Paroxysmal and non-paroxysmal dystonia in 3 patients with biallelic ECHS1 variants: Expanding the neurological spectrum and therapeutic approaches.

Illsinger, Sabine; Korenke, G Christoph; Boesch, Sylvia; Nocker, Michael; Karall, Daniela; Nuoffer, Jean M.; Laugwitz, Lucia; Mayr, Johannes A; Scholl-Bürgi, Sabine; Freisinger, Peter; Kowald, Tobias; Kölker, Stefan; Prokisch, Holger; Haack, Tobias B (2020). Paroxysmal and non-paroxysmal dystonia in 3 patients with biallelic ECHS1 variants: Expanding the neurological spectrum and therapeutic approaches. European journal of medical genetics, 63(11), p. 104046. Elsevier 10.1016/j.ejmg.2020.104046

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BACKGROUND

ECHS1 encodes the mitochondrial short chain enoyl CoA hydratase 1 (SCEH). Biallelic ECHS1 variants have been associated with Leigh-like presentations and milder phenotypes with paroxysmal exercise-induced dystonia.

PATIENTS/METHODS

We used exome sequencing to investigate molecular bases of paroxysmal and non-paroxysmal dystonia in three patients and performed functional studies in fibroblasts. Disease presentation and response upon dietary interventions were documented.

RESULTS

We identified compound heterozygous ECHS1 missense variants in all individuals; all of them harbouring an c.518C > T (p.Ala173Val) variant. SCEH activity was impaired in patients' fibroblasts, respiratory chain-, and pyruvate-dehydrogenase-complex activities were normal in one individual. Patient 1 presented from the age of 2.5 years on with paroxysmal opisthotonic posturing. Patient 2 had a first metabolic crisis at the age 20 months developing recurrent exercise-induced dystonic episodes. Disease history of patient 3 was unremarkable for neurological findings until he first presented at the age of 20 years with persistent dystonia. Ketogenic diet had beneficial effects in patient 1. Neither ketogenic nor low protein diets led to milder symptoms in patient 2. Patient 3 benefits from low protein diet with improvement of his torticollis.

CONCLUSIONS

In line with literature, our findings corroborate that the pathogenic ECHS1 variant c.518C > T (p.Ala173Val) is associated with milder phenotypes characterized by paroxysmal and non-paroxysmal dystonia. Because of the potentially treatable defect, especially in milder affected patients, it is important to consider SCEH deficiency not only in patients with Leigh-like syndrome but also in patients with paroxysmal dystonia and normal neurological findings between episodes.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > BioMedical Research (DBMR) > Unit Childrens Hospital > Forschungsgruppe Endokrinologie / Diabetologie / Metabolik (Pädiatrie)
04 Faculty of Medicine > Department of Haematology, Oncology, Infectious Diseases, Laboratory Medicine and Hospital Pharmacy (DOLS) > Institute of Clinical Chemistry
04 Faculty of Medicine > Department of Gynaecology, Paediatrics and Endocrinology (DFKE) > Clinic of Paediatric Medicine

UniBE Contributor:

Nuoffer, Jean-Marc

Subjects:

600 Technology > 610 Medicine & health

ISSN:

1878-0849

Publisher:

Elsevier

Language:

English

Submitter:

Karin Balmer

Date Deposited:

21 Dec 2020 09:03

Last Modified:

27 Dec 2020 02:50

Publisher DOI:

10.1016/j.ejmg.2020.104046

PubMed ID:

32858208

Uncontrolled Keywords:

Dystonia ECHS1 Exercise-induced Ketogenic diet Opisthotonus Paroxysmal

BORIS DOI:

10.7892/boris.148716

URI:

https://boris.unibe.ch/id/eprint/148716

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