27 Congenital - Ear

Question 1

Incidence of congenital hearing loss

Answer 1

1:1000

Question 2

What percent of congenital hearing loss is hereditary and what percent of those are syndromic

Answer 2

> 60% (others say 50%); 30%

Question 3

What is the typical inheritance pattern of syndromic HL

Answer 3

Auto Dom

Question 4

Typical inheritance patterns of non-syndromic HL

Answer 4

75% Auto Rec
10-20% Auto Dom
2-3% X-linked
<1% mitochondrial

Question 5

What genetic mutation is though to be responsible for 50-80% of all AR HL?

Answer 5

Mutation of the DFNB1 gene on chrom 13q encoding for connexin 26 (causes 27% of sporadic cases of congen HL)

Question 6

T/F: 1 in 31 ppl are carriers for the connexin 26 mutation

Answer 6

True

Question 7

What is function of connexin 26

Answer 7

Formation of gap jnc in stria vascularis, BM, limbus, and spiral prominence of cochlea (transports K+)

Question 8

What is the typical severity and pattern of AD HL

Answer 8

Less severe, delayed onset, high-freq HL

Question 9

What is the typical severity and pattern of X-linked HL

Answer 9

Prelingual and more clinically diverse HL

Question 10

What is term for complete agenesis of petrous portion of temporal bone

Answer 10

Michel aplasia

Question 11

What is term for developmentally deformed cochlear where only the basal coil can be identified

Answer 11

Mondini aplasia

Question 12

What is m/c form of inner ear aplasia

Answer 12

Scheibe aplasia (cochleosaccular dysplasia or pars inferior dysplasia)

Question 13

Which inner ear aplasia is characterized by high freq HL with nl low freq HL

Answer 13

Alexander

Question 14

Which inner ear aplasia will not allow cochlear implant or amplification aids

Answer 14

michel aplasia

Question 15

Mutation of what gene is a/w EVA

Answer 15

Pendrin on chrom 7q31

Question 16

What inner ear malformation is a/w early onset SNHL, usu b/l and progressive and vertigo

Answer 16

EVA

Question 17

Which SCC forms first? Last?

Answer 17

Superior canal first; lateral canal last

Question 18

T/F: Superior SCC deformities are always accompanied by lateral SCC deformities

Answer 18

True

Question 19

What syndrome accounts for m/c form of hereditary congenital deafness

Answer 19

Waardenburg’s synd (I thought it was Ushers)

Question 20

What is incidence of Waardenburg’s

Answer 20

1 in 4000

Question 21

What are the 4 clinical subtypes of Waardenburgs

Answer 21

“1. SNHL (20%), heterochromia irides, pigment anomalies, dystopia canthorum

2. As above, without dystopia canthorum (SNHL in >50%).
3. Klein–Waardenburg’s syndrome: microcephaly, mental retardation, limb and skeletal abnormalities, in addition to signs of #1.
4. Shah-Waardenburg’s syndrome: #2 + Hirschsprung’s disease

Question 22

What genetic mutation is responsible for most cases of types 1 and 3 Waardenburg’s

Answer 22

Mutation of PAX3 gene on chrom 2q37

Question 23

What is dystopia canthorum

Answer 23

Shortened and fused medial eyelids resulting in small medial sclera, lateral displacement of inferior puncta and hypertelorism

Question 24

What synd is characterized by CP, micrognathia, severe myopia, retinal detachments, marganoid habitus, and HL

Answer 24

Stickler

Question 25

What genetic mutations are responsible for most cases of Stickler synd

Answer 25

Mutations of COL2A1 gene on chrom 12 or COLIIA2 gene on chrom 6

Question 26

Synd c/b SNHL and RP

Answer 26

Usher's

Question 27

3 subtypes of Usher's

Answer 27

I—Severe–profound hearing loss, absent vestibular function, prepubertal retinitis pigmentosa. II—Moderate–severe hearing loss, normal vestibular function, postpubertal retinitis pigmentosa. III—Progressive hearing loss.

Question 28

M/c syndromic cause of HL

Answer 28

Pendred synd, accounting for 10% of cases

Question 29

What inner ear malformations are more common in pts with Pendred

Answer 29

Mondini aplasia and EVA

Question 30

What gene is a/w both Pendred synd and EVA

Answer 30

PDS gene, encoding for pendrin protein, on chrom 7q31

Question 31

What are the clinical features of Alport synd

Answer 31

SNHL and renal failure (presenting as hematuria)

Question 32

What is basic defect causing Alport

Answer 32

Mutation of COL4A5 gene producing the alpha chain of Type IV collage in BM

Question 33

What syndrome is c/b HL, renal defects, and cervical fistulas

Answer 33

BOR (branchiootorenal)

Question 34

What is inheritance of BOR

Answer 34

Auto Dom

Question 35

What percent of BOR pts have HL

Answer 35

80% (50% mixed, 30% CHL, 20% SNHL)

Question 36

What is gene responsible for BOR

Answer 36

EYA1 on chrom 8q13.3

Question 37

Clinical features of Jervell and Lange-Nielsen's synd

Answer 37

Prolonged QT, syncope, sudden death, HL

Question 38

What is basic defect causing JLN

Answer 38

Abnl K+ channels

Question 39

What % of pts with NF1 have AN

Answer 39

5% and usu u/l

Question 40

What % of pts with NF2 have AN

Answer 40

95% and usu b/l

Question 41

Which type of NF is c/b cutaneous neurofirbromas

Answer 41

NF1

Question 42

Genetic mutations for NF1 and NF2

Answer 42

- NF1 gene (nerve growth factor gene) on chrom 17q11.2 | - NF2 gene (tsg) on chrom 22q12.2

Question 43

WHat is name for subtype of osteogenesis imperfecta in which progressive HL begins in early childhood

Answer 43

Van der Hoeve's synd

Question 44

Genetic mutations for osteogenesis imperfecta

Answer 44

- COLIA1 on chrom 17q | - COLIA2 on chrom 7q

Question 45

What dz is c/b cranial synostosis, exophthalmos, parrot-beak nose, and hypoplastic mandible

Answer 45

Crouzon

Question 46

What is basic defect of Crouzon's

Answer 46

Abnl fibroblast growth factor receptors

Question 47

What is Norrie synd

Answer 47

X-linked dz c/b blindness, progressive MR, and HL

Question 48

What synd is c/b hypertelorism, short stature, broad fingers and toes, CP, and CHL

Answer 48

Otopalatodigital synd

Question 49

X-linked synd a/w Klippel-Fiel synd, SNHL, CN VI paralysis

Answer 49

Wildervanck synd

Question 50

What dz is c/b lower lid colobomas, downward slanting palpebral fissures, hypoplastic mandible, malformations of external ear, CP, HL

Answer 50

Treacher-Collins (auto dom)

Question 51

Treacher collins mutation

Answer 51

TCOF1 on 5q (protein Treacle)

Question 52

“What do Keams–Sayre, MELAS, MERRF, and Leber’s hereditary optic neuropathy all have in common?

Answer 52

All mitochondrial d/o w/ varying degrees of HL

Question 53

What organism is m/c a/w virus-induced congenital deafness

Answer 53

CMV

Question 54

what percent of kids with congenital CMV have HL

Answer 54

10% are born with HL, 10-15% eventually develop HL

Question 55

What manifestation of congen syphilis is m/c related to SNHL

Answer 55

Interstitial keratitis

Question 56

3 classic findings of congen rubella synd

Answer 56

SNHL, cataracts, heart malformations

Question 57

If one parent and one sibling are deaf, what is risk of HL for subsequent offspring

Answer 57

40%

Question 58

What percent of infants w/ sig congen HL will not have RF

Answer 58

50%

Question 59

What is incidence of congen aural atresia

Answer 59

1:10,000-20,000

Question 60

What % of aural atresia is b/l

Answer 60

33%

Question 61

What does stenosis of EAC predispose to

Answer 61

canal cholesteatoma

Question 62

Which portion of ossicular chain is least likely to be malformed in pts with congenital aural atresia

Answer 62

stapes footplate

Question 63

What is incidence of FN displacement in congen aural atresia

Answer 63

25-30%

Question 64

What is a congenital cholesteatoma

Answer 64

embryonal inclusion of undifferentiated squamous epith in ME behind intact TM, usu w/ no h/o OM

Question 65

Other than middle ear, where else may congen cholesteatomas arise

Answer 65

petrous apex, CPA, mastoid, EAC

Question 66

What % of congen cholesteatoma is b/l

Answer 66

3%

Question 67

T/F: Mastoid bones of pt w/ congen cholesteatoma are most often well aerated

Answer 67

true

Question 68

What is thought to be cause of congen malleus ankylosis

Answer 68

“Poor development of the epitympanic space leaves the head of the incus and malleus in close contact with the tegmen; a bony bridge can result between the epitympanum and the head of the malleus.

Question 69

“True/False: Histologically, the bony structures are normal, without evidence of otosclerosis, in cases of malleus ankylosis.

Answer 69

true

Question 70

What is optimal tx for malleus fixation

Answer 70

removal of head of malleus and interpositionof incus b/w manubrium and stapes head

Question 71

“What genetic defect results in either Jansen’s chondrodystrophy or Blomstrand’s chondrodystrophy?

Answer 71

“Mutation of the type 1 parathyroid hormone receptor.

Question 72

What is ciliary defect in pts with Kartagener's

Answer 72

Absence of dynein side arms on A-tubules

Question 73

What is m/c site of CSF leak from inner ear into middle ear in kids

Answer 73

oval window (esp if mondini malformation)

Question 74

What are 2 types of congen defects that lead to spontaneous CSF otorrhea

Answer 74

preformed bony pathway around the bony labryinth (a/w meningitis), often a/w meningocele and aberrant arachnoid granulations located over a pneumatized area of skull

Question 75

Why does CSF otorrhea present late (50s) when caused by arachnoid granulations

Answer 75

Arachnoid granulations become larger with time; the nl pulsation of CSF pressure can cause bony erosion

Question 76

What synd is c/b recurrent episodes of vertigo and ataxia in several members of a family?

Answer 76

Familial ataxia syndrome

Question 77

“Of the four variants of this syndrome (EA1, EA2, EA3, EA4), which one does not respond to acetazolamide?

Answer 77

EA3 of periodic vestibulocerebellar ataxia

Question 78

“Which of these 4 variants is caused by mutations in a potassium channel gene (KCNA1) on 12p13?

Answer 78

EA1

Question 79

What are the 2 m/c variants of this syndrome

Answer 79

EA1 and EA2

Question 80

Which of these is a/w vertigo and results from mutations of a calcium channel gene of 19p

Answer 80

EA2

Question 81

What gene mutation is behind EA1

Answer 81

K+ channel gene KCNA1 on 12p13

Question 82

Which variant is a/w migraine

Answer 82

EA2