Bi-allelic ADARB1 Variants Associated with Microcephaly, Intellectual Disability, and Seizures.
Am J Hum Genet
; 106(4): 467-483, 2020 04 02.
Article
in En
| MEDLINE
| ID: mdl-32220291
ABSTRACT
The RNA editing enzyme ADAR2 is essential for the recoding of brain transcripts. Impaired ADAR2 editing leads to early-onset epilepsy and premature death in a mouse model. Here, we report bi-allelic variants in ADARB1, the gene encoding ADAR2, in four unrelated individuals with microcephaly, intellectual disability, and epilepsy. In one individual, a homozygous variant in one of the double-stranded RNA-binding domains (dsRBDs) was identified. In the others, variants were situated in or around the deaminase domain. To evaluate the effects of these variants on ADAR2 enzymatic activity, we performed in vitro assays with recombinant proteins in HEK293T cells and ex vivo assays with fibroblasts derived from one of the individuals. We demonstrate that these ADAR2 variants lead to reduced editing activity on a known ADAR2 substrate. We also demonstrate that one variant leads to changes in splicing of ADARB1 transcript isoforms. These findings reinforce the importance of RNA editing in brain development and introduce ADARB1 as a genetic etiology in individuals with intellectual disability, microcephaly, and epilepsy.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Seizures
/
Genetic Variation
/
Adenosine Deaminase
/
RNA-Binding Proteins
/
Genetic Predisposition to Disease
/
Intellectual Disability
/
Microcephaly
Type of study:
Prognostic_studies
/
Risk_factors_studies
Limits:
Child
/
Child, preschool
/
Humans
/
Male
Language:
En
Journal:
Am J Hum Genet
Year:
2020
Document type:
Article
Publication country:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA