Early onset or syndromic epilepsy

Gene: TANGO2

I don't know

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

Green List (high evidence)

AR recurrent metabolic encephalomyopathic crisis with rhabdomyolosis, cardiac arrhythmias and neurodegeneration. Lalani et al, 2016 - 12 aff individuals from 9 families with episodic rhabdomyolosis - 9/12 had seizures. Hom/compound het variants detected in all, recurrent hom missense variant detected in 4 unrelated Hispanic probands and a hom deletion was found in 4 probands from 2 families of European origin. Kremer et al, 2016 - 3 unrelated individuals with recurrent encephalomyopathic crisis, epilepsy was part of the overall disease course - hom or compound het variants detected in all.

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
Metabolic encephalomyopathic crises recurrent with rhabdomyolysis cardiac arrhythmias and neurodegeneration, 616878

Publications

• 26805782
• 30245509

Comment when marking as ready: Associated with relevant phenotype in OMIM and as confirmed Gen2Phen gene. At least three variants reported 7 unrelated cases in which seizures are a phenotypic feature.

Created: 11 Dec 2018, 10:58 a.m.

Comment on list classification: Based on reviewer's comments and sufficient evidence from the literature.

Created: 11 Dec 2018, 10:51 a.m.

Green List (high evidence)

Biallelic pathogenic variants in TANGO2 cause Metabolic encephalomyopathic crises, recurrent, with rhabdomyolysis, cardiac arrhythmias, and neurodegeneration, MIM 616878

PMIDs: 29369572 and 30245509 are both reviews on the disorder. Epilepsy is a feature in 70-80% of the patients (29 individuals reviewed in the second article).

According to PMID: 29369572 "Seizures are observed outside the periods of crises in more than 75% of individuals". PMID 30245509 notes that seizures occurred in a small minority of patients only during periods of crises secondary to hypoglycemia or associated with arrhythmia.

TANGO2 is included in gene panels for epilepsy offered by (few) diagnostic laboratories. The gene is already present in the ID and mitochondrial disorders panels as green.

As a result, this gene can also be considered for inclusion in this panel as green.
Sources: Literature

Created: 10 Dec 2018, 2:27 a.m.

Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal

Phenotypes
Metabolic encephalomyopathic crises, recurrent, with rhabdomyolysis, cardiac arrhythmias, and neurodegeneration, MIM 616878

Publications

• 29369572
• 30245509

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