Congenital Genetic & Non Genetic SNHL Flashcards
Approximately 70% of genetic HL is inherited in a an ____________.
autosomal recessive pattern
Approximately 15% of genetic HL is inherited in an ____________.
autosomal dominant pattern
The remaining _____ % include all the other forms of inheritance
15
Approximately 2% of genetic HL can be attributed to a__________.
X-linked pattern
3 Congenital Genetic SNHLs
- Connexin 26
- Usher syndrome
- Waardenberg syndrome
_______ is a key constituent of the gap junctions in the inner ear.
Connexin 26
When connexin 26 does not function properly due to genetic mutations, the gap junctions do not function properly and _______________.
potassium ions cannot be recycled
Gap junctions :
recycle potassium ions
Mutations of the gene that codes for Cx26 is estimated to be responsible for approximately ______ of all the recessive cases of non-syndromic congenital hearing loss.
-50%
Non-Syndromic: CONNEXIN 26 (CX26) Occurs in ______
1/2500-1/5000
Common Forms of Autosomal Recessive Syndromic SNHL:
- Usher
- Pendred
- Jervell and Lange-Nielson
This is the most common eye/ear syndrome:
Usher Syndrome
Usher Syndrome is the basis for approximately ____ of all children with ____________.
- 3-10%
- severe to profound SNHL
Characteristics/clinical findings of Usher Syndrome:
- Bilateral SNHL
- Moderate to profound
- Typically congenital
- Can be progressive
- varying problems with balance
Waardenburg Syndrome
is a Autosomal Dominant Syndromic:
What are some of the characteristics of Waardenburg Syndrome?
– Partial albinism (white forelock)
– Laterally positioned medial canthi (dystopia canthorum) – Different colored eyes (heterochromia iridis) or bright blue eyes
Hearing Loss (in a quarter of cases) caused by Waardenburg Syndrome?
– Congenital SNHL
– Slight to profound
– Unilateral or bilateral
– Varying configuration
Congenital non-genetic SNHL - Just remember TORCHS
– Toxoplasmosis – Rubella – Cytomegalovirus – Herpes Simplex Virus – Congenital Syphilis
CMV stands for:
CYTO -MEGALO- VIRUS
CMV is the and most complex member of the __________ of DNA viruses.
Herpes family
Varicella-zoster virus (VZV) —>
chicken pox and
shingles
Herpes simplex virus (HSV) —>
cold sores and genital ulcers
Epstein-Barr virus —>
infectious mononucleosis
CMV has a special impact on:
– Epithelial cells
– Ependymal cells lining the ventricles
– Organ of Corti
– Neurons of the VIII cranial nerve
In the U.S., between _______ of adults will have acquired CMV by age ____.
- 50% to 85%
- 40
_______ during pregnancy accounts for most cases of congenital CMV.
Primary maternal infection
Congenital CMV infection occurs in _____ of all live births.
0.4% to 2.3% - which is approximately 40,000 neonates a
year.
90% of CMV cases are _______ at birth
asymptomatic (appear normal)
The (Majority (85%) of these asymptomatic congenital
CMV cases will _____.
remain normal
In 15% of asymptomatic congenital CMV cases, these disabilities may develop:
• Congenital or delayed onset, progressive
sensorineural hearing loss
• Expressive language delays
• Learning disabilities
Of congenital CMV cases ___ are symptomatic at birth.
10%
CONGENITAL CMV Hearing Loss :
- SNHL
- May be unilateral or bilateral
- May be congenital or delayed onset
- May be mild to profound
- Frequently progressive
- Unpredictable configuration
30 to 60 % of CMV SNHL are ______ and affect __________.
- symptomatic
- 1200 to 2400 annually
13 to 24 % of CMV SNHL are ______ and affect ___________.
- asymptomatic
- 4600 to 8600 annually
A-CMV results in ____ times as many SNHLs as does S-CMV
2 to 7
________ CMV infection causes a number of significant problems, including hearing loss.
Congenital
To confirm congenital infection, viral testing within ______ weeks of birth is needed.
3
