Bryant-Li-Bhoj Neurodevelopmental Syndrome 1
Autosomal dominant
Caused by a change in one copy of H3-3A (formerly H3F3A), which makes histone H3.3, a protein that packages DNA and controls gene activity. The reported changes include missense, synonymous and stop-loss variants, and are typically de novo.
Signs and symptoms
Developmental delay and intellectual disability, typically in the severe range, with low muscle tone and delayed or absent speech. Seizures, craniofacial differences (including early fusion of skull bones), poor growth and eye involvement can occur. Less often there are brain differences on MRI, heart or genital differences, or feeding difficulties.
What a diagnosis changes
Developmental, speech and educational support, with neurological, eye and growth assessment; seizures are treated with standard medicines. The change is typically de novo, so the risk to other family members is presumed to be low, but genetic counselling is available and prenatal and preimplantation testing are possible once the variant is known in the family.
Genes analysed
Also known as
BRYLIB1
