Genetics

Question 1

Hearing Loss–Hidden disability

Answer 1

Most frequently occurring birth defect, people don’t realize they have a HL

NICU: higher chance of having HL 2.5/100

Question 2

HL Statistics

Answer 2

3/1000 kids born with bilateral HL

1/1000 will have 40dB or greater mild
2/1000 will have 30dB or greater
2.5-3/1000 if include unilateral

by 9 years, stats double

33 infants born every day in US with HL

Question 3

Risk Factor

Answer 3

Only 50% kids have HL associated with risk factor, 270 genes identified as being associated with HL

Question 4

Incidence per 10,000 of congenital defects/diseases

Answer 4

1. HL @ 30
2. Cleft lip/plate @ 12
3. Down syndrome @ 11

Question 5

2-3/1000 babies born with HL due to…

Answer 5

50% genetic (30% is syndromic)
25% idiopathic
25% environmental (anoxia, exposed to drugs)

Question 6

Syndromic Hearing Loss

Answer 6

Progressive HL:
Alport, NF2, Usher Type 3

Other:
BOR

congenital”
Apert, CHARGE, Jervell & Lange Nielsen, Pendred, Usher types I & 2, Waardenburg

Question 7

Alport Syndrome

Answer 7

Progressive SNHL, occuar issues, bilateral mild-severe HL can progress, affects males more

Question 8

NF2: Neurofibrotosis 2

Answer 8

slowly progresive HL, vestibular schwanomas benin tumors that cause this progressive HL–when remove tumors hearing is lost entirely and tumors come back

Question 9

Usher Type 3

Answer 9

Progressive HL, progressive loss of vision (night vision lose peripheral vision then eventually tunnel vision)

Question 10

Branchio-oto-renal (BOR)

Answer 10

any kind of HL (conductive, mixed, SNHL), kids born with outer ear malformations, mild profound kidney problems–over 90% of kids with this disease have hearing problems—-ear and kidney are first 2 pharyngeal arches

Question 11

Apert Syndrome

Answer 11

Born with HL, skeletal malformations (prominent foreheads, suken eyes), very small body, many born with spina bifida, varying degrees of cognitive impairment (typically conductive HL) more common with older parents

Question 12

CHARGE

Answer 12

colobomma of the eye (hole in iris), heart defects, coanal atresia (narrowing of nasal passage), renal problems, genitalia, ears (HL)

can lead to blindness, heart defects result in death, dialysis, debate in cochlear implant for older kids–only if parents have realistic expectations and get cardiologist to sign off

Question 13

Jervell & Lange Nielsen Syndrome

Answer 13

not long life, fainting episodes due to heart disorders, profound SNHL

Question 14

Pendred Syndrome

Answer 14

SNHL, vestibular dysfunction, thyroid problems

Question 15

Usher Types 1&2

Answer 15

Profound SNHL at birth, progressive loss of vision

Question 16

Waardenburg

Answer 16

Significant HL, wide set eyes & flattened, 2 different colored eyes, white lock of hair, cognitively intact—more physical in nature

Question 17

Nonsyndromic Hearing Loss

Answer 17

Pendred Syndrome/DFNB4
Mitochondrial
Auditory Neuropathy (AN)
Connexin

Question 18

DFNB4

Answer 18

Enlarged vestibular aqueduct, connects cochlea and vestibular portion–RED FLAG for progressive HL

more of a sudden SNHL cochlea HL then next time hearing drops a little lower and doesn’t come back to normal, fall off bike and now deaf because impact results in wipeout of cochlea—cannot play contact sports, stereoids help for a time

Question 19

Mitochondrial HL

Answer 19

finding it in small group of people in Arab-israeli (mother passes on to ALL children)

Question 20

Auditory Neuropathy/AN

Answer 20

genetic or environmental

classic symptoms: kid with normal OAEs, good HC good), leading cause we think is somewhere HC are functioning how they should but somewhere between release of NT and pickup of NT at the nerve there is a disconnect

true neuropathy means there is a problem in nerve-misnomer

normal cochlear function, abnormal neural function–any kind of hearing loss–spectrum

Question 21

Key to diagnose Auditory Neuropathy

Answer 21

Normal OAEs, Poor ability to understand speech, abnormal ABR

Question 22

Connexin 26

Answer 22

Common non-syndromic HL–ton of genetic work going into this–anywhere from mild-profound HL

in some ethnic populations 80% of HL due to this, in general population only 20% of HL—need to get a genetic workup to see if this is cause

Question 23

Acquired

Answer 23

Condition develops later in life

Question 24

Carrier

Answer 24

Unaffected individual who has one normal gene and one mutant/recessive gene

Question 25

Congenital

Answer 25

Condition present from birth

Question 26

Nonsyndromic

Answer 26

HL in absence of other medical conditions

Question 27

Syndromic HL

Answer 27

hearing deficit associated with other medical problems

Question 28

Dominant

Answer 28

Mutation in gene strong enough to make a person affected even if person also has a normal copy of gene

Question 29

Recessive

Answer 29

Mutation in gene that is not strong enough to make person affected even if person also has normal copy of gene

Question 30

What percentage of pre-lingual hereditary HL is non-syndromic

Answer 30

70%

80% is autosomal recessive
15% is autosomal dominant (tends to be progressive and milder than autosomal recessive)
2-3% is X-linked

Parents more likely to be prepared for this HL with syndrome cos it most likely runs in the family

Question 31

What percentage of pre-lingual hereditary HL is syndromic

Answer 31

30%

many are due to one mutated gene (X-linked or dominant)

Question 32

Recessive Mutation

Answer 32

Most common HL because they both have recessive gene and are very surprised when there is a child with a HL