Alport Syndrome:
Dealing with Hearing Loss and
Advances in Technology
Abby Meyer M.D.
Assistant Professor, Pediatric Otolaryngology
Director, Lions Children’s Hearing Center
University of Minnesota Department of Otolaryngology
Sensorineural hearing loss
Hearing Loss
Childhood Hearing Loss
Genetic
50%
Syndromic
1/3
Idiopathic
25%
Nonsyndromic
2/3
Recessive 75-85%
Dominant 15-24%
X-linked 1-2%
Disease, Treatment Side
Effects, Environment
25%
CMV, Herpes, Rubella,
Syphilis, Toxoplasmosis,
Varicella, Aminoglycosides,
Exchange transfusion,
Ventilation, ECMO, Fetal
Alcohol Syndrome, Lead
poisoning, Head trauma.
Hearing Loss
Childhood Hearing Loss
Genetic
50%
Syndromic
1/3
Idiopathic
25%
Nonsyndromic
2/3
Recessive 75-85%
Dominant 15-24%
ALPORT
SYNDROME
X-linked 1-2%
Disease, Treatment Side
Effects, Environment
25%
CMV, Herpes, Rubella,
Syphilis, Toxoplasmosis,
Varicella, Aminoglycosides,
Exchange transfusion,
Ventilation, ECMO, Fetal
Alcohol Syndrome, Lead
poisoning, Head trauma.
Why is there hearing loss
associated with Alport Syndrome?
• Alport Syndrome is
caused by abnormalities
of the COL4A3,
COL4A4 or COL4A5
genes, resulting in
abnormal type IV
collagen
• Type IV collagen is
important in the
structure and function of
the basilar membrane
Characteristics of the hearing loss
seen in Alport Syndrome
• Hearing loss tends to be:
– SENSORINEURAL
– BILATERAL
– SYMMETRIC
– PROGRESSIVE DURING LATER CHILDHOOD
– MIDDLE AND/OR HIGH FREQUENCY
– VARIABLE IN DEGREE
• Most patients retain some hearing
capacity.
Hearing loss in males vs hearing loss
in females with Alport Syndrome
• Significant hearing loss is more common in
males than in females
– 55% vs 45% but in X-linked Alport Syndrome (mutation
in COL4A5), significant hearing loss develops in 8090% of affected males by the age of 40.
• In general, hearing loss in affected females
tends to occur later in life than in males.
• In general, hearing loss in females may be
relatively mild or even subclinical.
But…..
• There are no gender differences in the incidence or
course of hearing loss in autosomal recessive
Alport Syndrome.
• Hearing loss in autosomal dominant Alport
Syndrome tends to be slowly progressive and may
not develop until relatively later in life (well into
adulthood).
• Characteristics of the genetic abnormality itself can
result in different risks for hearing loss (different
ages of onset of hearing loss).
– Ex: Nonsense vs missense mutations
Management of hearing loss
• Monitoring of hearing in patients with Alport
Syndrome is vital
– Hearing loss with Alport Syndrome is never
congenital, so it will not be picked up on routine
universal newborn hearing screening.
– Audiograms every 1-2 years beginning at age 6
would be a conservative place to start.
– Hearing loss typically becomes detectable by
audiogram in late childhood (6-10 years) in boys with
X-lined Alport Syndrome and in boys and girls with
autosomal recessive Alport Syndrome.
Options
•
•
•
•
Sign language
Total communication
Cued speech
Amplification
– Hearing aids
– Cochlear implant
• Combinations of technology and various
communication can be used
Options
•
•
•
•
Sign language
Total communication
Cued speech
Amplification
–Hearing aids
–Cochlear implant
• Combinations of technology and various
communication can be used
Hearing Aids
Cochlear Implantation
• Eligibility criteria
– Bilateral moderate to severe sensorineural
hearing loss
– Age > 12 months (FDA)
• Many centers implant as young as 6 months
• No upper limit on age
– Trial of hearing aids > 6 months
• Many centers will decrease time for young children
– Present cochlear nerve
– Cochlear anomalies are NOT a contraindication
Cochlear implantation—
Postlingual deafness
• Postlingually deafened children and adults
tend to do well with cochlear implantation
• Duration of deafness correlates with postimplant performance
– Better performance with shorter duration
Cochlear implantation—
The process
• Internal device
implanted
(surgery)
• Wait 3-4 weeks
for swelling to
subside
• Lots of
programming
and therapy
Cochlear implant devices
• Parents (patient if
adult) work with
the audiologist to
choose the device
• 3 cochlear implant
manufacturers
– Cochlear
– Advanced Bionics
– Med El
Thank you