Treacher Collins syndrome

Introduction

Defects in the development of the first and second pharyngeal arches and their derivatives result in abnormal formation of the craniofacial complex, consequently giving rise to facial dysostoses. The group of facial dysostoses includes Treacher Collins syndrome (TCS), for which a genetic cause can be found in the TCOF1, POLR1B, POLR1C, POLR1D genes. Other diagnoses that are categorized as facial dysostosis are Nager syndrome, Miller syndrome, and Burn–McKeown syndrome. Mutations in the TCOF1 gene are mostly found and follow an autosomal dominant mode of inheritance. Characteristic facial features in TCOF1 -based TCS involve hypoplasia of the zygomatic arches (99%), mandible (87%), conductive deafness (91%), microtia (71%), coloboma of the lower eyelid (65%) with partial to total absence of eyelashes and down-slanting palpebral fissures (100%), and cleft palate (22%) ( Fig. 29.1 ). The presenting phenotype can range from very mild to severe, even within one family, and intelligence is usually normal. The prevalence of TCS is 1 to 9 in 100,000 live births.

In this chapter, recommendations for the treatment of patients with TCS are given based on the current available literature that was graded according to the level of evidence (see Algorithm 29.1 ). Most of these recommendations are also applicable to the other types of facial dysostosis.

Algorithm 29.1

Recommended care pathway for Treacher Collins syndrome based on the current available literature.

Systemic literature review of current treatments

As a sequel to the systematic review by Plomp et al ., a similar literature search was undertaken in Embase, PubMed, Web of Science, and Cochrane from January 2014 to January 2020. The search term was “Treacher Collins”. Excluded were proceedings, book chapters, case reports, no abstract available, inaccessibility of the full text, and studies not related to clinical practice.

Included were English-language clinical studies related to therapy, diagnosis, or risk of concomitant diseases, that included at least five TCS patients. Seven functional topics were investigated: upper airway; the ear, hearing, and speech; the eye and lacrimal system; growth, feeding, and swallowing; the nose; psychosocial factors; and craniofacial reconstruction. All the studies were included per topic of interest and a level of evidence was assigned. Level of evidence was based on the American Society of Plastic Surgeons Evidence-Based Clinical Practice Guidelines .

Of the original systematic review by Plomp et al ., only the papers that were graded level I, II, or III and were published in 2000 or later were incorporated in this chapter. If a paper had a sequel from the same institute with a longer follow-up, the first paper was disregarded.

The number of eligible papers in the four databases were 293 in EMBASE, 118 in PubMed, 100 in Web of Science, and none in Cochrane. After applying the selection criteria and removing double citations, 18 papers published between 2014 and 2021 were left. The level of evidence per paper is provided in Table 29.1 . A total of 17 papers in the systematic review by Plomp et al . were selected as described, summing up to 35 papers that are included in this chapter, and contributed to the recommended algorithm in Algorithm 29.1 .