One in 1,000 children present a severe or profound deafness at birth: the cause can be genetic or environmental (CMV embryopathy, for example). Deafness can secondarily appear either due to a genetic factor (progressive deafness) or an environmental factor: meningitis, labyrinthitis, acoustic trauma...

Among the genetic causes, 10% are part of a syndrome; the others are isolated or familial in the context of a monogenic disease.The severity of the hearing loss is classified on the basis of the tonal loss:

-        light: 21 to 40 dB

-        mild: 41 to 70 dB

-        severe: 71-90 dB

-        deep: 91-120 dB.

From a genetic point of view, the hearing losses are classified according to their mode of transmission: FOLKINS (autosomal recessive transmission), DFNA (autosomal dominant transmission), DFNX (X-linked transmission), DFNM (transmission by the mitochondrial genome) and DFNY (Y-linked transmission). The loci where mutations are distributed are as follows: DFNA 1 to 64. DNFB 1 to 95; DFNX 1 to 5; DFNY and 7 mitochondrial mutations. These genes code for a variety of proteins involved in hearing: proteins of the tight junctions (CDLNI4, TJP2), channels and transporters (SLC26A4, KCNQ4), enzymes, growth factors, ribosomal RNA, etc.

Typical features:

• nonsyndromic deafness: the most common are

-        DFNB1 (the cause of 60 % of nonsyndromic deafnesses) and 30 % of sporadic deafness due to a mutation in the GJB2 gene  coding for connexin 26; the predominant mutation is as common as that of cystic fibrosis; profound sensorineural deafness in 50 % of cases

-        DFNB4 (5-6 %) due to a mutation in the  SLC26A4 gene coding for pendrin: deafness of cochlear origin, that evolves in steps of sudden worsening)

-        DFNX2 due to a mutation in the POU3F4 gene: perception deafness with significant transmissional component; anomalies to the petrous bone

• syndromic deafness: deafness is included in hundreds of syndromes, such as

-        Alport syndrome: progressive deafness with  micro- and macroscopic hematuria due to a glomerulopathy. Progressive renal insufficiency.

-        branchio-oto-renal (BOR) syndrome: association of anomalies of the branchial arches (clefts, fistulas), a transmission  or sensorineural deafness, anomalies of the external ear (badly hemmed ears) and renal abnormalities (malformations, hypoplasia, agenesis, cysts).

-        Jervell-Lange-Nielsen syndrome: long QT

-        Pendred syndrome: due to a mutation in the same SLC26A4 gene as DFNB4, it combines deafness of cochlear origin that  often evolves in steps of sudden worsening, an  euthyroid goiter (2th decade of life) due to a disorder of the organification of iodine. Morphological abnormalities of the petrous bones: dilation of the aqueduct and incomplete cochlea.

-        Usher syndrome: association of deafness, disorders of the balance and retinitis pigmentosa. Indication of early implantation of bilateral cochlear implants. The subtype I is accompanied by vestibular areflexia

-        Waardenburg syndrome: association of deafness with pigmentation abnormalities (white hair, bicoloured iris, plaques of skin depigmentation). Sometimes associated with Hirchsprung's disease.

Anesthetic implications:

exclude the presence of a syndrome (clinical examination, ECG); presence of the parents for the induction and emergence of anesthesia (sign language, lip reading). Be careful with ototoxic antibiotics. The risk of anesthetic complications is mostly respiratory but is not different from the children of the same age.

References : 

• Blanchard M, Thierry B, Marlin S, Denoyelle F. 
  Aspects génétiques de la surdité. 
  Arch Pédiatr 2012 19;886-9.
• Yeh JS, Mooney KL, Gingrich K, Kim JT, Lalwani AK. 
  Anesthetic complications in pediatric patients undergoing cochlear implantation. 
  The Laryngoscope 2011; 121; 2240-4.

Updated: September 2019