Genetic Epilepsy

Gene: SCAMP5

Green List (high evidence)

Four unrelated individuals reported with same de novo missense variant, p. Gly180Trp.

The onset age of seizures was ranged from 6 to 15 months. Patients had different types of seizures, including focal seizures, generalized tonic-clonic seizures and tonic seizure. One patient showed typical autism spectrum disorder (ASD) symptoms. Electroencephalogram (EEG) findings presented as focal or multifocal discharges, sometimes spreading to generalization. Brain magnetic resonance imaging (MRI) abnormalities were present in each patient. Severe intellectual disability and language and motor developmental disorders were found in our patients, with all patients having poor language development and were nonverbal at last follow-up. All but one of the patients could walk independently in childhood, but the ability to walk independently in one patient had deteriorated with age. All patients had abnormal neurological exam findings, mostly signs of extrapyramidal system involvement. Dysmorphic features were found in 2/4 patients, mainly in the face and trunk.

Created: 16 Jan 2021, 12:57 a.m. | Last Modified: 16 Jan 2021, 12:57 a.m.

Panel Version: 0.1003

2 unrelated individuals with ASD, ID and seizures, with the same heterozygous de novo variant in SCAMP5 (p.Gly302Trp). Western blot analysis of proteins overexpressed in the Drosophila fat body showed strongly reduced levels of the SCAMP p.Gly302Trp protein compared with the wild-type protein, indicating that the mutant either reduced expression or increased turnover of the protein. The expression of the fly homologue of the human SCAMP5 p.Gly180Trp mutation caused similar eye and neuronal phenotypes as the expression of SCAMP RNAi, suggesting a dominant-negative effect.
Sources: Literature

Created: 13 Dec 2019, 5:56 a.m.

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted

Phenotypes
Intellectual disability; seizures; autism

Publications

• 31439720
• 33390987

Mode of pathogenicity
Other