Early onset or syndromic epilepsy
Gene: KCNH1
The rating of this gene has been updated to Green following NHS Genomic Medicine Service approval.Created: 1 Feb 2023, 9:39 a.m. | Last Modified: 1 Feb 2023, 9:39 a.m.
Panel Version: 3.29
Comment on list classification: Sufficient number of unrelated cases (>3) of epilepsy in patients with variants in the KCNH1 gene. Inclusion on this panel would be of particular benefit to individuals without typical gingival and/or nail anomalies and only mild developmental delays - who may not be tested under other panels (e.g. Limb disorders, ID) and thus may otherwise be missed in analysis.Created: 15 Apr 2021, 12:12 p.m. | Last Modified: 15 Apr 2021, 12:12 p.m.
Panel Version: 2.323
Well-established cause of Temple-Baraitser syndrome (MIM #611816) and Zimmermann-Laband syndrome (MIM #135500) characterised by ID with or without epilepsy, hypertrichosis and distinctive features such as gingival hyperplasia and nail hypoplasia/aplasia. Overall, sufficient number of cases with epilepsy to rate Green on this panel (PMIDs: 18203178; 20009591; 20683999; 21626675; 23994350; 25420144)
- PMID: 33811134 (2021) - 7 patients with de novo KCNH1 variants presenting mild/moderate to severe DD/ID, but without any distinctive features of TBS/ZLS such as gingival hyperplasia and nail anomalies. Four patients had epilepsy starting in infancy, with generalised tonic–clonic (4/4), myoclonic (2/4), focal motor (2/4) and tonic (1/4) seizures. One patient experienced status epilepticus. Epilepsy was pharmacoresponsive in all individuals. This study provides evidence of KCNH-related encephalopathy even without the presence of other extra-neurological symptoms that are typically associated with pathogenic variants in this gene.
Sources: LiteratureCreated: 15 Apr 2021, noon
Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Phenotypes
Temple-Baraitser syndrome, OMIM:611816; Zimmermann-Laband syndrome 1, OMIM:135500; Intellectual disability; Encephalopathy without features of TBS/ZLS
Publications
Tag Q2_21_rating was removed from gene: KCNH1.
Source Expert Review Green was added to KCNH1. Source NHS GMS was added to KCNH1. Rating Changed from Amber List (moderate evidence) to Green List (high evidence)
Gene: kcnh1 has been classified as Amber List (Moderate Evidence).
gene: KCNH1 was added gene: KCNH1 was added to Genetic epilepsy syndromes. Sources: Literature Q2_21_rating tags were added to gene: KCNH1. Mode of inheritance for gene: KCNH1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted Publications for gene: KCNH1 were set to 18203178; 20009591; 20683999; 21626675; 23994350; 25420144; 33811134 Phenotypes for gene: KCNH1 were set to Temple-Baraitser syndrome, OMIM:611816; Zimmermann-Laband syndrome 1, OMIM:135500; Intellectual disability; Encephalopathy without features of TBS/ZLS Review for gene: KCNH1 was set to GREEN