# Case Report: A developmental and epileptic encephalopathy 45 due to de novo variant of GABRB1

## TL;DR

A new genetic variant in GABRB1 is linked to a rare neurological disorder causing developmental delays and epilepsy.

## Contribution

Identification of a de novo GABRB1 variant as a potential cause of developmental and epileptic encephalopathy 45.

## Key findings

- A heterozygous variant c.686C > T in GABRB1 was found in a child with DEE45.
- The variant was not present in either parent, suggesting it is de novo.
- The variant is proposed as a possible cause of DEE45 based on clinical and genetic analysis.

## Abstract

The gamma-aminobutyric acid (GABA) variant causes developmental and epileptic encephalopathy 45 (DEE45), an autosomal dominant disorder that results in oculocortical visual impairment, reduced muscle tone, psychomotor retardation, and epilepsy. Analysis of the clinical features and genetics of DEE45 may be helpful in complementing genotype-phenotype studies.

We collected peripheral blood samples from the affected children and parents and extracted genomic DNA. Whole exome sequencing (WES) was utilized to identify the underlying disease-causing variant. WES showed that the prior carried a heterozygous variant c.686C > T p.(Ala229Val) in exon 7 of the GABRB1 (NM_000812.4), and no variant was detected in either parental sample. The child has DEE45.

The variant c.686C > T of the GABRB1 is a possible cause of DEE45. Gene variant analysis of the relevant family lines using WES provides effective genetic counseling for developing and regressing such patients in the clinic. However, further studies are needed to verify the pathogenic mechanism.