Expanding the phenotypic and molecular spectrum of NFS1-related disorders that cause functional deficiencies in mitochondrial and cytosolic iron-sulfur cluster containing enzymes.

Iron-sulfur cluster proteins are involved in critical functions for gene expression regulation and mitochondrial bioenergetics including the oxidative phosphorylation system. The c.215G>A p.(Arg72Gln) variant in NFS1 has been previously reported to cause infantile mitochondrial complex II and III deficiency. We describe three additional unrelated patients with the same missense variant. Two infants with the same homozygous variant presented with hypotonia, weakness and lactic acidosis, and one patient with compound heterozygous p.(Arg72Gln) and p.(Arg412His) variants presented as a young adult with gastrointestinal symptoms and fatigue. Skeletal muscle biopsy from patients 1 and 3 showed abnormal mitochondrial morphology, and functional analyses demonstrated decreased activity in respiratory chain complex II and variably in complexes I and III. We found decreased mitochondrial and cytosolic aconitase activities but only mildly affected lipoylation of pyruvate dehydrogenase and 2-oxoglutarate dehydrogenase enzymes. Our studies expand the phenotypic spectrum and provide further evidence for the pathogenicity and functional sequelae of NFS1-related disorders with disturbances in both mitochondrial and cytosolic iron-sulfur cluster containing enzymes.

Math anxiety, but not induced stress, is associated with objective numeracy.

Many daily activities require a basic understanding of math. Numeracy, which refers to individual differences in the ability to understand numerical concepts and work with probabilities, has been linked to health-related decision-making and medical and financial outcomes. Whether affective influences impact numeracy has not been experimentally assessed, although research has shown that emotions impact judgments and decision-making. Stress is one commonly experienced affective influence that could impact numeracy. We examined whether objective and subjective numeracy were influenced by stress induced from anticipating giving a speech in a laboratory setting. We also examined the association of self-reported math anxiety, or apprehension pertaining to mathematics, with objective and subjective numeracy. Two experiments were conducted; the second was a direct replication. Undergraduate students (Experiment 1, n = 99; Experiment 2, n = 139) were randomly assigned to one of two conditions: a stress induction or a neutral condition. Whereas neither objective nor subjective numeracy significantly differed across conditions, math anxiety was a consistent predictor of objective and subjective numeracy. Math anxiety and baseline perceived stress did not consistently moderate any effects. These findings have implications for health care, educational, and financial contexts in which people must make decisions that involve complex numbers. (PsycInfo Database Record (c) 2020 APA, all rights reserved).