitude, signal-to-noise ratio (difference between the hair
  cell response and noise amplitude) must be greater than or equal to
  6 dB (V).
case_images: 2359-4292-aem-69-01-e240078-g01.jpg
case_images: PMC11834861_03_2359-4292-aem-69-01-e240078-g01.jpg
case_images: F1
case_images: A descending pattern of audiometric curves was observed, with higher frequencies slightly diminished in younger subjects (Figure 1B: a and b) and a pronounced reduction in patient C (Figure 1B: c). Figure 1C also illustrates a sensorineural hearing loss, with bilateral occurrence affecting high frequencies across different age groups. Conversely, the older individual (patient C) lacked responses, especially in the left ear, where hearing loss was more pronounced (Figure 1C: c).