Feeding problems in infancy are frequently reported.
The facial characteristics consist of a round or triangular face with prominent cheekbones, almond-shaped palpebral fissures which may slant upwards, synophrys, prominent ears, a high nasal bridge and bulbous nasal tip which is upturned, a smooth philtrum with a cupid-bow shaped or thin upper lip, and a low posterior hairline.
The level of developmental delay/intellectual disability is usually mild, and normal or borderline intelligence has been reported.
There are usually minor hand anomalies present such as brachydactyly and clinodactyly of the 5th fingers. About 40% of patients have a short stature below -2 SD. Scoliosis is a less frequent feature.
Congenital anomalies, such as heart defects (mainly atrial or ventricular septal defects) occur in a subset of patients. Palatal defects and velopharyngeal insufficiency occur in about 15-20%. Hearing loss is prevalent and miscellaneous. Cryptorchidism in boys is frequent. Some patients have eye abnormalities, such as strabismus.
When seizures develop, they are usually self-limiting and respond well to treatment, however, a small number of patients with early-onset, severe refractory epilepsy has been reported.
Behavioural abnormalities can include ADHD, autism spectrum disorder, aggressive behaviour, difficulties in social interaction, obsessive compulsive disorder, anxiety, or tics.