Autism Spectrum disorder (ASD) and intellectual disability (ID) are the most frequent develop-mental disorders with a prevalence between 3% and 5% of the population. In addition, both ASD and ID can be found in the same patient. Mutations in several genes involved in the epigenetic regulation of gene expression have been linked to different ID associated with ASD features including alterations of the ly-sine-acetyltransferase 6A (KAT6A) gene in KAT6A syndrome. KAT6A enzyme participates in a wide range of critical cellular functions such as chromatin remodeling, gene expression, protein synthesis, cell metabolism, and replication. In this manuscript, we examined the pathophysiolog-ical alterations in fibroblasts derived from three patients harboring KAT6A mutations. We ad-dressed survival in stress medium, histone acetylation, protein expression patterns and tran-scriptome analysis as well as cell bioenergetics. In addition, we evaluated the therapeutic effec-tiveness of epigenetic modulators and mitochondrial boosting agents such as pantothenate and L-carnitine in correcting the mutant phenotype. Pantothenate and L-carnitine treatment increased histone acetylation and corrected protein and transcriptomic expression patterns in mutant KAT6A cells. Furthermore, cell bioenergetics of mutant cells was significantly improved. Our results suggest that pantothenate and L-carnitine can significantly correct the mutant phe-notype in cellular models of KAT6A syndrome.

Mutations in the lipoyltransferase 1 (LIPT1) gene are rare inborn errors of metabolism leading to a fatal condition characterized by lipoylation defects of the 2-ketoacid dehydrogenase complexes causing early-onset seizures, psychomotor retardation, abnormal muscle tone, severe lactic aci-dosis and increased urine lactate, ketoglutarate, and 2-oxoacids levels. In this article, we characterized the disease pathophysiology using fibroblasts and induced neurons derived from a patient bearing a compound heterozygous mutation in LIPT1. Western blot analysis revealed reduced expression of LIPT1 and absent expression of lipoylated pyruvate dehydrogenase E2 (PDH E2) and alpha-ketoglutarate dehydrogenase E2 (α-KGDH E2) subunits. Accordingly, activities of PDH and α-KGDH were markedly reduced, associated with cell bioenergetics failure, iron accumulation and lipid peroxidation. In addition, using a pharmacological screening, we identified a cocktail of antioxidants and mitochondrial boosting agents consisting of pantothenate, nicotinamide, vitamin E, thiamine, biotin, and alpha-lipoic acid, which is capable of rescuing LIPT1 patho-physiology, increasing LIPT1 expression and lipoylation of mitochondrial proteins, improving cell bioenergetics, and eliminating iron overload and lipid peroxidation. Furthermore, our data suggest that the beneficial effect of the treatment is mainly mediated by SIRT3 activation. In conclusion, we have identified a promising therapeutic approach for correcting LIPT1 mutations.

Neurodegeneration with brain iron accumulation (NBIA) is a group of rare neurogenetic dis-orders frequently associated with iron accumulation in the basal nuclei of the brain. Among NBIA subtypes, β -propeller protein-associated neurodegeneration (BPAN) is associated with mutations in the autophagy gene WDR45. The aim of this study was to demonstrate autophagic defects and secondary pathological con-sequences in cellular models derived from two patient harboring WDR45 mutations. Both protein and mRNA expression levels of WDR45 were decreased in patient-derived fibro-blasts. In addition, the increase of LC3B upon treatments with autophagy inducers or inhibitors was lower in mutant cells compared to control cells, suggesting decreased autophagosome formation and impaired autophagic flux. Transmission electron microscopy (TEM) analysis showed mitochondrial vacuolization associated with accumulation of lipofuscin-like aggregates containing undegraded material. Autophagy dysregulation was also associated with iron ac-cumulation and lipid peroxidation. In addition, mutant fibroblasts showed altered mitochon-drial bioenergetics. Antioxidants such as pantothenate, vitamin E and α-lipoic prevented lipid peroxidation and iron accumulation. However, antioxidants were not able to correct the ex-pression levels of WDR45 neither the autophagy defect nor cell bioenergetics. Our study demonstrated that WDR45 mutations in BPAN cellular models impaired autophagy, iron metabolism and cell bioenergetics. Antioxidant partially improved cell physiopathology, however autophagy and cell bioenergetics remained affected.