Early onset or syndromic epilepsy
Gene: BTD
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: John Taylor and Helen Lord. 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
AR biotinidase deficiency also known as MCD - metabolic disorder characterised primarily by cutaneous and neurologic abnormalities due to inability to reutilise biotin - can treat with biotin. Wolf et al, 1985 - reviewed the clinical presentation of 31 children with late onset MCD due to biotin defic, symptoms usally appeared by 3 months with seizures as the most freq initial symptom. Other main features include hypotonia, hearing loss, optic atrophy, skin rash and alopecia. Pomponio et al,1995 - 10/25 patients with BTD - 7 bp del and 3 bp ins. In 1997 this group identified 21 mutations. The 2 most common were the del7/ins3 and R538C - 31/60 alleles. Remainmder were accounted for by 19 unique mutations. In 2000 this group identifed mutations in this gene in Turkish children diagnosed both clnically and by newborn screening. Is a biochemical test - not in the UK screening programme.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
Biotinidase deficiency, 253260
Publications
Comment when marking as ready: Associated with relevant phenotype in OMIM and as confirmed Gen2Phen gene. At least 4 variants reported 18 cases of Biotinidase deficiency 253260 that include seizures as part of the phenotype.Created: 12 Nov 2018, 5:14 p.m.
Comment on publications: PMID 24075304 mouse model, with seizures, PMIDs 4073853;3196050, seizures in patientsCreated: 12 Nov 2018, 5 p.m.
Gene-disease association firmly established, and seizures are part of the phenotype.Created: 8 Aug 2018, 1:38 a.m.
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Biotinidase deficiency, MIM#253260
Variants in this GENE are reported as part of current diagnostic practice
Source Wessex and West Midlands GLH was added to BTD.
Source NHS GMS was added to BTD.
Zornitza Stark: Gene-disease association firml
Gene: btd has been classified as Green List (High Evidence).
Gene: btd has been classified as Green List (High Evidence).
Publications for gene: BTD were set to 24075304; 4073853; 3196050
Publications for gene: BTD were set to
Mode of inheritance for gene: BTD was changed from to BIALLELIC, autosomal or pseudoautosomal
Phenotypes for gene: BTD were changed from to Biotinidase deficiency 253260
Expert Review Amber was added to BTD. Panel: Genetic Epilepsy Syndromes
Victorian Clinical Genetics Services was added to BTD. Panel: Genetic Epilepsy Syndromes
BTD was added to Genetic Epilepsy Syndromes panel. Sources: Expert Review Red,Expert
BTD was created by Sarah Leigh