The most typical features of the TRIO-related intellectual disability syndrome include:
- Feeding difficulties sometimes requiring assistance or tube feeding.
- A small head size (also referred to as “microcephaly”).
- Delay in reaching developmental milestones such as sitting up, crawling and walking. The appearance of first words or phrases or phrases is also delayed.
- Intellectual disability (possibly requiring special education).
- Behaviour problems, most often hyperactivity with concentration problems, aggression or features reminiscent of autism.
- A particular form of hands, consisting of short fingers looking more swollen at their proximal part or joints as well as a curvature of the small finger.
Other common features include:
- Dental anomalies, among others misalignment or overlapping of teeth. A few patients had delayed teeth eruption or had missing (unerupted) teeth.
- Asymmetric appearance of the face and small jaw.
- Abnormal spine curvature such as scoliosis or kyphosis.
Few patients have been reported to have respiratory problems (frequent airway infections), constipation or epilepsy.