Treacher-Collins Syndrome (TCS) and Pierre Robin Sequence

00:01 In this lecture, we're going to review Treacher-Collins and the Pierre Robin sequence.

00:06 The idea here is to cover 2 genetic problems where they have micrognathia and difficulty with feeding and breathing early after birth.

00:14 Let's start with Treacher-Collins syndrome.

00:17 This is characterized by hypoplasia of the zygomatic bone and the mandible.

00:22 They also have external ear anomalies.

00:25 They will have a conductive hearing loss because of those external ear anomalies and you may see coloboma of the lower eyelid where it drifts down as you can see in this picture.

00:36 The incidence of disease is between 1 in 10,000 and 1 in 50,000 live births.

00:40 So, let's discuss the genetics of the disease.

00:44 It's an autosomal dominant condition.

00:46 The TCOF1 is the main gene involved.

00:50 About 40% of patients will have an affected parent and 60% will be a de novo mutation.

00:57 So, the clinical diagnosis is how this is made.

01:01 Patients will either have 2 major or a 3 minor criteria, we'll go over those in a second, and if they do, then you may suspect they have the gene.

01:10 In that case, you can send genetic testing for the TCOF mutation.

01:14 So, what are the major criteria? Major criteria are hypoplasia of the zygomatic bones and the mandible, they should have small malformed ears, microtia, and often they will have that coloboma of the eyelid and sparse or absent eyelashes.

01:33 Then there's the minor criteria.

01:36 External ear anomalies such as atresia may exist, they may have a conductive hearing loss, they should have a cleft lip with or without a cleft palate, and they may have preauricular hair displacement or hair growth in front of the ears which grows lateral to the cheekbones.

01:58 They have forward growing hair.

02:00 So, this is to be compared with the Pierre Robin sequence, which is a different problem but also presents with a very small chin or micrognathia.

02:12 These patients have a posterior displaced tongue or glossoptosis.

02:18 So, the pathology of this is different because this is a sequence rather than a syndrome.

02:26 At 9 to 11 weeks of embryonic development, they develop mandibular hypoplasia.

02:32 They thus develop a posterior displacement of the tongue.

02:36 This prevents the palatine shelves from growing together horizontally and fusing.

02:43 Thus, they often have a U-shaped cleft palate as well.

02:47 So, how do we diagnose the Pierre Robin sequence? It's a clinical diagnosis.

02:53 We expect to see that small chin and that posterior located tongue.

02:58 In about half of cases, it's associated with another syndrome.

03:02 So, we may do genetic testing to pursue the underlying syndromic cause.

03:07 How do we manage all these children? Both children with Treacher-Collins and children with Pierre Robin, they may all have difficulties with airway management, especially the upper airway, shortly after birth.

03:20 We may have to intubate them and then arrange for a more stable airway in another way, either through reconstruction or a tracheostomy or they may be able to manage it on their own.

03:31 Often, they have feeding difficulties, especially on Pierre Robin with that posterior located tongue, it can be very challenging.

03:39 Sometimes, we can find special nipple arrangements that work for them out of a bottle or occasionally we'll have to put in a G-tube and feed them that way until they can eventually develop and start eating on their own after a surgical repair.

03:53 The caveat here is feeding difficulties early in life can lead to chronic long-term feeding difficulties.

04:02 There's something about successfully completing a swallow and having the sense of satiety after going through the effort of a meal, it's really important for young babies.

04:14 And these children who don't have that opportunity, like other children who might not, for example, a child who has complex congenital heart disease, may often have difficulty with feeding later on in their life and difficulty with growth as well.

04:28 So, how do we manage their airways? First, we may reposition them and put them in a more prone position to help that narrow airway.

04:37 We may require a special feeding technique like special bottles.

04:41 We may provide them with a nasopharyngeal airway to allow for easier air exchange through the nose, and in severe cases we'll do a tracheostomy.

04:51 Sometimes, the surgeons will be needed to help us with the airway.

04:55 The surgeons may do a surgical attachment of the tongue more anteriorly in Pierre Robin.

05:01 This is reversible and is generally detached once the cleft palate is repaired.

05:06 We may do jaw distraction techniques and surgically we can lengthen gradually the jaw bone and bring out the jaw.

05:15 Then in the gaps we fill in with new bone, so we're gradually growing surgically a new jaw or an extended jaw for these patients.

05:24 Remember, with any cleft palate patient, we have to do special bottles and special nursing to teach parents how to effectively feed those children.

05:35 We have to manage any gastroesophageal reflux that occurs because they may have a harder time handling a reflux, and in severe cases, we have to do a G-tube or a gastrostomy tube to allow them to get adequate nutrition to grow until they can learn to eat later after they've been reconstructed.

05:53 So, that's my review of these 2 significant syndromes of small jawed children, Pierre Robin sequence and Treacher-Collins.

06:02 Thanks for your time.