Early onset or syndromic epilepsy
Gene: DBT
Gene is associated with Maple syrup urine disease, which can be associated with seizures if not properly controlled.Created: 6 Aug 2019, 8:31 p.m. | Last Modified: 6 Aug 2019, 8:31 p.m.
Panel Version: 1.188
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Maple syrup urine disease,type II 248600
Publications
Review and rating collated by Tracy Lester (Oxford Medical Genetics Laboratories Oxford University Hospitals NHS Foundation Trust, 2019_02_06) on behalf of Wessex and West Midlands GLH for GMS Neurology specialist test group, for Clinical Indication R59 'Early onset or syndromic epilepsy'. Review contributors: Alison Callaway and John Taylor. Suggested gene rating: Green.Created: 6 Aug 2019, 8:38 p.m. | Last Modified: 6 Aug 2019, 8:38 p.m.
Panel Version: 1.189
Comment on list classification: Updated rating from Amber to Green following publication of two 2019 papers (PMID:31112740 and PMID:31119508) who report MSUD patients with seizures and biallelic variants in DBT. Each paper reports individuals from a different ethnic group. Sufficient unrelated cases for a diagnostic-green rating.Created: 4 Jul 2019, 12:59 p.m. | Last Modified: 4 Jul 2019, 12:59 p.m.
Panel Version: 1.113
PMID:31112740. Yang et al 2019 identify a Chinese patient with MSUD (Patient 2) with compound het DBT variants: missense p.Leu69Arg and nonsense R291*. Patient 2 was recorded with Convulsions (Table 1). Leu69 is located in the LBD of the encoded BCKD protein, and therefore likely to affect the function of the protein. Segregation analysis was not performed. The 1000 Genome Project data was used to filter the data, and variants were validated by Sanger sequencing.Created: 4 Jul 2019, 12:54 p.m. | Last Modified: 4 Jul 2019, 12:54 p.m.
Panel Version: 1.112
PMID:31119508. Abiri et al. 2019 investigated the mutation spectrum of MSUD patients in 40 unrelated Iranian families. 5 patients (P36-P40) had homozygous or compound het variants in DBT. 4/5 of these patients had seizures reported. Four of the DBT variants were novel. None of the variants are present in controls including ExAC and the Iranome. Different variants reported in each of the 5 patients suggesting the patients are unrelated.Created: 4 Jul 2019, 12:39 p.m. | Last Modified: 4 Jul 2019, 12:39 p.m.
Panel Version: 1.110
Comment on list classification: Kept rating as Amber: DBT encodes the E2 subunit of the BCKD complex. The other complex subunits (BCKDHA and BCKDHB) are Green on this panel, and all 3 genes are associated with Maple syrup urine disease (MSUD, MIM:248600). Seizures are a recognised symptom of MSUD, and although there is generalized information about DBT causing intermediate forms of the disease with later-onset seizures, specific cases with DBT variants are required before promoting to Green.Created: 3 Dec 2018, 11:55 a.m.
Seizures are a feature of this metabolic condition.Created: 12 Aug 2018, 6:07 a.m.
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Maple syrup urine disease, type II, MIM#248600
Variants in this GENE are reported as part of current diagnostic practice
Source Wessex and West Midlands GLH was added to DBT.
Source NHS GMS was added to DBT.
Tag watchlist was removed from gene: DBT.
Phenotypes for gene: DBT were changed from Maple syrup urine disease, type II, 248600 to Maple syrup urine disease, type II, 248600; seizures; convulsions
Publications for gene: DBT were set to
Gene: dbt has been classified as Green List (High Evidence).
Zornitza Stark: Seizures are a feature of this
Gene: dbt has been classified as Amber List (Moderate Evidence).
Gene: dbt has been classified as Amber List (Moderate Evidence).
Tag watchlist tag was added to gene: DBT.
Phenotypes for gene: DBT were changed from to Maple syrup urine disease, type II, 248600
Mode of inheritance for gene: DBT was changed from to BIALLELIC, autosomal or pseudoautosomal
Expert Review Amber was added to DBT. Panel: Genetic Epilepsy Syndromes
DBT was added to Genetic Epilepsy Syndromes panel. Sources: Victorian Clinical Genetics Services
DBT was created by Sarah Leigh