Hereditary Hearing Loss

Posted by e-Medical PPT Tuesday, June 5, 2012
Crouzon Syndrome
DEFINITION –Hearing Loss present at birth or develops any time thereafter and is believed to have a genetic cause.
“Congenital” which is a general term for Hearing Loss present at birth
Acquired Prenatal Hearing Loss (Syphilis, Rubella, CMV, Toxic Exposure)
Other HL (congenital cholesteatoma, otosclerosis, sudden SNHL)

Associated Anomalies

Developmental Onset

Genetic Classification
Autosomal Dominant
Autosomal Recessive

AD Syndromic
Branchio-Oto-Renal – Outer/Middle/Inner Ear Anomalies (preauricular pits common, microtia, etc), Lateral cervical sinus/cyst/cleft, Renal agenesis/dysplasia, HL (90%) is SN/C or Mixed prelingual
NF-II – Bilat Schwannomas, meningiomas, gliomas, cataracts/lenticular opacities, HL is retrocochlear and usually postlingual - MERLIN gene
Stickler – congenital vitreous anomaly AND any 3 of: myopia before age 6, retinal detachment/lattice degen, joint hypermobility, SNHL, midline cleft (may be sumucous). May have Robin Seq, HL may be mixed pre/post lingual, 50% blind by adolescence, marfanoid habitus

AD Syndromic (cont’d)
Waardenburg – Four types: Type I = SNHL, White Forelock, heterochromia/hopoplastic blue eyes, dystopia canthorum. Can also have synophrys, broad nasal root, alar hypoplasia.  Type 2 = no dystopia canthorum. Type 3 = Type 1 + upper limb contracture. Type 4 = incld Hirschprung.  For all types, HL is prelingual.
Treacher Collins – 1st branchial arch abnormalities of midface hypoplasia, micrognathia, macrostomia, colobomas of lower lids, downward palpebral fissures, Cleft Palate, CHL (EE/ME anomalies).
Crouzon – craniosynostosis, hypertelorism, midface hypoplasia, exophthalmos.  1/3 CHL due to EE/ME anomalies.

AR Syndromic
Jervell Lange-Nielsen – Profound prelingual SNHL, syncope, sudden death (prolonged QT). Syncope w/ exertion or emotion. High mortality rate sig reduced w/ Dx and Tx.
Pendred – Prelingual (usu profound) SNHL and Goiter. T-bone abnormalities (Mondini, DVA).  Goiter may develop later in childhood but usually euthyroid.
Usher – Most common AR syndromic HL, has prelingual SNHL plus retinitis pigmentosa.  ½ of all Deaf-Blinds in US.  3 Types: USH1 – includes vestibular areflexia (no caloric response) and profound HL, USH2 – nl vestibular fct and use HA, USH3 – progressive HL and vestibular probs.  In all 3, RP is progressive, starting w/ nyctaltopia (night blindness).  Electroretinography (ERG) for early RP dx.

X-Linked Syndromic
Alport – SNHL (hi freq), progressive glomerulonephritis, anterior lenticonus, white macular flecks (or both). Screen hematuria/proteinuria (multiple specimens) usually found age 3-4 yrs, esp after URI.

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