1. Longitudinal Characterization of the Clinical Course of Intermediate-Severe Salla Disease.
- Author
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Chapleau A, Mirchi A, Tran LT, Poulin C, and Bernard G
- Subjects
- Adolescent, Humans, Child, Child, Preschool, Mutation genetics, N-Acetylneuraminic Acid, Disease Progression, Sialic Acid Storage Disease genetics
- Abstract
Background: Biallelic pathogenic variants in SLC17A5 cause three forms of free sialic acid storage disease categorized based on severity from least to most severe: Salla disease, intermediate-severe Salla disease, and infantile free sialic acid storage disease. Intermediate-severe Salla disease is the most recently described form. Here, we report a longitudinal characterization of intermediate-severe Salla disease progression in two sisters carrying the following biallelic variants in SLC17A5: c.406A>G (p.Lys136Glu) and c.819+1G>A., Methods: A retrospective review of medical records was performed. A developmental questionnaire was completed to obtain further clinical information. For functional characterization of the predicted splice site variant, RNA was extracted from patient blood samples and sequenced., Results: Disease onset occurred within the first six months of life in both patients. Early childhood development was delayed with achievement of some milestones followed by a developmental plateau in late childhood. After this, both patients began a slow and progressive neurological regression in adolescence. Functional studies confirmed the pathogenicity of the c.819+1G>A variant, resulting in a frameshift and deletion of exon 6., Conclusions: We present a detailed study describing the clinical course of intermediate-severe Salla disease with over 15 to 20 years of evolution and demonstrate the pathogenicity of the c.819+1G>A splice site variant., Competing Interests: Declaration of competing interest The authors declare no relevant conflicts of interest. Dr. Bernard is/was a consultant for Passage Bio Inc (2020-2021) and Ionis (2019). She is/was a site investigator for the Alexander's disease trial of Ionis (2021-present), Metachromatic leukodystrophy of Shire/Takeda (2020-2021), Krabbe and GM1 gene therapy trials of Passage Bio (2021-present), GM1 natural history study of Passage Bio (2021-present), and adrenoleukodystrophy/hematopoietic stem cell transplantation natural history study of Bluebird Bio (2019) and a site subinvestigator for the MPS II gene therapy trial of Regenxbio (2021-present) and the MPS II clinical trial of Denali (2022-present). She has received unrestricted educational grants from Takeda (2021-2022)., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2023
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