Early onset or syndromic epilepsy

Gene: SAMD12

I don't know

SAMD12 short tandem repeat variants have been associated with Epilepsy, familial adult myoclonic, 1 (OMIM:601068), but no phenotype was associated SAMD12 in Gen2Phen. The SAMD12 STR will be added to PanelApp after the variant details have been reviewed and confirmed by the NHS Genomic Medicine Service.

Created: 22 Jun 2023, noon | Last Modified: 22 Jun 2023, noon

Panel Version: 4.55

Green List (high evidence)

Repeat expansions of intronic TTTCA and TTTTA motifs within SAMD12 have been identified in over 50 Japanese and Chinese families. Most families with affected individuals were heterozygous however 4 patients from 3 families had homozygous repeat expansions, which was associated with a more severe phenotype. Western blot analysis showed decreased levels of the protein in patient brains. Note these were identified on long-read sequencing and may not be detectable by all assays.
Sources: Literature

Created: 23 Apr 2020, 3:44 a.m.

Mode of inheritance
BOTH monoallelic and biallelic (but BIALLELIC mutations cause a more SEVERE disease form), autosomal or pseudoautosomal

Phenotypes
Epilepsy, familial adult myoclonic, 1, MIM# 601068

Publications

• 30194086
• 29507423

Mode of pathogenicity
Other

Variants in this GENE are reported as part of current diagnostic practice