[MIM 610 706]

Acronym for Labyrinthine Aplasia, Microtia and Microdontia.

Extremely rare. Syndromic genetic deafness. Autosomal recessive transmission of a mutation of the FGF3 gene (fibroblast growth factor 3)(11q13.3.)

Association of :

-        complete aplasia of the labyrinth, also known as Michel's aplasia, resulting in profound deafness ;

-        type I microtia (usually bilateral): small pinna and narrow external auditory canal

-        microdontia with widely spaced teeth.

Aplasia of the labyrinth is one of the cochleovestibular dysplasias (Sennaroglu classification):

1.        complete aplasia of the labyrinth: Michel's” aplasia

2.        cochlear aplasia

3.        common cavity

4.        incomplete partition of the cochlea, 3 types:

1.        absence of modiolus and septa: the cochlea appears as a coarse cystic formation. Usually dilated vestibule.

2.        Mondini malformation or dysplasia (see this term): normal basal turn of the cochlea, hypoplasia of the modiolus with fusion of the second turn and the cochlear apex. Dilatation of the vestibular aqueduct.

3.        cochlear malformation in X-linked deafness. Modiolus absent but septa present. The cochlea directly connected with Internal Auditory CAnal.

5. cochlear hypoplasia, 3 types:

1.        “cochlear bud” without modiolus or septa. Resembles malformation 4(1) but the cochlea is “small”.

2.        cystic cochlea without modiolus or septa, but with preserved external architecture. Wide communication with the internal auditory canal (geyser ear or Gusher syndrome, see congenital deafness).

3.        micro-cochlea, < 2 turns.

6.        LVAS or “Large Vestibule Aqueduct Syndrome”: dilatation of the vestibule aqueduct.

7.        Narrow internal auditory meatus.

Anesthetic implications:

deafness; fragile teeth. Since cochlear implants are of little or no benefit in this condition, brainstem auditory implants can be tried in very young children. This is a delicate neurosurgical procedure, involving :

-        intraoperative monitoring of cranial nerves VII, VIII, IX, XI and XII (skin electrodes, intraoral electrodes and electrodes around the endotracheal tube in the larynx) and brainstem responses to stimulation

-        no curarization

-        total IV anesthesia with propofol to avoid the effects of halogenated agents on evoked potentials.

-        lumbar drainage of CSF

References : 

-        Sensi A, Ceruti S, Trevisi P, Gualandi F, Busi M, Donati I, Neri M, Ferlini A, Martini A. 2011. 
LAMM syndrome with middle ear dysplasia associated with compound heterozygosity for FGF3 mutations. 
Am J Med Genet Part A 2011; 155:1096–1101.

-        Singh A, Tekin M, Falcone M, Kapoor S. 
Delayed presentation of rickets in a child with Labyritnhine Aplasia, Microtia and Microdontia (LAMM) syndrome. 
Indian Pediatr 2014; 51: 919-20.  

-        Gungor G, Bozkurt PS, Yener HM, Yilmaz YZ, Atas A, Yilat S, Hayir D.
Comparison of anesthetic agents on otoacoustic emission in children : propofol vs ketamine. 
Pediatr Anesth 2016 ; 26 :752-8.

-        Reddy A, Panda N, Ghai B, Panda NK, Kameswaran M, Vasudevan MC.
Overcoming anesthetic challenges in a child with Michel's aplasia undergoing auditory brainstem implantation.
Pediatr Anesth 2024 ; in press

Updated: July 2024