TITLE: Pediatr=
ic
Syndromic Hearing Loss
SOURCE: Grand Rounds Presentation, UTMB, Dept. of Otolaryngology
DATE: September 24, 2009
RESIDENT PHYSICIAN: Ryan Ridley, MD
FACULTY PHYSICIAN: Shraddha Mukerji, MD
DISCUSSANT: Shraddha Mukerji, MD
SERIES EDITORS: Francis B. Quinn, Jr., MD
ARCHIVIST: Melinda Stoner Qui=
nn, MS(
"This material was prepared by resident physicians in partial fulfillment of educational requirements established for the Postgraduate Training Program of the UTMB Department of Otolaryngology/Head and Neck Surgery and was not intended for clinical use in its present form. It was prepared for the purpose of stimulating group discussion in a conference setting. No warranties, either express or implie= d, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion."
Introduction
An estimated 1 in 1,=
000 of
the US population is born deaf or displays profound hearing loss early in c=
hildhood
(Cotton and Myer). Of these, =
half
are acquired prenatally while the remaining half will exhibit hearing loss =
as a
result of hereditary-genetic factors. Approxim=
ately one-third of children with
genetic hearing loss will display phenotypic characteristics of a syndrome
while two-thirds will be nonsyndromic (i.e. hearing loss in the absence of
other features). Whether the hearing loss is syndromic or nonsyndromic, it is of the utmost
importance to identify these patients early so that the proper auditory reh=
abilitation
and corrective measures can be implemented in time to provide the best
prognosis. The discussion bel=
ow
will focus on syndromic forms of hearing loss as there are a plethora of
syndromes that manifest an auditory phenotype.
Embryology of the Ear
Most deformities that
present congenitally are often the result of some insult that occurs during=
the
gestational development of the fetus.
Knowledge of the embryology of the ear will serve as a good foundati=
on
with which to understand some of the syndromic malformations that display e=
ar
abnormalities and hearing loss.
Mesenchymal tissue from the first and second branchial arches contain
the Hillocks of His which organize to form the auricle at 4 weeks
gestation. The auricle is
completely formed by 12 weeks with deformities and/or absence traceable as
early as 7-8 weeks. Generally
speaking, the earlier the insult in the developmental
The external auditor=
y canal
(EAC) begins forming at 8 weeks when the ectoderm from the first branchial
cleft joins the developing tympanic ring.&=
nbsp;
The tympanic ring begins ossification at 12 weeks giving way to the =
bony
EAC. At 28 weeks, the EAC beg=
ins to
canalize producing a three layered tympanic membrane, thus abnormalities of=
the
EAC are usually in conjunction with tympanic membrane abnormalities. Atresia occurs as a result of fail=
ure of
the EAC to canalize and stenosis as a failure of complete canalization. Both atresia and stenosis can be t=
raced
to approximately 28-30 weeks gestation.&nb=
sp;
The formation of the=
stapes
initializes ossicular development at 4 ½ weeks. The footplate begins to form at 7-9
weeks an d uninterrupted development is crucial =
to
avoid malformations or absence of the oval window. At 12 weeks the anterior and poste=
rior
crura of the stapes become bowed and their ossification takes place between
18-24 weeks. Deformitie=
s of
the stapes footplate and/or superstructure can be linked to the 12 week poi=
nt
on the embryonic timeline. The development of the malleus and incus begins =
at 5
weeks from Meckel’s cartilage of the 1st arch and
Reichert’s cartilage of the second arch. A fused malleus-incus mass o=
ccurs
when the middle ear mucosa fails to develop and separate the undeveloped
ossicles from the tympanic cavity.
The incus is the first ossicle to ossify at 15 weeks followed by the
malleus at 16 weeks and is complete by 24 weeks.
The inner ear exists=
as the
otic vesicle embryonically which appears approximately week 4. The otic vesicle then splits into =
a pars
inferior and a pars superior (week 5) which will be the precursors of the
semicircular canals (SCC) and utricle (pars inferior) as well as the cochlea
and saccule (pars superior). &n=
bsp;
Differentiation of the pars inferior and superior into the SCC, utri=
cle,
cochlea and saccule occur in weeks 6-7.&nb=
sp;
The cochlea develops its basal turn, 1.5 turns and complete 2.5 turn=
s by
weeks 7, 8 and 10 respectively. Interruptions
at this point are responsible for malformations such as Mondini’s
dysplasia. During the same ti=
me period
as the division of the otic vesicle into the pars superior and inferior, the
acousticofacial ganglion divides into the acoustic ganglion and the facial
ganglion. At week 5, the acou=
stic
ganglion separates into a superior and inferior division with the superior
division innervating the neuroepithelium of the superior portion of the otic
vesicle (utricle, superior and lateral SCC). The inferior division of the acous=
tic
ganglion will innervate the neuroepithelium of the saccule and the posterior
SCC. Meanwhile, the facial ga=
nglion
will innervate the structures of the second branchial arch.
Basic genetics and defin=
itions
In continuity with
establishing a foundation for understanding the pathology of syndromes, a b=
rief
discussion of inheritance patterns as well as definitions to some frequently
used terminology will be addressed.
Hereditary Patterns
Autosomal Domi=
nant: Disorders with this mode of inherit=
ance
are usually expressed with alteration of only one gene in a gene pair. Males and females are equally affe=
cted
and male-to-male transmission occurs.
There is a 50% risk of an affected parents
offspring being affected (male or female).=
Several factors may influence the clinical presentation such as
decreased penetrance, variation in expressivity and age of onset.
Autosomal Rece=
ssive: Nearly one-third of mendelian
disorders share this hereditary pattern.&n=
bsp;
This pattern occurs when both parents are unaffected carriers. Each parent transmits either the n=
ormal
or mutant gene to each of their offspring.=
As a result, there is a 25% risk of the children being affected. The risk of having siblings who are
unaffected carriers is two-thirds.
Consanguinity and reproduction among genetically isolated groups
increases the risk of autosomal recessive disorders.
X-linked inher=
itance: X-linked recessive disorders are a=
lways
expressed in males because they only have one copy of the X chromosome. In contrast, females are usually
carriers since they possess two copies of the X chromosome. Females become carriers as a resul=
t of
transmission from their affected fathers.&=
nbsp;
Since males only receive Y chromosomes from their fathers, father-
Mitochondrial
Inheritance: All
mitochondrial genes, located in the ovum at the time of conception, are
inherited from the mother because sperm cells do not contribute
mitochondria. conditions
caused by mutations in the mitochondrial genome are described as following
maternal inheritance and affect both male and female offspring.
Definition of commonly used terminology
Penetrance: This refers to the modification of
traits by other genes and/or environmental factors they may render them
clinically absent although the gene responsible for the trait is present.
Expressivity: The variation in expression of a
gene’s phenotype. The g=
ene is
present, but may express the phenotype in a mild, moderate or severe form w=
hich
will correlate with disease severity.
Pleiotropy: The mu=
ltiple
phenotypic effects in an affected individual as a result of the mutant gene=
or
gene pair.
Malformation: Results when an abnormal developme=
ntal
process is responsible for amorphologic defect in an organ, part of an orga=
n or
a region of the body.
Syndrome: The simultaneous presence of two o=
r more
malformations that are proven or assumed to be secondary to a single etiolo=
gy.
Deformation: Occur =
due to
extrinsic mechanical forces; not related to genetic information. An example
would be plagiocephaly.
Disruption: This h=
appens
when processes such as ischemia, tissue breakdown, etc victimize a normal
developmental process. Amputa=
tion
of normally formed digits or limbs by free-floating amniotic bands as a res=
ult
of early amnion rupture would be an example.
Sequence: A patt=
ern of
multiple defects that result from a single primary malformation. An example is Pierre Robin sequenc=
e in
which micrognathia results in tongue displacement which results in cleft
palate.
Association: A pattern of anomalies that occur = in conjunction with one another more frequently than expected but have yet to = be identified as a distinct syndrome or sequence. CHARGE association is an example (coloboma, heart anomalies, choanal atresia, retardation, genital andear anomalies).<= o:p>
Practical approach to the
syndromal child child with hearing loss
As stated earlier, g=
enetic
hearing loss can either be syndromic or nonsyndromic. Physical exam and lab
tests/investigations aim to detect those with syndromic hearing loss which
account for 30% of genetically caused hearing loss. It is vital to identify cases that=
have
an obvious genetic etiology in order to make a diagnosis and begin early and
aggressive hearing rehabilitation as this affects prognosis in terms of spe=
ech
and language development.
When taking an initi=
al
history for a pediatric patient with hearing loss, the physician should
entertain the possibility of a genetic cause. When taking the family history, the
physician should specifically inquire regarding the hearing status of the
parents. Although the parents=
may
appear to have no hearing deficits, the physician must bear in mind that on=
e or
both of the parents may be exhibiting variable expression of a mutant gene =
or
reduced penetrance. This could
especially be true of normal hearing parents who report having parents with
early onset of hearing loss.
Alternatively, the case may involve X-linked inheritance in which no=
ne
of the parents themselves exhibit hearing loss despite a positive history in
other family members. Often, =
this
information is not volunteered and must be sought by the astute clinician.<=
span
style=3D'mso-spacerun:yes'>
The pregnancy and bi=
rth
history are also important inquiries to make; especially the rubella status=
of
the mother. In addition, atte=
ntion
should be paid to the developmental history of the patient. Isolated motor delay or global
developmental delay could be clues to vestibular dysfunction or a syndrome
diagnosis respectively. Also,
reports of visual problems manifesting in the child could also point the
physician toward a syndrome diagnosis.&nbs=
p;
A thorough physical =
exam is
an important adjunct to the history and must not be confined only to the he=
ad
and neck. Checking for birth =
marks
on the trunk and limbs as well as limb deformities can prove helpful in try=
ing
to arrive at a syndrome diagnosis.
It may be helpful to ask the parents to bring old photo albums of
themselves and family members to help delineate normal familial traits from
those that may be syndromic. =
Lastly, one the hist=
ory and
physical exam are complete, there are certain lab tests and investigations =
that
may prove useful. Eudiometry =
of
first degree relatives in addition to the patient, ophthalmology evaluation,
serology for congenital infections (TORCHs), urinalysis (Export’s
syndrome), EKG (Terrell and Lange-Nielsen syndrome), chromosome analysis an=
d CT
scans for profound or progressive hearing loss.
Syndromic Hearing Loss
Autosomal Dominant Syndro=
mes
Waardenburg sy=
ndrome: Characterized by sensorineural hear=
ing
loss, abnormal pigmentation of the skin and hair, dystopia canthorum (eye i=
nner
canthi are displaced laterally), heterochromia iridis (iris colors do not
match), and pinched nose. This
syndrome occurs anywhere from 1 in 20,000 to 1 in 40,000 and accounts for 1=
-2%
of people with profound hearing loss.
The hearing loss can be unilateral or bilateral of varying
severity. The syndrome has 4 =
subtypes
classified according to the presence or absence of other abnormalities. In Type 1, every patient exhibits =
dystopia
canthorum. The Type 2 phenoty=
pe is
void of dystopia canthorum while Type 3 exists with upper extremity
abnormalities in conjunction with Type 1 characteristics. Type 4 exhibits pigmentation
abnormalities, Hirschsprung’s disease, plus findings shown in Type
2. Types 1 and 3 are linked t=
o gene
mutations in the PAX3 gene, while Types 2 and 4 are linked to the MITF and
EDNRB genes respectively.
Branchio-oto-r=
enal
syndrome: This syndrome is estimated to be p=
resent
in 2% of profoundly deaf children. <=
/span> The syndrome displays high penetran=
ce
although variable expressivity has been shown in families. Hearing impairment is estimated to=
be
present in 70-93% of affected people but the age of onset ranges from early
childhood to young =
adulthood. Likewise, there is varied severity
ranging from mild to profound and the nature can be conductive, sensorineur=
al
or mixed. Common
characteristics of the BOR phenotype include cup-shaped pinnae, preauricular
pits, branchial cleft fistulae and bilateral renal anomalies. Other features displayed are
preauricular tags, lacrimal duct stenosis, deep overbite and a long, narrow
face. Inner ear anomalies like
Mondini’s dysplasia and stapes fixation can also be present. The gene=
tic
etiology of this syndrome can be traced to the EYA1 gene. Based on the phenotypic anomalies,
criteria have been developed for EYA1 testing: affected individuals must have at =
least
3 major criteria; two major criteria and at least two minor criteria; or one
major criterion with one first- degree family member meeting BOR criteria (=
see
accompanied POWERPOINT SLIDE SHOW presentation for table of criteria).
Stickler Syndr=
ome
(STL): In addition to having sensorineural
hearing loss that is progressive, these patients
usually display a cleft palate, abnormal development of the epiphysis,
vertebral abnormalities and osteoarthritis. There are three clinical subtypes =
that
exist. Type 1 develops progre=
ssive
myopathy, retinal detachment and vitreoretinal degeneration. Retina detachment is nonexistent i=
n type
2 due to lack of the COL11A2 gene in the retina. In Type 3 shares eye
and ear findings present in type 1 but has facial abnormalities.
Treacher Colli=
ns (TC): Also known as Fraceschetti-Zwahlen=
-Klein
Syndrome =
or
Mandibulo-Facial Dysostosis, this autosomal dominant entity is liked to
mutations on chromosome 5q11 and some reports mention an association of
maternal vitamin A hypersensitivity.
Diagnostic criteria include microti=
a and
malformed ears, midface hypoplasia, downslanting palpebral fissures, colobo=
ma
of outer 1/3 of lower eyelids, and micrognathia. The upper airway narrowing=
can
be a major issue in infancy. =
The size
of the nasopharynx is 50% smaller than normal and affected infants are more
prone to OSA and SIDS. Hearin=
g loss
in this syndrome is usually conductive with a wide array of middle ear
anomalies present such as monopodal stapes, ankylosed foot plate, malformed
incus, cochlea and vestibule abnormalities. The EAC may be absent or stenosed.=
If sensorineural hearing loss is
present, it usually occurs at high frequencies.
Osteogenesis
imperfecta (OI): This is an autosomal dominant diso=
rder
displaying the triad of bone fragility, blue sclerae and hearing
impairment. Other characteris=
tics
include triangular face, short stature, hypermobile mobile joints,
cardiovascular abnormalities and skin disorders. The incidence is estimated to be 1=
in
20,000 to 1 in 30,000. Causative mutations involve the COL1A1 or COL1A2 gene
which regulate formation of type I collagen. Hearing loss is usually mixe=
d and
has a prevalence ranging from 26-78%.
The hearing loss usually presents itself during the late 20s or early
30s. The conductive component=
of
the hearing loss is attributed to the thickened and fixed stapes footplate,
similar to what is seen in otosclerosis.&n=
bsp;
The sensorineural component usually results from cochlear hair cell
atrophy and atrophy of the stria vascularis. Also, anomalous bone formation in =
and
around the cochlea may contribute to the sensorineural component of the hea=
ring
loss.
Neurofibromato=
sis Type
II (NF 2): Bilateral vestibular schwannomas a=
re the
hallmark of this disease with a prevalence of 1 in 210,000 people. Other features include meningiomas
(intracranial and spinal), ependymomas, gliomas, presenile lens opacities, =
and
schwannomas located in the cranial, spinal and peripheral nerves. The skin can also manifest
café-au-lait spots but not to the extent found in neurofibromatosis =
type
I. This
disease is caused by an NF 2 tumor-suppressor gene mutation on chromosome
22. Affected patients usually
present in the 2nd and 4th decade. Up to 41% present =
with
unilateral sensorineural hearing loss rather than bilateral sensorineural
hearing loss due to the fact that this percentage of patients do not present
with bilateral vestibular schwannomas.&nbs=
p;
Patients can also have tinnitus, disequilibrium, headache and cranial
nerve symptoms. Children <=
15
years old may commonly present with skin or spinal tumors prior to the onse=
t of
hearing loss or development of vestibular schwannomas. In addition to the
Manchester criteria for diagnosis (see accompanied power point presentation)
patients who are suspicious for having NF 2 should undergo audiometry and M=
RI
with gadolinium enhancement of the internal auditory canals.
Autosomal Recessive Syndr=
omes
Usher Syndrome=
: Usher syndrome is the most common =
cause
of autosomal recessive hearing loss.
The incidence of Usher syndrome is approximately 3-5 per 100,000 in =
the
general population and 1-10% among profoundly deaf children. The syndrome has several subtypes =
based
on severity of the deafness and the onset of retinitis pigmentosa (gradual
retinal degeneration leading to decreased night vision, loss of peripheral
vision, and blindness). Type =
1 has
severe hearing loss and vestibular dysfunction. The onset of retinitis pigmentosa =
is in
childhood as opposed to type 2 where it begins after childhood. Mild to moderate hearing g lo=
ss
characterizes type 2 along with normal vestibular function. In type 3, hearing loss is progres=
sive
as is the vestibular dysfunction.
Retinitis pigmentosa can occur anytime in life.
Pendred syndro=
me: Characterized by hearing impairment
associated with abnormal iodine metabolism. The responsible gene is SLC26A4
(PDS). This encodes a protein=
named
pendrin which helps regulate iodine and chloride ion transport. Most patients have a euthyroid goi=
ter
which is sometimes detected at birth but often is not clinically evident un=
til
8 years of age. Diagnosis of =
the
thyroid abnormality used to depend on perchlorate discharge tests (indicates abnormal
organification of nonorganic iodine) but this test is not specific for Pend=
red
syndrome and the sensitivity is unknown.&n=
bsp;
Instead, thyroid function tests are used. The hearing loss in this syndrome =
is
severe and can be present at birth or progress with age. In addition, CT scans have revealed
cochlear dysplasia (Mondini’s) an enlarged vestibular aqueduct or
both.
Jervell and
Lange-Nielsen Syndrome:
Biotinidase De=
ficiency: Infants with severe biotinidase
deficiency will display skin rashes, seizures, hair loss, hypotonia, emesis=
and
acidosis in the first few months of life.&=
nbsp;
This syndrome occurs because the infant lacks the enzyme responsible=
for
proper biotin metabolism. App=
roximately
75% of affected infants will develop hearing loss if left untreated. The significance of this disorder =
is
that if it is recognized, all the sequelae can be avoided with biotin
supplementation.
X-Linked syndromes
Alport syndrome: As a result of the mutation in type IV collagen gene COL4A5, patients with Alp= ort = syndrome exhibit renal disorders and ocular abnormalities in addition to progressive sensorineural hearing loss. R= enal disorders include glomerulonephritis, hematuria (“red diaper”),= and renal failure. Early diagnosi= s is essential because the renal disease is usually more severe in males causing death secondary to uremia prior to 30 year old. Congenital cataracts are also comm<= /span>on. The progressive sensorineural hear= ing loss mentioned earlier usually has an onset beginning in the 2nd decade of life.
Non-genetic Syndromes
Down’s s=
yndrome: This i=
s the
most common of the chromosome abnormality syndromes typified by a wide rang=
e of
abnormalities. Otolaryngologic
findings are numerous in these patients and can affect every region of the =
head
and neck. This includes small=
ears
with overfolding of the superior helix, stenotic EAC and eustachian tube
dysfunction. There is also an
increased incidence of chronic ear disease in affected children due to
increased incidence of upper respiratory infections, reduction of B and T c=
ell
function (immune system immaturity), and eustachian tube dysfunction. The hearing loss in DS is usually
conductive secondary to the chronic middle ear disease but can also be due =
to
ossicular chain abnormalities, especially the stapes. Upper airway obstruction and OSA a=
re
also problems encountered by children with DS due to the midface hypoplasia,
and relative enlargement of the tongue, tonsils and adenoids in a constrict=
ed
naso/oropharynx. Other systems
affected include cardiovascular (ventricular-septal defect, tetrology of
Fallot, patent ductus arteriosis), genitourinary (micropenis, low testoster=
one,
infertility), musculoskeletal (atlanto-axial instability, short metacarpals=
and
phalanges) and ocular (speckled iris; Brushfield spots). In terms of speech and behavior, m=
ost
Down’s syndrome patients exhibit dysarthria and articulation deficits=
in
conjunction with some degree of mental retardation (IQ 30-50).
Fetal Alcohol =
Syndrome
(FAS): Of children born to alcoholic moth=
ers,
30-40% suffer this syndrome. The amount of alcohol intake requi=
red to
cause FAS has not been clearly established. Alcohol and its major metabolit=
e,
acetaldehyde, may be teratogenic.
The alcohol induced developmental abnormalities can be the result of
restriction of cell growth during critical periods. Characteristics of the syndrome in=
clude
prenatal and postnatal growth deficiency, microcephaly, and mental retardat=
ion
(average IQ of 63). Behavior =
is
also affected as irritability and hyperactivity are common. Neural tube def=
ects
and seizure disorder may also be present. From an ophthalmology perspective,
this syndrome causes hypoplasia of the optic nerve, increased tortuosity of=
the
retinal vessels, severe microophthalmia and colobomas. Almost no system is guaranteed to =
be
spared as cardiac, renal and skeletal anomalies may manifest themselves as =
well
as malignant neoplasms of embryonal origin. Common facial dysmorphisms include
narrow forehead, short palpebral fissures, ptosis of
eyelids, midface hypoplasia, short nose, smooth philthrum, thin upper lip a=
nd
hypoplastic mandible. In addi=
tion,
cleft palate or cleft lip may exist.
Ten percent of patients have hearing loss that may be either conduct=
ive
or sensorineural.
Goldenhar̵=
7;s
Syndrome: Also r=
eferred
to as facioauriculovertebral dysplasia (FAVD) and hemifacial microsomia (HF=
M),
this disorder results from aberrant development of the first and second
branchial arches. HFM is esti=
mated
to occur in 1 in 5600 live births, perhaps making it the most significant
asymmetric craniofacial disorder. Otologic
manifestations include microtia/anotia, preauricular tags, ossicular
abnormalities, abnormal facial nerve course, and hearing loss (conductive &=
gt;
sensorineural). The hearing l=
oss is
predominantly conductive secondary to the abnormal development of the struc=
tures
derived from the first and second branchial arches. Facial abnormalities include unila=
teral
hypoplasia of the maxilla, malar and temporal bones in addition to mandibul=
ar
ramus and condyle hypoplasia.
Macrostomia or pseudomacrostomia (lateral cleft-like extension of the
oral commisures), cleft lip or palate and delayed dental development. Lastly, the mastoid is poorly
pneumatized and their may exist agenesis of the parotid gland or displaceme=
nt
of the gland. In terms of non-head and neck featu=
res,
affected individuals can also have cardiac abnormalities such as coarctatio=
n of
the aorta, ventricular septal defect, tetrology of Fallot, and patent ductus
arteriosis. Renal ectopia and
hydronephrosis can encompass the renal abnormalities. Limb deformities can be present as=
well
as cerebral malformation and mental retardation. Ocular abnormalities include
blepharoptosis, microopthalmia, epibulbar tumors, and retinal abnormalities
leading to reduced visual acuity.
Rubella=
: Consists of a triad characterized =
by
deafness, congenital cataracts and heart defects. This disease is caused by an RNA
togavirus and is transmitted postnatally via respiratory secretion, saliva,=
or
direct contact. Transplacental
transmission is the route responsible for congenital infection which can
involve more sequelae if infection is present during the first trimester.
Cytomegaloviru=
s (CMV): CMV ha=
s an
incidence of 0.2%-2.3% of live births making it one of the most frequently
occurring viruses worldwide and the leading cause of congenital malformatio=
ns
and mental retardation in developed countries. Of all the TORCH infections,=
CMV
is the most common. Microceph=
aly,
intrauterine growth restriction (IUGR), petechiae, encephalitis,
hepatosplenomegaly, and deafness are some of the physical characteristics o=
f a
congenital CMV infection. CMV=
is
estimated to account for 1/3 of sensorineural hearing loss in young childre=
n.
Hearing impairment in CMV can be delayed (occurring months-years after birt=
h),
or fluctuating and progressive. Interesting to note, infants with petechiae=
and
IUGR are 2-3 times more likely to have sensorineural hearing loss. Post mortem temporal bone studies =
on
infants who died from cytomegalic inclusion disease have revealed inclusion
bodies in the stria vascularis, Reissner’s membrane, saccule, utricle=
and
semicircular canals. Endolymp=
hatic
hydrops was noted in the cochlear ducts.&n=
bsp;
Overall treatment goals =
in
patients with syndromic hearing loss
The important fact to remember pertaining to syndromic hearing loss is that treatment of the hearing impairment is no different than tr= eating a nonsyndromic patient with hearing loss.&= nbsp; In other words, there isn’t a special hearing treatment for the profound sensorineural hearing loss in Usher syndrome vs. the child who is profoundly deaf at birth without a syndrome. There have been studies documenting success in use of cochlear implants in syndromes manifesting sensorineural hearing loss such as Usher, Waardenburg, and Jervell and Lange-Nielsen synd= rome. Likewise, when syndromic patients = have conductive hearing loss or a significant conductive component contributing = to mixed hearing loss, the appropriate surgical procedures should be performed. This can range from being as simple as a BM&T for the recurrent middle ear effusions in Down’s to performing a stapedotomy/ossiculoplasty in osteogenesis imperfecta. Basically, the me= thod of treatment should be selected to meet the individual needs of the patient= to achieve the most benefit. In = the end, the main purpose of arriving at a syndromic diagnosis is to identify <= /span>those that will have hearing loss so that early and aggressive hearing rehabilita= tion can be initialized.
Discus=
sion by
Shraddha Mikerji, MD
Hearing loss associated with well-known syndrom=
es is
less common as compared to other non-syndromic =
causes
of congenital hearing loss.
However, when hearing loss is a feature of a ce=
rtain
syndrome, babies
and children tend to be evaluated early on for any hearing problems. Though=
the
ultimate treatment of syndromic hearing loss do=
es not
differ from that of non-syndromic hearing loss,=
early
identification of these children means early treatment and early rehabilita=
tion
with possible better outcomes.
Osteogenesis imperfect may present with condu=
ctive
hearing loss which may be clinically indistinguishable from otosclerosis.
However, other clinical features will correctly identify the children as ha=
ve osteogenesis imperfect. Though the audiological
pattern is similar for the two conditions, surgery is more complicated with
less chances of post-operative improvement in hearing in children with osteogenesis imperfect. This is related to increased =
vascularity over the stapes foot plate. Also, even if=
the
foot plate is thick it is more brittle, so can lead to floating foot plate =
and
other complications including sensorineural hea=
ring
loss.
Church MW= , Kaltenbach JA.Alcohol Clin Exp Res. 1997 May;21(3):495-512. R= eview
Hearing, language, speech, vestib= ular, and dentofacial disorders in fetal alcohol synd= rome. Church MW, Eldis F, Blakley BW, Bawle EV.Alcohol Clin Exp Res. 1997 Apr;21(2):227-37
Scholtz AW, Fish JH 3rd, Kammen<=
/span>-Jolly
K, Ichiki H, Hussl =
B, Kreczy A, Schrott-Fischer=
A.
Otol Neurotol.
2001 Jul;22(4):501-5
An overview of hereditary hearing= loss. Bayazit YA, Yilmaz = M.ORL J Otorhinolaryngol Relat Sp= ec. 2006;68(2):57-63. Epub 2006 Jan 20. Review.
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