All individuals with TBRS experience some degree of developmental delay and/or intellectual disability, with 86% of well-documented cases falling in the mild to moderate range.
Most individuals with TBRS exhibit increased stature, head circumference, and weight at least two standard deviations above the mean.
Approximately half of individuals exhibit behavioral or psychiatric issues; the most common diagnosis is autism spectrum disorder.
[1] The facial gestalt of TBRS includes a round face; thick, horizontal, low-set eyebrows; vertically narrow palpebral fissures; and prominent maxillary central incisors.
[1] Neuroimaging findings may include corpus callosum anomalies, small posterior cranial fossa, asymmetric arcuate and uncinate fasciculi, deep left Sylvian fissure, and increased cortical thickness[4] TBRS is caused by autosomal dominant mutations in the DNMT3A gene.