The most prominent clinical features are:
- a combination of aplasia or hypoplasia of one or both the clavicles. This permits a wide range of shoulder movements that would not occur normally, including the ability to move the shoulders in front of the chest
- large wide open fontanelles (soft spots in a baby's head) at birth, which may remain open throughout life. The forehead is broad and flat. The head shape is described as brachcephalic, meaning that the head is disproportionately wide
- the skull base is short and the maxilla (midface or upper jaw) hypoplastic
- the eyes are wide set and prominent
- the dentition is severely affected - delayed or failure of eruption of both the primary and secondary teeth; delayed exfoliation (loss) of the primary teeth and the presence of numerous supernumerary (extra) teeth.
Other skeletal characteristics identified include:
- short, tapering fingers and short broad thumbs
- pes planus (flat feet)
- genu valgum (knock knees)
- short stature.
Conductive hearing loss due to middle ear effusions (presence of fluid in the middle ear) can occur. Recurrent sinus infections are common. A tendency for obstructive sleep apnoea (OSA) has been reported. Intelligence is normal compared to unaffected siblings.