New TBL1XR1 Gene Change Linked To Developmental Delays

What was studied

This report described one child with a neurodevelopmental disorder linked to a TBL1XR1 gene variant. The researchers performed exome sequencing in the family and identified a de novo frameshift variant, meaning the gene change was new in the child.

The paper also summarized the child’s clinical features, treatment, and long-term follow-up, and it summarized treatment information from previously published TBL1XR1 cases. The child had seizures in infancy and ongoing developmental and behavioral concerns.

What they found

The researchers identified a TBL1XR1 gene variant that they classified as pathogenic under ACMG guidelines. In this child, valproic acid up to 20 mg/kg/day was reported to result in satisfactory seizure control. During follow-up, seizures were reported to have completely disappeared at 5 and 6 months of age.

Although seizures resolved during the reported follow-up, hyperactivity, attention deficit, and global developmental delay persisted. The authors said this case expanded the reported pathogenic variant spectrum and treatment experience for TBL1XR1-related neurodevelopmental disorders.

Limits of the evidence

This was mainly a single-case report, so it cannot show how most children with TBL1XR1-related conditions will do. It also cannot show whether valproic acid would have similar results in other patients.

The abstract gives limited detail about the child, the timing of symptoms, and the summary of published cases. Because of that, it is hard to compare treatments or know the longer-term outlook beyond the follow-up described.

For families and caregivers

For families, this study suggests that a TBL1XR1-related condition may include both seizures and developmental or behavioral challenges. It also suggests that seizures may improve with anti-seizure medicine in some children, while developmental needs may continue even after seizures stop.

This may matter because genetic testing can help identify a possible explanation for a child’s symptoms and support follow-up planning. Still, this report is too small to predict an individual child’s course or the best treatment plan.

What to watch next

Larger studies with longer follow-up could help clarify seizure treatment experience and developmental outcomes in more children with TBL1XR1 variants.

Terms in this summary

de novo

A new genetic change found in the child rather than inherited from a parent.

frameshift variant

A DNA change that shifts how the gene is read, often leading to a shortened protein.

exome sequencing

A genetic test that looks at the protein-coding parts of genes.

pathogenic

A term used when a genetic change is classified as disease-causing.

ACMG guidelines

Standards from a genetics expert group used to classify whether a gene change is harmful.

valproic acid

A medicine used to treat seizures.

global developmental delay

When a child is slower than expected in several areas of development.

TBL1XR1

A gene linked to neurodevelopmental disorders when certain variants are present.