Correction to: Characteristics of taste dysfunction in COVID‑19 subjects coming from two different countries

Journal of NeuroVirology - A correction to this paper has been published: https://doi.org/10.1007/s13365-021-00976-y     

A Novel Regulatory Defect in the Branched‐Chain α‐Keto Acid Dehydrogenase Complex Due to a Mutation in the PPM1K Gene Causes a Mild Variant Phenotype of Maple Syrup Urine Disease

This article describes a hitherto unreported involvement of the phosphatase PP2Cm, a recently described member of the branched‐chain α‐keto acid dehydrogenase (BCKDH) complex, in maple syrup urine disease (MSUD). The disease‐causing mutation was identified in a patient with a mild variant phenotype, involving a gene not previously associated with MSUD. SNP array‐based genotyping showed a copy‐neutral homozygous pattern for chromosome 4 compatible with uniparental isodisomy. Mutation analysis of the candidate gene, PPM1K, revealed a homozygous c.417_418delTA change predicted to result in a truncated, unstable protein. No PP2Cm mutant protein was detected in immunocytochemical or Western blot expression analyses. The transient expression of wild‐type PPM1K in PP2Cm‐deficient fibroblasts recovered 35% of normal BCKDH activity. As PP2Cm has been described essential for cell survival, apoptosis and metabolism, the impact of its deficiency on specific metabolic stress variables was evaluated in PP2Cm‐deficient fibroblasts. Increases were seen in ROS levels along with the activation of specific stress‐signaling MAP kinases. Similar to that described for the pyruvate dehydrogenase complex, a defect in the regulation of BCKDH caused the aberrant metabolism of its substrate, contributing to the patient's MSUD phenotype—and perhaps others.     

Reliability and accuracy assessment of morphometric measurements obtained with software for three-dimensional reconstruction of brain aneurysms relative to cerebral angiography measures

ObjectiveTo analyze the reliability and accuracy of morphological measurements of software employed to three-dimensionally reconstruct aneurysms and vessels (VMTKlab, version 1.6.1,) with computed tomography angiography (CTA) as the source of images. Agreement with measurements from three-dimensional digital subtraction angiography (3 D-DSA) was evaluated.MethodsWe evaluated 40 patients presenting with aneurysmal subarachnoid hemorrhage (aSAH). We analyzed four main variables of the aneurysm morphology: absolute height (size), neck (maximum neck width), perpendicular height, and maximum width. The CTA images were uploaded to the software and then segmented to reconstruct the aneurysm. This new method was compared to the current gold standard—3D reconstruction of pretreatment cerebral angiography. We used intraclass correlation coefficient (ICC) and Bland-Altman plot analyses to evaluate the agreement between these methods.ResultsThe ICCs obtained for absolute height, neck, perpendicular height, and maximum width were 0.85, 0.57, 0.85, and 0.89, respectively. This implied good agreement except for the neck of the aneurysm (moderate agreement). Bland-Altman plots are presented for the four indexes. The average of the differences was not significant in terms of absolute height, perpendicular height, and maximum width indicating good agreement. However, it was significant for the neck of the aneurysm.ConclusionsWe report good agreement between the values generated using VMTKlab and cerebral angiography for three of the four main variables. Discrepancies in neck diameter are not surprising and its underestimation with a traditional delineation from cerebral angiography has been reported before.