Microtia / Atresia

When Xander was born we had never heard of Microtia or Atresia.  I remember looking at my beautiful perfect little baby wondering what this meant. Was there something I could have done differently?  What there something else wrong that we couldn’t see?  Luckily for us, there were no other health issues.


What is Microtia?

Microtia is a malformation of the outer ear.  At early stages of pregnancy, for some reason, the ear has stopped growing.  It is often accompanied by Atresia as the outer ear and ear canal are developed at the same time.  This can occur on one or both sides, in Xanders case, he has Microtia/Atresia on his left side.

There are 4 Grades of Microtia:

Grade I : a slightly small ear with identifiable structures and a small but present ear canal.  Grade I Microtia is not usually associated with deafness.

Grade II : a partial pinna (outer ear) with a closed off ear canal. Grade II Microtia causes conductive deafness.

Grade III : the pinna, ear canal and ear canal and eardrum are missing.  There may be a small peanut-shaped lobe near where the pinna would be. Grade III Microtia causes conductive deafness.

Grade IV : may be known as anotia and means ‘no ear’


Xander has Grade III Microtia.


What is Atresia?

Atresia is the absence of the ear canal.  This is what causes a conductive hearing loss.  As Xander has Atresia on his left ear, he has a unilateral hearing loss.  Please go to Xanders Hearing to read more about that.


What causes Microtia / Atresia?

Microtia very rare, it is known to affect about one baby in every 8,000 – 10,000 births worldwide.  Latest figures show that in 2011, 21 babies were born with Microtia in Australia (about 1 in 15,000 births).

Although there is constant research being done, no strong evidence has pin pointed the cause.  5% of causes are thought to be cause by Genetics.

Microtia / Atrestia is often an isolated condition, but there are a number of syndromes that Microtia /Atrestia is part of.  In Xanders case, he is part of the oculoauriculovertebral spectrum (OAVS).