Robin sequence (RS) is a developmental malformation characterised by micrognathia, cleft palate, and glossoptosis, leading to respiratory and feeding difficulties in the majority of affected neonates.^1,2 These three features constitute the primary diagnostic criteria of RS, although diagnosis on the basis of any two of these three classical features has been suggested.³ Typically the condition occurs sporadically, but it may be familial, in which case the mode of inheritance is autosomal dominant.^4,5 However, the pathogenetic and phenotypic variability of RS has hampered efforts to establish a clear set of diagnostic criteria,^3,6,7 making the classification of this anomaly difficult and complicating the effective management and treatment.^8,9 Hence, the diagnosis of RS presents a challenge from both a clinical and a developmental perspective.

RS has three different manifestations: (a) as part of a known syndrome; (b) in association with other abnormalities that do not constitute a recognisable syndrome (non-syndromic), and (c) in a classical or isolated form not associated with any other significant findings.^3,6,10 Approximately 20–40% of reported RS cases occur in an isolated form, while between 35 and 70% of cases are syndromic.^11–15 The most common syndromes associated with RS include Stickler syndrome and velocardiofacial syndrome.^15,16 While the underlying genetic factors in a number of the syndromes that include RS have been delineated,^17–19 the genetic basis for isolated RS remains unclear.

The developmental basis of RS is still contentious and it is conceivable that more than one pathogenic mechanism may be responsible for the full range of RS manifestations. One proposed theory for the origin of RS argues that mandibular hypoplasia, resulting from a developmental anomaly in either growth or placement of the mandible, is the primary defect.²⁰ The cleft palate …