Disease relevance of GABRA1

• OBJECTIVE: The objective of this study was to investigate functional mutations or polymorphisms of the GABA-A receptor alpha1-subunit gene (GABRA1) in girls with idiopathic gonadotropin-dependent precocious puberty (GDPP) with and without electroencephalographic (EEG) abnormalities [1].
• Purpose: Previous studies in neonatal (postnatal day 10) and adult rats suggest that status epilepticus (SE) induces changes in the alpha1 subunit of the GABA(A) receptor (GABRA1) in dentate granule neurons (DGNs) that are age dependent and vary inversely with the likelihood of epilepsy development [2].
• Genetic analysis of the GABRA1 gene in patients with essential tremor [3].
• Mutation screen of GABRA1, GABRB2 and GABRG2 genes in Japanese patients with absence seizures [4].
• An Ala322Asp mutation in the GABRA1 gene was recently reported to be responsible for causing the autosomal dominant (AD) form of juvenile myoclonic epilepsy (JME) in a French-Canadian family [5].

Psychiatry related information on GABRA1

• The possible association of GABRA1 with the psychopathology of major psychoses was tested both alone and in interaction with DRD4 [6].
• DRD2, DRD4 and GABRA1 variants therefore do not appear to be associated with the outcome of lithium prophylaxis in mood disorders [7].
• CONCLUSIONS: These results indicate that the GABRA1 gene may play a role in the etiology of bipolar disorders [8].
• METHODS: We performed mutation screening of GABRA1 in 24 Japanese bipolar patients and evaluated associations in Japanese case-control subjects consisting of 125 patients with bipolar disorder, 147 patients with depressive disorders, and 191 healthy control subjects [8].
• RESULTS: In GABRA1, we found evidence of association with several of the drinking behavior phenotypes, including COGA alcohol dependence, history of blackouts, age at first drunkenness, and level of response to alcohol [9].

High impact information on GABRA1

• Our results confirm that mutation of GABRA1 predisposes towards a common idiopathic generalized epilepsy syndrome in humans [10].
• We report that an Ala322Asp mutation in GABRA1, encoding the alpha1 subunit of the gamma-aminobutyric acid receptor subtype A (GABA(A)), is found in affected individuals of a large French Canadian family with juvenile myoclonic epilepsy [10].
• Comparison of transcript levels in schizophrenia patients and unaffected siblings found lower patient expression of GABRA6 and coexpressed genes of GABRA1 [11].
• The GABRA1 and GABRP findings were replicated in the second stage in an independent German family-based sample (P=0.0015-0.043) [11].
• Interestingly, the GABRA1 coexpressed genes include synaptic and vesicle-associated genes previously found altered in schizophrenia prefrontal cortex [11].

Chemical compound and disease context of GABRA1

• In this study, we investigated the possibility that the gene for the gamma-aminobutyric acid type A (GABAA) receptor alpha-1 subunit (GABRA1) might be associated with depressive symptomatology in a sample of mood disorder subjects [12].

Biological context of GABRA1

• Genes encoding GABRA1 and GABRA6, on chromosome 5, did not provide evidence for association with alcoholism [13].
• A gene cluster consisting of the four gamma-aminobutyric acidA (GABAA) receptor subunit genes GABRA1, GABRA6, GABRAB2, and GABRG2 was assigned to a yeast artificial chromosome (YAC) contig of 5q33 [14].
• The genotype and allele frequencies of the GABRA1 polymorphisms were not statistically different between unrelated GDPP girls and controls or between GDPP girls with or without EEG abnormalities [1].
• Possible association between a haplotype of the GABA-A receptor alpha 1 subunit gene (GABRA1) and mood disorders [8].
• The GABRA1 gene encodes one of the subunits of GABA-A receptor and is located on human chromosome 5q34-q35, which is a region reportedly linked to mood disorders [8].

Anatomical context of GABRA1

• Conclusions: P20 SE results in persistent increases in GABRA1 levels selectively in dentate gyrus [2].
• GABRA1 mRNA changes were region specific and did not occur in CA1 or CA3 areas of hippocampus [2].

Associations of GABRA1 with chemical compounds

• DRD2, DRD4 and GABRA1 variants were not associated with response to lithium [7].
• GABRA1 alterations were present by 1 week after P20 SE and were similar whether pilocarpine or kainate was used to induced SE [2].

Regulatory relationships of GABRA1

• GABRA1 variants did not significantly influence the association of DRD4 with delusional symptoms [6].

Other interactions of GABRA1

• These results reveal the clustering of GABRA6, GABRA1, and the GABAA receptor gamma 2-subunit gene (GABRG2) on distal chromosome 5q [15].
• The order of the GABR subunit genes with respect to known anonymous gene loci is cen-D5S380 - D5S403 - D5S529 - GABRB2 - GABRA1/A6 - GABRG2-D 5S422-tel [14].

Analytical, diagnostic and therapeutic context of GABRA1

• Four hundred and sixty-one inpatients affected by major psychoses were assessed by the operational criteria checklist for psychotic illness (OPCRIT) and were also typed for the DRD4 and GABRA1 variants using PCR techniques [6].
• CONCLUSIONS: GABRA1 functional mutations or polymorphisms are not associated with the intrinsic mechanism of GDPP in girls with and without EEG abnormalities [1].
• GABRA1 mRNA and protein levels were determined 7 days or 3 months later in SE-exposed and control animals by using a combination of aRNA amplification, Western blotting, and immunohistochemistry techniques [2].

References